A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
Contractile tissue that produces movement in animals.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
Muscular contractions characterized by increase in tension without change in length.
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
The nonstriated involuntary muscle tissue of blood vessels.
Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.
A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.
Use of electric potential or currents to elicit biological responses.
Contraction of the UTERINE MUSCLE.
Developmental events leading to the formation of adult muscular system, which includes differentiation of the various types of muscle cell precursors, migration of myoblasts, activation of myogenesis and development of muscle anchorage.
Contractile activity of the MYOCARDIUM.
That phase of a muscle twitch during which a muscle returns to a resting position.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
Skeletal muscle fibers characterized by their expression of the Type II MYOSIN HEAVY CHAIN isoforms which have high ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment. Several fast types have been identified.
Skeletal muscle fibers characterized by their expression of the Type I MYOSIN HEAVY CHAIN isoforms which have low ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
Non-striated, elongated, spindle-shaped cells found lining the digestive tract, uterus, and blood vessels. They are derived from specialized myoblasts (MYOBLASTS, SMOOTH MUSCLE).
Skeletal muscle structures that function as the MECHANORECEPTORS responsible for the stretch or myotactic reflex (REFLEX, STRETCH). They are composed of a bundle of encapsulated SKELETAL MUSCLE FIBERS, i.e., the intrafusal fibers (nuclear bag 1 fibers, nuclear bag 2 fibers, and nuclear chain fibers) innervated by SENSORY NEURONS.
The cartilaginous and membranous tube descending from the larynx and branching into the right and left main bronchi.
The resection or removal of the innervation of a muscle or muscle tissue.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
One of two types of muscle in the body, characterized by the array of bands observed under microscope. Striated muscles can be divided into two subtypes: the CARDIAC MUSCLE and the SKELETAL MUSCLE.
Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.
The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.
Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.
The neck muscles consist of the platysma, splenius cervicis, sternocleidomastoid(eus), longus colli, the anterior, medius, and posterior scalenes, digastric(us), stylohyoid(eus), mylohyoid(eus), geniohyoid(eus), sternohyoid(eus), omohyoid(eus), sternothyroid(eus), and thyrohyoid(eus).
The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .
A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.
The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.
A movement, caused by sequential muscle contraction, that pushes the contents of the intestines or other tubular organs in one direction.
Neurons which activate MUSCLE CELLS.
The properties, processes, and behavior of biological systems under the action of mechanical forces.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
The smaller subunits of MYOSINS that bind near the head groups of MYOSIN HEAVY CHAINS. The myosin light chains have a molecular weight of about 20 KDa and there are usually one essential and one regulatory pair of light chains associated with each heavy chain. Many myosin light chains that bind calcium are considered "calmodulin-like" proteins.
A protein found in the thin filaments of muscle fibers. It inhibits contraction of the muscle unless its position is modified by TROPONIN.
Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)
Elements of limited time intervals, contributing to particular results or situations.
These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.
Muscle contraction with negligible change in the force of contraction but shortening of the distance between the origin and insertion.
A vague complaint of debility, fatigue, or exhaustion attributable to weakness of various muscles. The weakness can be characterized as subacute or chronic, often progressive, and is a manifestation of many muscle and neuromuscular diseases. (From Wyngaarden et al., Cecil Textbook of Medicine, 19th ed, p2251)
Muscles forming the ABDOMINAL WALL including RECTUS ABDOMINIS, external and internal oblique muscles, transversus abdominis, and quadratus abdominis. (from Stedman, 25th ed)
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
The quadriceps femoris. A collective name of the four-headed skeletal muscle of the thigh, comprised of the rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.
One of the three polypeptide chains that make up the TROPONIN complex of skeletal muscle. It is a calcium-binding protein.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal (MUSCLE FIBERS, SKELETAL), cardiac (MYOCYTES, CARDIAC), and smooth (MYOCYTES, SMOOTH MUSCLE). They are derived from embryonic (precursor) muscle cells called MYOBLASTS.
Muscles of facial expression or mimetic muscles that include the numerous muscles supplied by the facial nerve that are attached to and move the skin of the face. (From Stedman, 25th ed)
The relationship between the dose of an administered drug and the response of the organism to the drug.
The motor activity of the GASTROINTESTINAL TRACT.
The rotational force about an axis that is equal to the product of a force times the distance from the axis where the force is applied.
A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.
Muscles arising in the zygomatic arch that close the jaw. Their nerve supply is masseteric from the mandibular division of the trigeminal nerve. (From Stedman, 25th ed)
A group of intracellular-signaling serine threonine kinases that bind to RHO GTP-BINDING PROTEINS. They were originally found to mediate the effects of rhoA GTP-BINDING PROTEIN on the formation of STRESS FIBERS and FOCAL ADHESIONS. Rho-associated kinases have specificity for a variety of substrates including MYOSIN-LIGHT-CHAIN PHOSPHATASE and LIM KINASES.
The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. (Stedman, 25th ed)
The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.
The synapse between a neuron and a muscle.
Drugs used to cause constriction of the blood vessels.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.
A protein complex of actin and MYOSINS occurring in muscle. It is the essential contractile substance of muscle.
An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.
A powerful flexor of the thigh at the hip joint (psoas major) and a weak flexor of the trunk and lumbar spinal column (psoas minor). Psoas is derived from the Greek "psoa", the plural meaning "muscles of the loin". It is a common site of infection manifesting as abscess (PSOAS ABSCESS). The psoas muscles and their fibers are also used frequently in experiments in muscle physiology.
One of the minor protein components of skeletal muscle. Its function is to serve as the calcium-binding component in the troponin-tropomyosin B-actin-myosin complex by conferring calcium sensitivity to the cross-linked actin and myosin filaments.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
A masticatory muscle whose action is closing the jaws.
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
Acquired, familial, and congenital disorders of SKELETAL MUSCLE and SMOOTH MUSCLE.
Respiratory muscles that arise from the lower border of one rib and insert into the upper border of the adjoining rib, and contract during inspiration or respiration. (From Stedman, 25th ed)
A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.
The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.
An enzyme that phosphorylates myosin light chains in the presence of ATP to yield myosin-light chain phosphate and ADP, and requires calcium and CALMODULIN. The 20-kDa light chain is phosphorylated more rapidly than any other acceptor, but light chains from other myosins and myosin itself can act as acceptors. The enzyme plays a central role in the regulation of smooth muscle contraction.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
The portion of the descending aorta proceeding from the arch of the aorta and extending to the DIAPHRAGM, eventually connecting to the ABDOMINAL AORTA.
The recording of muscular movements. The apparatus is called a myograph, the record or tracing, a myogram. (From Stedman, 25th ed)
A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Derangement in size and number of muscle fibers occurring with aging, reduction in blood supply, or following immobilization, prolonged weightlessness, malnutrition, and particularly in denervation.
Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
The rate dynamics in chemical or physical systems.
The larger subunits of MYOSINS. The heavy chains have a molecular weight of about 230 kDa and each heavy chain is usually associated with a dissimilar pair of MYOSIN LIGHT CHAINS. The heavy chains possess actin-binding and ATPase activity.
Drugs that bind to and activate cholinergic receptors.
Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.
A phosphoprotein phosphatase that is specific for MYOSIN LIGHT CHAINS. It is composed of three subunits, which include a catalytic subunit, a myosin binding subunit, and a third subunit of unknown function.
The main trunk of the systemic arteries.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
A network of tubules and sacs in the cytoplasm of SKELETAL MUSCLE FIBERS that assist with muscle contraction and relaxation by releasing and storing calcium ions.
A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Fibrous bands or cords of CONNECTIVE TISSUE at the ends of SKELETAL MUSCLE FIBERS that serve to attach the MUSCLES to bones and other structures.
Myosin type II isoforms found in smooth muscle.
A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.
A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.
Reflex contraction of a muscle in response to stretching, which stimulates muscle proprioceptors.
Elongated, spindle-shaped, quiescent myoblasts lying in close contact with adult skeletal muscle. They are thought to play a role in muscle repair and regeneration.
The flow of BLOOD through or around an organ or region of the body.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
The inferior part of the lower extremity between the KNEE and the ANKLE.
A stable prostaglandin endoperoxide analog which serves as a thromboxane mimetic. Its actions include mimicking the hydro-osmotic effect of VASOPRESSIN and activation of TYPE C PHOSPHOLIPASES. (From J Pharmacol Exp Ther 1983;224(1): 108-117; Biochem J 1984;222(1):103-110)
The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.
Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.
An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.
The vessels carrying blood away from the heart.
The muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.
An endogenous substance found mainly in skeletal muscle of vertebrates. It has been tried in the treatment of cardiac disorders and has been added to cardioplegic solutions. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1996)
The pectoralis major and pectoralis minor muscles that make up the upper and fore part of the chest in front of the AXILLA.
An order of the class Amphibia, which includes several families of frogs and toads. They are characterized by well developed hind limbs adapted for jumping, fused head and trunk and webbed toes. The term "toad" is ambiguous and is properly applied only to the family Bufonidae.
The hollow, muscular organ that maintains the circulation of the blood.
One of the three polypeptide chains that make up the TROPONIN complex. It inhibits F-actin-myosin interactions.
Arteries which arise from the abdominal aorta and distribute to most of the intestines.
The excretory duct of the testes that carries SPERMATOZOA. It rises from the SCROTUM and joins the SEMINAL VESICLES to form the ejaculatory duct.
The time span between the beginning of physical activity by an individual and the termination because of exhaustion.
A sustained and usually painful contraction of muscle fibers. This may occur as an isolated phenomenon or as a manifestation of an underlying disease process (e.g., UREMIA; HYPOTHYROIDISM; MOTOR NEURON DISEASE; etc.). (From Adams et al., Principles of Neurology, 6th ed, p1398)
The spread of response if stimulation is prolonged. (Campbell's Psychiatric Dictionary, 8th ed.)
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
The larger air passages of the lungs arising from the terminal bifurcation of the TRACHEA. They include the largest two primary bronchi which branch out into secondary bronchi, and tertiary bronchi which extend into BRONCHIOLES and PULMONARY ALVEOLI.
Parts of the myosin molecule resulting from cleavage by proteolytic enzymes (PAPAIN; TRYPSIN; or CHYMOTRYPSIN) at well-localized regions. Study of these isolated fragments helps to delineate the functional roles of different parts of myosin. Two of the most common subfragments are myosin S-1 and myosin S-2. S-1 contains the heads of the heavy chains plus the light chains and S-2 contains part of the double-stranded, alpha-helical, heavy chain tail (myosin rod).
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
Region of the body immediately surrounding and including the ELBOW JOINT.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
The electrical response evoked in a muscle or motor nerve by electrical or magnetic stimulation. Common methods of stimulation are by transcranial electrical and TRANSCRANIAL MAGNETIC STIMULATION. It is often used for monitoring during neurosurgery.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
Resistance and recovery from distortion of shape.
A methylpyrrole-carboxylate from RYANIA that disrupts the RYANODINE RECEPTOR CALCIUM RELEASE CHANNEL to modify CALCIUM release from SARCOPLASMIC RETICULUM resulting in alteration of MUSCLE CONTRACTION. It was previously used in INSECTICIDES. It is used experimentally in conjunction with THAPSIGARGIN and other inhibitors of CALCIUM ATPASE uptake of calcium into SARCOPLASMIC RETICULUM.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.
Cells specialized to transduce mechanical stimuli and relay that information centrally in the nervous system. Mechanoreceptor cells include the INNER EAR hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.
Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.
A masticatory muscle whose action is closing the jaws; its posterior portion retracts the mandible.
Proteins which bind calmodulin. They are found in many tissues and have a variety of functions including F-actin cross-linking properties, inhibition of cyclic nucleotide phosphodiesterase and calcium and magnesium ATPases.
An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.
The excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
A calcium channel blocker that is a class IV anti-arrhythmia agent.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
Voluntary activity without external compulsion.
A tetrameric calcium release channel in the SARCOPLASMIC RETICULUM membrane of SMOOTH MUSCLE CELLS, acting oppositely to SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. It is important in skeletal and cardiac excitation-contraction coupling and studied by using RYANODINE. Abnormalities are implicated in CARDIAC ARRHYTHMIAS and MUSCULAR DISEASES.
Organic compounds containing the -CO-NH2 radical. Amides are derived from acids by replacement of -OH by -NH2 or from ammonia by the replacement of H by an acyl group. (From Grant & Hackh's Chemical Dictionary, 5th ed)
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
Drugs that selectively bind to and activate alpha adrenergic receptors.
Measurement of the pressure or tension of liquids or gases with a manometer.
Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
The portion of the leg in humans and other animals found between the HIP and KNEE.
The smooth muscle coat of the uterus, which forms the main mass of the organ.
Benzopyrroles with the nitrogen at the number one carbon adjacent to the benzyl portion, in contrast to ISOINDOLES which have the nitrogen away from the six-membered ring.
Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The muscles of the PHARYNX are voluntary muscles arranged in two layers. The external circular layer consists of three constrictors (superior, middle, and inferior). The internal longitudinal layer consists of the palatopharyngeus, the salpingopharyngeus, and the stylopharyngeus. During swallowing, the outer layer constricts the pharyngeal wall and the inner layer elevates pharynx and LARYNX.
A region of the lower extremity immediately surrounding and including the KNEE JOINT.
An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.
A monosynaptic reflex elicited by stimulating a nerve, particularly the tibial nerve, with an electric shock.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A 21-amino acid peptide produced in a variety of tissues including endothelial and vascular smooth-muscle cells, neurons and astrocytes in the central nervous system, and endometrial cells. It acts as a modulator of vasomotor tone, cell proliferation, and hormone production. (N Eng J Med 1995;333(6):356-63)
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
The smallest divisions of the arteries located between the muscular arteries and the capillaries.
A non-steroidal anti-inflammatory agent (NSAID) that inhibits the enzyme cyclooxygenase necessary for the formation of prostaglandins and other autacoids. It also inhibits the motility of polymorphonuclear leukocytes.
An imidazole derivative which is a metabolite of the antineoplastic agents BIC and DIC. By itself, or as the ribonucleotide, it is used as a condensation agent in the preparation of nucleosides and nucleotides. Compounded with orotic acid, it is used to treat liver diseases.
The superior portion of the body of the stomach above the level of the cardiac notch.
Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the PERINEUM. It extends between the PUBIC BONE anteriorly and the COCCYX posteriorly.
Force exerted when gripping or grasping.
An eleven-amino acid neurotransmitter that appears in both the central and peripheral nervous systems. It is involved in transmission of PAIN, causes rapid contractions of the gastrointestinal smooth muscle, and modulates inflammatory and immune responses.
The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.
An serine-threonine protein kinase that requires the presence of physiological concentrations of CALCIUM and membrane PHOSPHOLIPIDS. The additional presence of DIACYLGLYCEROLS markedly increases its sensitivity to both calcium and phospholipids. The sensitivity of the enzyme can also be increased by PHORBOL ESTERS and it is believed that protein kinase C is the receptor protein of tumor-promoting phorbol esters.
A process fundamental to muscle physiology whereby an electrical stimulus or action potential triggers a myocyte to depolarize and contract. This mechanical muscle contraction response is regulated by entry of calcium ions into the cell.
Embryonic (precursor) cells of the myogenic lineage that develop from the MESODERM. They undergo proliferation, migrate to their various sites, and then differentiate into the appropriate form of myocytes (MYOCYTES, SKELETAL; MYOCYTES, CARDIAC; MYOCYTES, SMOOTH MUSCLE).
Continuous involuntary sustained muscle contraction which is often a manifestation of BASAL GANGLIA DISEASES. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from MUSCLE SPASTICITY. (From Adams et al., Principles of Neurology, 6th ed, p73)
The physiologic or functional barrier to GASTROESOPHAGEAL REFLUX at the esophagogastric junction. Sphincteric muscles remain tonically contracted during the resting state and form the high-pressure zone separating the lumen of the ESOPHAGUS from that of the STOMACH. (Haubrich et al, Bockus Gastroenterology, 5th ed., pp399, 415)
Narrowing of the caliber of the BRONCHI, physiologically or as a result of pharmacological intervention.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
One of the three polypeptide chains that make up the TROPONIN complex. It is a cardiac-specific protein that binds to TROPOMYOSIN. It is released from damaged or injured heart muscle cells (MYOCYTES, CARDIAC). Defects in the gene encoding troponin T result in FAMILIAL HYPERTROPHIC CARDIOMYOPATHY.
A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)
A subclass of muscarinic receptor that mediates cholinergic-induced contraction in a variety of SMOOTH MUSCLES.
A condition characterized by abnormal posturing of the limbs that is associated with injury to the brainstem. This may occur as a clinical manifestation or induced experimentally in animals. The extensor reflexes are exaggerated leading to rigid extension of the limbs accompanied by hyperreflexia and opisthotonus. This condition is usually caused by lesions which occur in the region of the brainstem that lies between the red nuclei and the vestibular nuclei. In contrast, decorticate rigidity is characterized by flexion of the elbows and wrists with extension of the legs and feet. The causative lesion for this condition is located above the red nuclei and usually consists of diffuse cerebral damage. (From Adams et al., Principles of Neurology, 6th ed, p358)
Agents that inhibit the actions of the parasympathetic nervous system. The major group of drugs used therapeutically for this purpose is the MUSCARINIC ANTAGONISTS.
Pentacyclic triterpene saponins, biosynthesized from protoaescigenin and barringtogenol, occurring in the seeds of AESCULUS. It inhibits edema formation and decreases vascular fragility.
The amount of force generated by MUSCLE CONTRACTION. Muscle strength can be measured during isometric, isotonic, or isokinetic contraction, either manually or using a device such as a MUSCLE STRENGTH DYNAMOMETER.
A device that measures MUSCLE STRENGTH during muscle contraction, such as gripping, pushing, and pulling. It is used to evaluate the health status of muscle in sports medicine or physical therapy.
Drugs used to cause dilation of the blood vessels.
The artery formed by the union of the right and left vertebral arteries; it runs from the lower to the upper border of the pons, where it bifurcates into the two posterior cerebral arteries.
One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.

Inhibitory innervation of cat sphincter of Oddi. (1/15397)

1 Electrical stimulation with trains of 0.1-0.2 ms pulses of the cat isolated sphincter of Oddi inhibited the spontaneous contractile activity and lowered base-line tension considerably. A contraction usually followed the period of stimulation. 2 These inhibitory effects were prevented by tetrodotoxin 0.1-0.5 mug/ml but were not reduced by hexamethonilm, morphine, or blockade of alpha- or beta-adrenoreceptors of cholinoceptors with phenoxy-benzamine propranolol or atropine, respectively. 3 Adenosine-5'-triphosphate (ATP) and adenosine-5'-diphosphate (ADP) inhibited the spontaneous sphincter activity and caused relaxation thus mimicking the effects of the C-terminal octapeptide of cholecystokinin (C8-CCK), isoprenaline and prostaglandin E1 and E2. 4 ATP alone (greater than 100 mug/ml) or ATP (greater than 10 mug/ml) plus dipyridamole (1 mug/ml), relaxed the sphincter to the same degrees as did the field stimulation. 5 In sphincter maximally contracted by acetylcholine, the effect of stimulation was more marked than that recorded in uncontracted preparations. 6 The present findings suggest that the sphincter of Oddi receives inhibitory nerves that are neither cholinergic nor adrenergic.  (+info)

Single blind, randomised controlled trial of pelvic floor exercises, electrical stimulation, vaginal cones, and no treatment in management of genuine stress incontinence in women. (2/15397)

OBJECTIVE: To compare the effect of pelvic floor exercises, electrical stimulation, vaginal cones, and no treatment for genuine stress incontinence. DESIGN: Stratified, single blind, randomised controlled trial. SETTING: Multicentre. PARTICIPANTS: 107 women with clinically and urodynamically proved genuine stress incontinence. Mean (range) age was 49.5 (24-70) years, and mean (range) duration of symptoms 10.8 (1-45) years. INTERVENTIONS: Pelvic floor exercise (n=25) comprised 8-12 contractions 3 times a day and exercise in groups with skilled physical therapists once a week. The electrical stimulation group (n=25) used vaginal intermittent stimulation with the MS 106 Twin at 50 Hz 30 minutes a day. The vaginal cones group (n=27) used cones for 20 minutes a day. The untreated control group (n=30) was offered the use of a continence guard. Muscle strength was measured by vaginal squeeze pressure once a month. MAIN OUTCOME MEASURES: Pad test with standardised bladder volume, and self report of severity. RESULTS: Improvement in muscle strength was significantly greater (P=0.03) after pelvic floor exercises (11.0 cm H2O (95% confidence interval 7.7 to 14.3) before v 19.2 cm H2O (15.3 to 23.1) after) than either electrical stimulation (14.8 cm H2O (10. 9 to 18.7) v 18.6 cm H2O (13.3 to 23.9)) or vaginal cones (11.8 cm H2O (8.5 to 15.1) v 15.4 cm H2O (11.1 to 19.7)). Reduction in leakage on pad test was greater in the exercise group (-30.2 g; -43. 3 to 16.9) than in the electrical stimulation group (-7.4 g; -20.9 to 6.1) and the vaginal cones group (-14.7 g; -27.6 to -1.8). On completion of the trial one participant in the control group, 14 in the pelvic floor exercise group, three in the electrical stimulation group, and two in the vaginal cones group no longer considered themselves as having a problem. CONCLUSION: Training of the pelvic floor muscles is superior to electrical stimulation and vaginal cones in the treatment of genuine stress incontinence.  (+info)

Cerebellar Purkinje cell simple spike discharge encodes movement velocity in primates during visuomotor arm tracking. (3/15397)

Pathophysiological, lesion, and electrophysiological studies suggest that the cerebellar cortex is important for controlling the direction and speed of movement. The relationship of cerebellar Purkinje cell discharge to the control of arm movement parameters, however, remains unclear. The goal of this study was to examine how movement direction and speed and their interaction-velocity-modulate Purkinje cell simple spike discharge in an arm movement task in which direction and speed were independently controlled. The simple spike discharge of 154 Purkinje cells was recorded in two monkeys during the performance of two visuomotor tasks that required the animals to track targets that moved in one of eight directions and at one of four speeds. Single-parameter regression analyses revealed that a large proportion of cells had discharge modulation related to movement direction and speed. Most cells with significant directional tuning, however, were modulated at one speed, and most cells with speed-related discharge were modulated along one direction; this suggested that the patterns of simple spike discharge were not adequately described by single-parameter models. Therefore, a regression surface was fitted to the data, which showed that the discharge could be tuned to specific direction-speed combinations (preferred velocities). The overall variability in simple spike discharge was well described by the surface model, and the velocities corresponding to maximal and minimal discharge rates were distributed uniformly throughout the workspace. Simple spike discharge therefore appears to integrate information about both the direction and speed of arm movements, thereby encoding movement velocity.  (+info)

Spinal cord-evoked potentials and muscle responses evoked by transcranial magnetic stimulation in 10 awake human subjects. (4/15397)

Transcranial magnetic stimulation (TCMS) causes leg muscle contractions, but the neural structures in the brain that are activated by TCMS and their relationship to these leg muscle responses are not clearly understood. To elucidate this, we concomitantly recorded leg muscle responses and thoracic spinal cord-evoked potentials (SCEPs) after TCMS for the first time in 10 awake, neurologically intact human subjects. In this report we provide evidence of direct and indirect activation of corticospinal neurons after TCMS. In three subjects, SCEP threshold (T) stimulus intensities recruited both the D wave (direct activation of corticospinal neurons) and the first I wave (I1, indirect activation of corticospinal neurons). In one subject, the D, I1, and I2 waves were recruited simultaneously, and in another subject, the I1 and I2 waves were recruited simultaneously. In the remaining five subjects, only the I1 wave was recruited first. More waves were recruited as the stimulus intensity increased. The presence of D and I waves in all subjects at low stimulus intensities verified that TCMS directly and indirectly activated corticospinal neurons supplying the lower extremities. Leg muscle responses were usually contingent on the SCEP containing at least four waves (D, I1, I2, and I3).  (+info)

99mTc-labeled vasoactive intestinal peptide receptor agonist: functional studies. (5/15397)

Vasoactive intestinal peptide (VIP) is a naturally occurring 28-amino acid peptide with a wide range of biological activities. Recent reports suggest that VIP receptors are expressed on a variety of malignant tumor cells and that the receptor density is higher than for somatostatin. Our aims were to label VIP with 99mTc--a generator-produced, inexpensive radionuclide that possesses ideal characteristics for scintigraphic imaging--and to evaluate 99mTc-VIP for bioactivity and its ability to detect experimental tumors. METHODS: VIP28 was modified at the carboxy terminus by the addition of four amino acids that provided an N4 configuration for a strong chelation of 99mTc. To eliminate steric hindrance, 4-aminobutyric acid (Aba) was used as a spacer. VIP28 was labeled with 1251, which served as a control. Biological activity of the modified VIP28 agonist (TP3654) was examined in vitro using a cell-binding assay and an opossum internal anal sphincter (IAS) smooth muscle relaxivity assay. Tissue distribution studies were performed at 4 and 24 h after injection, and receptor-blocking assays were also performed in nude mice bearing human colorectal cancer LS174T. Blood clearance was examined in normal Sprague-Dawley rats. RESULTS: The yield of 99mTc-TP3654 was quantitative, and the yields of 125I-VIP and 1251-TP3654 were >90%. All in vitro data strongly suggested that the biological activity of 99mTc-TP3654 agonist was equivalent to that of VIP28. As the time after injection increased, radioactivity in all tissues decreased, except in the receptor-enriched tumor (P = 0.84) and in the lungs (P = 0.78). The tumor uptake (0.23 percentage injected dose per gram of tissue [%ID/g]) was several-fold higher than 125I-VIP (0.06 %ID/g) at 24 h after injection in the similar system. In mice treated with unlabeled VIP or TP3654, the uptake of 99mTc-TP3654 decreased in all VIP receptor-rich tissues except the kidneys. The blood clearance was biphasic; the alpha half-time was 5 min and the beta half-time was approximately 120 min. CONCLUSION: VIP28 was modified and successfully labeled with 99mTc. The results of all in vitro examinations indicated that the biological activity of TP3654 was equivalent to that of native VIP28 and tumor binding was receptor specific.  (+info)

Uterine peristalsis during the follicular phase of the menstrual cycle: effects of oestrogen, antioestrogen and oxytocin. (6/15397)

Uterine peristalsis, directing sustained and rapid sperm transport from the external cervical os or the cervical crypts to the isthmic part of the tube ipsilateral to the dominant follicle, changes in direction and frequency during the menstrual cycle, with lowest activity during menstruation and highest activity at mid cycle. It was therefore suggested that uterine peristalsis is under the control of the dominant follicle with the additional involvement of oxytocin. To test this hypothesis, vaginal sonography of uterine peristalsis was performed in the early, mid and late proliferative phases, respectively, of cycles of women treated with oestradiol valerate and with human menopausal gonadotrophin following pituitary downregulation, with clomiphene citrate and with intravenous oxytocin, respectively. Administration of oestradiol valerate resulted in oestradiol serum concentrations comparable with the normal cycle with a simulation of the normal frequency of peristaltic contractions. Elevated oestradiol concentrations and bolus injections of oxytocin resulted in a significant increase in the frequency of peristaltic contractions in the early and mid follicular phases, respectively. Chlomiphene tended, though insignificantly so, to suppress the frequency of peristaltic waves in the presence of elevated oestradiol concentrations. In the late follicular phase of the cycle extremely elevated oestradiol concentrations as well as the injection of oxytocin resulted only in an insignificant further increase of peristaltic frequency. In the normal cycles, as well as during extremely elevated oestradiol concentrations and following oxytocin administration, the peristaltic contractions were always confined to the subendometrial layer of the muscular wall. The results and the review of literature indicate that uterine peristalsis during the follicular phase of the menstrual cycle is controlled by oestradiol released from the dominant follicle with the probable involvement of oxytocin, which is presumably stimulated together with its receptor within the endometrial-subendometrial unit and therefore acting in an autocrine/paracrine fashion. Since unphysiological stimulation with oestradiol and oxytocin did not significantly increase the frequency of uterine peristalsis in the late follicular phase of the cycle it is assumed that normal preovulatory frequency of uterine peristalsis is at a level which cannot be significantly surpassed due to phenomena of refractoriness of the system.  (+info)

Adrenoreceptors of the guinea-pig urinary bladder. (7/15397)

1 Adrenaline, noradrenaline and isoprenaline (5 mug/ml) did not affect the resting tone of the isolated urinary bladder of the guinea-pig. 2 The catecholamines (1-2 mug/ml) inhibited neuronally evoked contractions at various stimulation frequencies; the inhibition was maximum at 2 Hz and minimum at 50 Hz. Isoprenaline produced maximum inhibition. 3 Propranolol (0.5 mug/ml) completely blocked the catecholamine-induced inhibition at all the frequencies employed. The concentration-response curves of isoprenaline at 2, 10 and 50 Hz were characteristically shifted by propranolol (50 ng/ml). Phenoxybenzamine (0.2 mug/ml) was totally ineffective. 4 In some experiments adrenaline significantly raised the tone of the bladder exposed to propranolol; this effect could be blocked by phenoxybenzamine. 5 Acetylcholine-induced bladder contractions were inhibited by adrenaline (2 mug/ml); the inhibition was completely blocked by propranolol (0.5 mug/ml). 6 The results indicate the presence of an inhibitory beta-adrenoceptor and suggest the possibility of an excitatory alpha-adrenoceptor in guinea-pig urinary bladder.  (+info)

The cat lung strip as an in vitro preparation of peripheral airways: a comparison of beta-adrenoceptor agonists, autacoids and anaphylactic challenge on the lung strip and trachea. (8/15397)

1 A new in vitro preparation, the isolated lung strip of the cat, is described for investigating the direct effect of drugs on the smooth muscle of the peripheral airways of the lung. The preparation comprises a thin strip of lung parenchyma which can be mounted in a conventional organ bath for isometric tension recording. Its pharmacological responses have been characterized and compared with the isolated tracheal preparation of the cat. 2 The lung strip exhibited an intrinsic tone which was relaxed by catecholamines, aminophylline and flufenamate. It was contracted strongly by histamine, prostaglandin F2alpha, acetylcholine, compound 48/80, potassium depolarizing solution and alternating current field stimulation. In contrast, the cat trachea was unresponsive to histamine and prostaglandin F2alpha and did not exhibit an intrinsic tone. 3 (-)-Isoprenaline and (-)-adrenaline were much more potent in relaxing the lung strip than the trachea. The potency order of relaxation responses to isoprenaline, adrenaline and (+/-)-noradrenaline in the lung strip was isoprenaline greater than adrenaline greater than noradrenaline but in the trachea was isoprenaline greater than noradrenaline greater than or equal to adrenaline. 4 beta2-Adrenoceptor selective agonists salbutamol and terbutaline were more potent in the lung strip than the trachea, suggesting beta2-adrenoceptors predominated in the lung strip. Propranolol was equipotent in inhibiting isoprenaline relexations of the lung strip and trachea, whereas practolol was much less effective in inhibiting lung strip than trachea, further supporting a predominance of beta2-adrenoceptors in lung strip and beta1-adrenoceptors in trachea. 5 Strong Schultz-Dale type contractions were elicited in both lung strips and trachea by Ascaris lumbricoides antigen in actively sensitized cats. The initial phase of the contractile response of the lung strip following challenge was shown to be due to histamine release and was absent in the trachea. The delayed phase of the contraction which took several minutes to develop in both the mepyramine-treated lung strip and trachea was not due to prostaglandins E1, F2alpha or bradykinin, the probable mediator being slow reacting substance of anaphylaxis (SRS-A). 6 It is concluded that the isolated lung strip of the cat is useful as an in vitro model for investigating the effect of drugs on the smooth muscle of the peripheral airways of the lungs.  (+info)

TY - JOUR. T1 - Brain functional connectivity is different during voluntary concentric and eccentric muscle contraction. AU - Yao, Wan X.. AU - Jiang, Zhiguo. AU - Li, Jinqi. AU - Jiang, Changhao. AU - Franlin, Crystal G.. AU - Lancaster, Jack L. AU - Huang, Yufei. AU - Yue, Guang H.. PY - 2016/11/15. Y1 - 2016/11/15. N2 - Previous studies report greater activation in the cortical motor network in controlling eccentric contraction (EC) than concentric contraction (CC) of human skeletal muscles despite lower activation level of the muscle associated with EC. It is unknown, however, whether the strength of functional coupling between the primary motor cortex (M1) and other involved areas in the brain differs as voluntary movements are controlled by a network of regions in the primary, secondary and association cortices. Examining fMRI-based functional connectivity (FC) offers an opportunity to measure strength of such coupling. To address the question, we examined functional MRI (fMRI) data ...
During an eccentric contraction, the muscle elongates while under tension due to an opposing force being greater than the force generated by the muscle.[1] Rather than working to pull a joint in the direction of the muscle contraction, the muscle acts to decelerate the joint at the end of a movement or otherwise control the repositioning of a load. This can occur involuntarily (when attempting to move a weight too heavy for the muscle to lift) or voluntarily (when the muscle is smoothing out a movement). Over the short-term, strength training involving both eccentric and concentric contractions appear to increase muscular strength more than training with concentric contractions alone.[2] During an eccentric contraction of the biceps muscle, the elbow starts the movement while bent and then straightens as the hand moves away from the shoulder. During an eccentric contraction of the triceps muscle, the elbow starts the movement straight and then bends as the hand moves towards the shoulder. ...
The foundations for this topic can be found in the previous 4 articles in the series. Building off the understanding of viscoelastic tissues that are sensitive to the rate at which force is applied, we will examine training strategies designed to maximize muscle stimulation while avoiding injury. There are 3 types of muscle contraction:. Concentric - the muscle is shortening while contracting (the positive rep). Isometric - the muscle does not change length while contracting. Eccentric - the muscle is lengthening while contracting (the negative rep). It is widely misstated, and then repeated by others, that eccentric contractions produce more force than isometric contractions which produce more force than concentric contractions. This is not true. The force generated by muscle contraction is determined by the equation for torque reviewed in the last article, independent of the shortening or lengthening during contraction (minus a subtle detail - hysteresis - which is beyond the scope of our ...
Definition of concentric contraction in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is concentric contraction? Meaning of concentric contraction as a finance term. What does concentric contraction mean in finance?
Static muscular contraction in anesthetized animals has been firmly established to reflexly increase arterial pressure. Although group III and IV muscle afferents are known to be responsible for this reflex pressor response, there is no evidence that the stimulation of muscle mechanoreceptors, many of which are supplied by group III fibers, plays a role in causing this contraction-induced reflex effect. To provide this evidence, we recorded renal sympathetic nerve activity in chloralose-anesthetized cats while contracting the triceps surae muscles. We found that static contraction tripled renal nerve activity within three seconds of its onset, an increase that was abolished by cutting the L6 and S2 dorsal roots. On average, the contraction-induced increase in renal nerve activity was observed 0.8 +/- 0.1 seconds after the onset of this maneuver. In addition, intermittent tetanic contractions synchronized renal nerve discharge so that a burst of activity was evoked by each contraction. A ...
Definition of eccentric contraction in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is eccentric contraction? Meaning of eccentric contraction as a finance term. What does eccentric contraction mean in finance?
Eccentric exercise or resistance training is currently being used as a form of rehabilitation for sport injuries, but also as an alternative form of exercise for the elderly, those affected by neurological disorders, COPD, cardiopulmonary disorders, and cancer.[6] Muscle loss is a big problem faced by the people afflicted with the above disorders and many cannot participate in rigorous exercise protocols. Eccentric muscle contractions produce high forces with low-energy cost. According to Hortobágyi due to these properties eccentric exercise has the greatest potential for muscle strengthening.[7] To strengthen muscle the external force must exceed the muscle while it lengthens.[8] The definition of eccentric contraction is almost the exact definition of muscle strengthening. Perceived muscle damage: There is a stipulation regarding eccentric contractions in that they actually cause muscle damage and injury. Eccentric contraction may result in delayed onset muscle soreness however; the ...
The main new findings from this study of afferent arterioles from normal C57BL/6 mice were that increasing the PP from 40 to 80 mm Hg caused a myogenic contraction accompanied by an increase in ROS signal whether detected by dihydroethidium or tempo-9AC. The fluorescent ROS signal was predominately O2 · −, because it was reduced by incubation with PEG-SOD or Tempol but not with PEG-CAT and was upstream from Ca2+ because it persisted in Ca2+-free medium. Incubation of vessels with Tempol, PEG-SOD, apocynin, or DPI reduced basal and myogenic tone, whereas PEG-CAT was not effective, indicating that the responses were enhanced by O2 · − generated from NADPH oxidase. The moderation of myogenic contractions by Tempol was prevented by preincubation with PEG-SOD but was preserved by preincubation with PEG-CAT. H2O2 caused contractions at concentrations ,50 μmol/L but inhibited myogenic responses at 25 μmol/L. l- NAME increased basal tone but did not affect pressure-induced ROS generation. ...
Looking for Isotonic Muscle Contraction? Find out information about Isotonic Muscle Contraction. contraction of a muscle at unchanging tension, expressed in a decrease in its length and an increase in its transverse section. Purely isotonic muscle... Explanation of Isotonic Muscle Contraction
It is intriguing how the mechanics of molecular motors is regulated to perform the mechanical work in living systems. In sharp contrast to the conventional wisdom, recent experiments indicated that motor force maintains ∼6 pN upon a wide range of filament loads during skeletal muscle contraction at the steady state. Here we find that this rather precise regulation which takes place in an essentially chaotic system, can be due to that a working motor is arrested in a transitional state when the motor force is ∼6 pN. Our analysis suggests that the motor force can be self-regulated through chemomechanical coupling, and motor force homeostasis is a built-in feature at the level of a single motor, which provides insights to understanding the coordinated function of multiple molecular motors existing in various physiological processes. With a coupled stochastic-elastic numerical framework, the kinetic model for a Actin-myosin-ATP cycle constructed in this work might pave the way to decently ...
The muscles can perform the same function in a specific segment (muscles of fast and slow contraction), and at the same time be antagonistic in relation to muscular action (flexors or extensors). The present research aimed to study the morphology, frequency and metabolism of fiber types and the contractile characteristics of extensor and flexors muscles of rabbit. We studied muscles anterior tibialis (AT), flexor digitorum supeficialis (FDS), extensor digitorum longus (EDL) and posterior tibialis (PT). The muscles were submitted to the techniques HE, NADH-TR and myofibrillar ATPase. In EDL and PT extensor muscles, the frequencies of red (SO + FOG) and white fibers (FG) were 68.77% and 31.23% versus 58.87% and 41.13%, respectively. In the AT and FDS flexor muscles, these frequencies were 75.14% and 24.86% versus 73.89% and 26.11%, respectively. In extensor muscles, the percentage of slow contraction fibers was 8.05% in EDL and 9.74% in PT, and in fast contraction, 91.95% in EDL and 90.26% in PT. ...
When a muscle contraction is required, it receives a message from the brain for voluntary contractions and from the spinal cord for reflex contractions. This message, called a nerve impulse or action potential, is carried along motoneurons to the muscle. It would not be practical for all the fibers in a given muscle to contract every time the motoneuron discharged an action potential. Therefore, before the motoneuron reaches the target muscle, it divides into many separate branches that independently activate groups of muscle fibers. These groupings are referred to as motor units. The number of fibers per motor unit depends on the specific muscle. A small muscle used for intricate movements will have less than 100 fibers per motor unit and less than 100 motor units in total. A large muscle used for weight-bearing and propulsion will have several thousand fibers per motor unit and several hundred motor units ...
Weight training is all about throwing the weights about right? Even the best bodybuilder of all time in my opinion, Arnie, named his video Pumping Iron which says a lot. Yet I find myself tearing my hair out when I watch most people in the gym lift weights, to be blunt their form is pretty poor. To be more specific, I am referring to their repetition tempo during each phase of the muscle contraction. Today I wanted to educate you a little on muscle contractions and the importance of utilising them.ConcentricConcentric muscle contractions occur when the muscle shortens, so a doing a bicep curl is a perfect example. Many people will perform this part of the repetition with very little control of the weight and instead employ a great deal of momentum to shift the resistance from A to B. This is a great way to go if building a super-sized ego is the main goal, but if building quality lean muscle tissue is something you are interested in I suggest you listen.During a concentric muscle contraction by
Before I start talking about using different contraction types in training and the benefits they will have, first I must explain to anyone who doesnt know about the 3 different types of contraction. Keeping it nice and basic, there are 3 different ways that your muscle can contract in order to move a part of your body. Concentric - a concentric contraction is where the muscle shortens in length causing your bodypart to move. For example when you concentrically contract your bicep, it shortens and your arm bends (flexes). Most people who will train will be primarily focused on this type of contraction as it is the one that moves the weight against the resistance. For example it is the concentric contraction that pushes the bar off your chest to lockout on a bench press. Eccentric - an eccentric contraction is the lengthening of the muscle. This occurs when you lower the weight under control. Its the opposite movement to the concentric contraction but it isnt the antagonistic muscle that
During a stretch- shortening cycle (SSC), muscle force attained during concentric contractions (shortening phase) is potentiated by the preceding eccentric contractions (lengthening phase). The purpose of this study was to examine the influence of joint angular velocity on force potentiation induced by SSC (SSC effect). Twelve healthy men (age, 24.2 ± 3.2 years; height, 1.73 ± 0.05 m; body mass, 68.1 ± 11.0 kg) participated in this study. Ankle joint angle was passively moved by a dynamometer, with range of motion from dorsiflexion (DF) 15° to plantarflexion (PF) 15°. Muscle contractions were evoked by tetanic electrical stimulation. Joint angular velocity of concentric contraction was set at 30°/s and 150°/s. Magnitude of SSC effect was calculated as the ratio of joint torque obtained by concentric contraction with preliminary eccentric contraction trial relative to that obtained by concentric contraction without preliminary eccentric contraction trial. As a result, magnitude of SSC effect
Below are two different but similar descriptions of muscle contraction that explain the processes involved in notification, contraction, and relaxation.. The following steps are involved in muscle contraction:. (1) The sequence of events leading to contraction is initiated somewhere in the central nervous system, either as voluntary activity from the brain or as reflex activity from the spinal cord.. (2) A motor neuron in the ventral horn of the spinal cord is activated, and an action potential passes outward in a ventral root of the spinal cord.. (3) The axon branches to supply a number of muscle fibers called a motor unit, and the action potential is conveyed to a motor end plate on each muscle fiber.. (4) At the motor end plate, the action potential causes the release of packets or quanta of acetylcholine into the synaptic clefts on the surface of the muscle fiber.. (5) Acetylcholine causes the electrical resting potential under the motor end plate to change, and this then initiates an action ...
Ever wonder how a muscle contracts to create movement? Weve come up with a simple guide to help you understand muscle contraction.
1. The effect of pH on excitation-contraction coupling in skeletal muscle of the toad was examined using a skinned fibre preparation which gives ready access to the intracellular environment while still allowing stimulation of Ca2+ release by the normal voltage-sensor mechanism. 2. In each fibre, depolarization-induced responses (produced by changing the ions in the bathing solution) were examined first at pH 7.1, and then at another pH between 6.1 and 8.0. At all pH levels examined, the first depolarization elicited a large response which was slightly greater (pH 7.6 and 8.0) or smaller (pH 6.6 and 6.1) than that at pH 7.1. The size of the first depolarization-induced response varied with pH in almost exactly the same manner as did the maximum Ca(2+)-activated response. The duration of the depolarization-induced response at all other pH levels was longer than at pH 7.1. 3. Repeated depolarizations (30 s or more apart) produced similar responses at pH 7.1, but at all other pH levels examined the ...
I do not know what natural contractions feel like however contractions brought on by pitocin are the precise absolute plain satan. At 38 weeks I woke to them happening every 10 minutes - tho they eased after I moved & they had been brief & not painful, so I didnt fear an excessive amount of.. Apply labor contractions are in any other case known as Braxton Hicks contractions and are widespread from week 32 until birth. Nonetheless, in the event youre writing a tutorial paper or the rest thats formal, you could want to keep away from contractions. The time between contractions includes the length or length of the contraction and the minutes in between the contractions (called the interval).. Should you go to the hospital only to search out out that youre having false labor, dont feel unhealthy about it. It is sometimes laborious to know the difference between actual and false labor. One of the reasons it is troublesome to answer the question what do contractions feel like is because the ...
I have to do a literature review on a topic involving neurophysiology. So I chose to pick one about the force-velocity relationship of muscle contractions. The relationship shows that as muscle velocity increases, muscle force decreases. I was wondering if anybody has any research articles that show the opposite: That as velocity increases muscle force increases as well. I have searched to no avail. I appreciate any help.
Types of Contraction. All types of strength are a result of individual muscle fibres contracting, a muscle fibre contracts fully or not at all, the number of muscle fibres that contract simultaneously define the amount of force a muscle can produce and whether that muscle can overcome, maintain, or slowly lower the load its working against.. If the force generated by the muscle fibres is greater than the load, then the entire muscle length will shorten and the load will move, this is called a Concentric Contraction.. When the load is greater than the force produced by the muscle fibres the muscle will lengthen, this is called an Eccentric Contraction, even though the muscle as a whole is lengthening, individual fibres are still contracting trying to resist the load.. Concentric/Eccentric contractions are collectively known as Dynamic contractions. When the force exerted by the fibres is equal to the load no movement takes place, this is called an Isometric Contraction. This of special interest ...
Trusculpt flex involves direct stimulation of muscles through the electrodes located in the handpiece, resulting in full muscle contractions similar to voluntary contractions during physical exercise. The contractions induced by truSculpt flex are more intense than physical exercise and such rapid contractions result in increased muscle mass, strength, and tone. One of the limitations of electrical muscle stimulation in increasing muscle strength is that the same muscles that are superficially located are recruited during repetitive use3. This can lead to muscle fatigue and damage. truSculpt flex overcomes this limitation by using multi-directional stimulation with 3 treatment modes, involving different current intensities. Increasing current intensity through the course of a training session allows for the recruitment of deeper muscle groups during training and thus avoids muscle damage4. Altering the direction of the current can also avoid stimulation of the same muscles and facilitate ...
Several studies reported that exercising one limb produces gains in motor output in the same muscle of the un-exercised, contralateral limb. This phenomenon is called cross education. There are also data to suggest that muscle and brain activation are different when muscles shorten and lengthen and that the amount of cross education may be also different according to the type of muscle contraction. This thesis is an initial effort in the form of a cross sectional study to shed light on the mechanism of cross education. This project examines the hypothesis that spinal excitability varies in the resting limb according to the type and intensity of muscle contraction in the contralateral limb. The purpose of this study was to compare spinal excitability in the right wrist flexors during and after concentric and eccentric contraction of the left wrist flexors at an intensity of 100% and 60% of the maximum. Ten healthy right-handed subjects (5 females, 5 males, mean age 21 [plus/minus] 3 years) ...
Researchers in the Department of Human Health and Nutritional Sciences have gained new insights into the fundamental properties that govern muscle activity and influence our day-to-day movement.. Prof. Geoffrey Power and his research group have discovered a unique interplay between our nervous system and a phenomenon that occurs during muscle contraction known as torque depression.. Muscle contraction is what drives human movement. For example, the movement associated with taking a drink involves contraction and shortening of the bicep muscles. This contraction generates a force called torque that causes the forearm to rotate at the elbow towards your mouth, and allows you to enjoy your morning coffee. But not all muscle contractions are created equal. During contractions where the muscle does not shorten, such as holding a travel mug at waist-level between sips, the muscle generates more torque compared to a muscle that had to shorten to match the same position. The lower amount of torque ...
A new wearable microscope enables in vivo monitoring of individual muscle fiber contractions in live humans, a feat that has not been possible despite our longstanding physiological understanding of how muscles contract. According to the report in the December 16 Neuron online, researchers led by senior authors Scott Delp and Mark Schnitzer at Stanford University in Palo Alto, California, have developed a microscope by connecting an infrared light source to a fine needle containing miniaturized optics that is inserted into the muscle. The device can distinguish fast and slow twitch muscles, stimulate muscle contractions, and track changes in properties of the individual contractile units of skeletal muscles, or sarcomeres, that occur due to injury or disease. This compact, portable device could fit on a bedside pushcart, and the researchers hope to ultimately develop it into a clinically useful device for diagnosing neuromuscular diseases and monitoring their progression in human ...
Dear Readers, Audrey is 56 years old and has been experiencing increasing episodes of muscle contractions in her calves and even in her feet at times. The contractions can last from a few seconds to more than 15 minutes. They occur mainly...
THE CONTRACTION AND Relaxation OF CARDIAC FIBERS Through contraction of your coronary heart muscle fiber inside the ventricles, blood enters the arteries that depart the center for the other organs of the physique. After the contraction, the ventricles then take it easy to reduced force and make place for blood from atria. The decreased tension is definitely the diastolic stress from peace when the systolic strain occurs with the contraction of your hearts ventricular muscular tissues.. The center muscle fibers are interconnected and glimpse more such as skeletal muscle. The muscle fiber has both of those the skinny and thick filaments having a tiny sarcoplasmic reticulum. The calcium ions originate from inside and outdoors the cells thus earning the contraction of your cardiac muscle mass fiber actin-regulated . The thin and thick filaments slide using an enhance in calcium ions brought on via the motion potential within the membrane a result of the activation of ATPase with the myosin. Bulk ...
Purpose: To determine the effects of concentric and eccentric muscle contractions on IL-6 signaling and its possible downstream regulation of HSP-72 expression in human skeletal muscle, and whether contraction-induced ...
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The OF studied show marked differences in contractile activity. Whilst CF contract matrix by 55% within the first 24h, the same number of TF only contract it by 10%. Whilst contraction by CF quickly reaches a plateau, TF generate sustained contraction. Final matrix contraction is the same. SF only contract matrix at higher cell density. CF generate the greatest force; TF generate 2/3 less, and SF hardly any. Three main factors determine contraction efficiency: cell volume (CF,TF,SF), cell protrusive and retractile activity (dynamic index, DI), and efficient binding to matrix fibrils. DI mirrors force generation. ML9 reduces DI and force generation. Ilomastat has a modest effect on DI and force, but dramatically inhibit matrix contraction, indicating that additional mechanisms are involved. ...
In a previous communication by one of us (G. B. (1)) it was shown that graded contractions and relaxations of natural form can be obtained in the diaphragm and in skeletal nerve muscle preparation by manipulating a faradic induction apparatus in a special manner. Briefly, this manipulation consists in imparting a smooth to-and-fro movement to the secondary coil of the apparatus, the movement taking place between the points of just maximal and just minimal stimulation. These to-and-fro movements cause certain changes of amplitude in the stimulating current, and the various patterns thus produced are faithfully repeated in the contractions of the experimental muscle, provided the changes are kept within the above-mentioned limiting points. An attempt has been made in the present research to obtain reciprocal contraction of antagonistic muscles by an extension of the above method. In the working-out of the new method of excitation, and in its application to double nerve-muscle preparations, the ...
Delayed-onset muscle soreness (DOMS) describes an entity of ultrastructural muscle damage. The manifestation of DOMS is caused by eccentric muscle contractions or unaccustomed forms of exercise. Clinical signs include impaired muscular force capacities, painful restriction of movement, stiffness, sw …
Approach and Results-Real-time polymerase chain reaction, immunohistochemistry, and Western analyses supported the synthesis and expression of chemerin in perivascular adipose tissue, whereas the primary chemerin receptor ChemR23 was expressed both in the tunica media and endothelial layer. The ChemR23 agonist chemerin-9 caused receptor, concentration-dependent contraction in the isolated rat thoracic aorta, superior mesenteric artery, and mesenteric resistance artery, and contraction was significantly amplified (more than 100%) when nitric oxide synthase was inhibited and the endothelial cell mechanically removed or tone was placed on the arteries. The novel ChemR23 antagonist CCX832 inhibited phenylephrine-induced and prostaglandin F2α-induced contraction (+perivascular adipose tissue), suggesting that endogenous chemerin contributes to contraction. Arteries from animals with dysfunctional endothelium (obese or hypertensive) demonstrated a pronounced contraction to chemerin-9. Finally, ...
DALLAS - Researchers at UT Southwestern Medical Center have identified a previously unrecognized small protein in cells of the human heart that plays a key role in heart muscle contraction. The protein is made from an RNA that was previously believed to be a blank or non-coding RNA, suggesting there may be many other small non-coding segments that play important biological roles. Significantly, the findings published today in Science offer a potential new target for developing therapeutics to boost the strength of cardiac muscle contractions in patients with heart failure, a chronic condition in which the heart pumps too weakly to supply adequate oxygen to the body. The new protein, which the researchers have named dwarf open reading frame (DWORF), comprises just 34 amino acids, making it the third smallest protein known to be encoded in the mouse genome. By comparison, an average-sized protein is 10 times larger, including about 350 amino acids. DWORF is also encoded in the human genome. The ...
You searched for: Creator Karreman, George Remove constraint Creator: Karreman, George Subject Muscle Contraction Remove constraint Subject: Muscle Contraction ...
where Λ is the ratio of muscle length to the optimal length at which maximal isometric tension is produced, and α(Λ) is a function numerically equal to the ratio of the tetanic isometric force to its maximum value. The single dimensionless constant in this relation, B, can be calculated from model parameters characterizing muscle dynamics at the optimum length, and has a value near unity for frog sartorius at 0°C. The predicted behavior is shown to agree reasonably well with experimental measurements of heat production and phosphocreatine (PCr) hydrolysis. The model relates the isometric energy rates to PCr hydrolysis in (1) cross-bridge interactions, and (2) calcium pumping into the sarcoplasmic reticulum.. ...
TY - JOUR. T1 - Muscle activation is enhanced with multi- and uni-articular bilateral versus unilateral contractions. AU - Behm, D.G.. AU - Power, K.E.. AU - Drinkwater, Eric. N1 - Imported on 12 Apr 2017 - DigiTool details were: Journal title (773t) = Applied Physiology, Nutrition and Metabolism. ISSNs: 1066-7814; PY - 2003. Y1 - 2003. N2 - Ten resistance trained (RT) and 6 non-resistance trained (NRT) subjects were used to determine differences in quadriceps activation between isometric single and double knee extensions and squat contractions. Greater inactivation, as measured by the interpolated twitch technique, was recorded with single (RT: 16.5%, NRT: 17.6%) than double leg extensions (RT: 8.4%, NRT: 13.4%) or squats (RT: 4.03%, NRT: 1.7%). There was no significant difference between the maximum voluntary contraction (MVC) force of the dominant leg during single and double leg extensions. However, in NRT subjects, the contralateral or non-dominant leg during double leg extensions exhibited ...
There are a number of factors that increase the risk of a quadriceps strain. For example, high forces across the muscle-tendon units combined with eccentric contraction can lead to strain injury. Excessive passive stretching or activation of a maximally stretched muscle can also cause strains. Muscle fatigue has also been shown to play a role in acute muscle injury(3). This may account for the observation of increased injury risk during the pre-season (when fitness levels tend to be lower, leading to the earlier onset of fatigue). However, of the four bellies, the RF is most frequently strained(4-8). There are a number of factors behind the increased vulnerability of RF; as well as crossing two joints, it contains a high percentage of explosive type-II fibres and also has a complex musculotendinous architecture, all of which are known to increase injury risk(9,10).. As noted in the NCAA study above, indirect trauma occurs for the most part as a result of eccentric contractions(4,11). This can ...
Although the contraction of each muscle cell is all-or non, it is obvious that body movements are not. Sometimes they are forceful, other times slight. This is easily accounted for by realizing that body movements are brought about by whole muscles (groups of muscle cells), not by single cell acting alone. Increasing the force of movement may simply be a matter of recruiting more and more cells into cooperative action. However, there are also more subtle means for changing the performance of individual cells.. The strength or, more precisely, the force a muscle is capable of exerting depends on its length. For each muscle cell, there is an optimum length or range of lengths where the contractile force is strongest. This is easily explained by the sliding fillament theory. The strength of contraction depends on the number of cross bridges that can make contact with actin fillaments. When the muscle is too long, few cross bridges can make contact, and contraction is weak. When the muscle is too ...
Instance of an apostrophe-less contraction is none, which is the contracted type of not one. Others experience cramps, contractions and discomfort for weeks before delivery. The terbutaline did settle down the contractions fairly a bit and there have been only two trips to the hospital with preterm labor scares. I had a number of demanding situations come up and certainly one of them put me into preterm labor where the contractions started to vary the cervix.. Anytime you feel contractions earlier than 37 weeks it is best to let your physician know instantly. For some, Braxton hicks contractions shall be painless, while others will find it more painful and sometimes confused with pre-labor. If you are underneath 37 weeks pregnant and you have greater than 3-4 contractions per hour, please name your doctor straight away.. What Ive observed with the irritable uterus is that if I keep lively, the contractions increase and change into more uncomfortable. Generally these contractions may be ...
Looking for eccentric, contraction muscle? Find out information about eccentric, contraction muscle. the contractile tissue that effects the movement of and within the body. Muscle tissue in the higher animals is classified as striated, smooth, or cardiac,... Explanation of eccentric, contraction muscle
DOMS is the main reason youre slow to get out of bed the next day. Theodore Hough first described this phenomenon in 1902, stating that DOMS is fundamentally the result of ruptures within the muscle.. Dont fret; its not as bad as it sounds. However, his statement still rings mostly true to this day. Research has found that eccentric muscle contractions cause tiny tears to the connective tissue and units of muscle known as myofilaments, which collectively make up a muscle fiber. It is this structural damage to the muscle that causes the pain and tenderness associated with DOMS.. Soreness usually starts around 24 hours after activity and peaks between 48 and 72 hours. From there, it usually dissipates and is gone completely 5 to 7 days after activity. The more strenuous the activity, the longer the soreness will last. Youre more likely to suffer from DOMS if you have taken a long break from exercise and are just getting started back, or, similarly, if you are engaging in physical activity ...
When you have a contraction, your womb tightens and then relaxes. For some people, contractions may feel like extreme period pains. You may have had contractions during your pregnancy, particularly towards the end. These tightenings are called Braxton Hicks contractions and are usually painless.. As labour gets going, your contractions tend to become longer, stronger and more frequent. During a contraction, the muscles tighten and the pain increases. If you put your hand on your abdomen, youll feel it getting harder; when the muscles relax, the pain fades and you will feel the hardness ease.. The contractions are pushing your baby down and opening the entrance to your womb (the cervix), ready for your baby to go through.. Your midwife will probably advise you to stay at home until your contractions become frequent. Call your midwife for guidance when your contractions are in a regular pattern and:. ...
When you have a contraction, your womb tightens and then relaxes. For some people, contractions may feel like extreme period pains. You may have had contractions during your pregnancy, particularly towards the end. These tightenings are called Braxton Hicks contractions and are usually painless.. As labour gets going, your contractions tend to become longer, stronger and more frequent. During a contraction, the muscles tighten and the pain increases. If you put your hand on your abdomen, youll feel it getting harder; when the muscles relax, the pain fades and you will feel the hardness ease.. The contractions are pushing your baby down and opening the entrance to your womb (the cervix), ready for your baby to go through.. Your midwife will probably advise you to stay at home until your contractions become frequent. Call your midwife for guidance when your contractions are in a regular pattern and:. ...
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Inactivation of excitation-contraction coupling was examined in extensor digitorum longus (EDL) and soleus muscle fibers from rats injected daily with tri-iodothyronine (T3, 150 micrograms/kg) for 10-14 d. Steady-state activation and inactivation curves for contraction were obtained from measurements of peak potassium contracture tension at different surface membrane potentials. The experiments tested the hypothesis that noninactivating tension is a window tension caused by the overlap of the activation and inactivation curves. Changes in the amplitude and voltage dependence of noninactivating tension should be predicted by the changes in the activation and inactivation curves, if noninactivating tension arises from their overlap. After T3 treatment, the area of overlap increased in EDL fibers and decreased in soleus fibers and the overlap region was shifted to more negative potentials in both muscles. Noninactivating tension also appeared at more negative membrane potentials after T3 ...
Only a few words and phrases about rhythmic contraction and comfort of cardiovascular system lean muscle in helpful coming up with Rhythmic contraction and
We explain Muscle Contractions: Macro View with video tutorials and quizzes, using our Many Ways(TM) approach from multiple teachers.|p|This lesson will give an overview of how a specific muscle contracts to allow movement in the body. |/p|
How to Stop Muscle Twitches. Muscle twitches are caused by small contractions in either a part of a muscle or a whole muscle. They can occur in any muscle in the body but often occur in the limbs, eyelids, or diaphragm. They are typically...
TY - JOUR. T1 - Twitch potentiation after voluntary contraction and neuromuscular electrical stimulation at various frequencies in human quadriceps femoris. AU - Miyamoto, Naokazu. AU - Fukutani, Atsuki. AU - Yanai, Toshimasa. AU - Kawakami, Yasuo. PY - 2012/1/1. Y1 - 2012/1/1. N2 - Introduction: In this study we aimed to compare the extent of twitch potentiation (TP) after voluntary contraction and percutaneous electrical stimulation of muscles (neuromuscular electrical stimulation: NMES) with various stimulation frequencies at equivalent target levels. Methods: Isometric knee extensions of 10 s were performed at a 40% maximal voluntary contraction level by voluntary or NMES conditioning contractions at 20, 40, and 80 H Z of the quadriceps femoris muscle. Twitch responses were elicited by stimulating the femoral nerve transcutaneously at supramaximal intensity. Results: NMES at 80 HZ induced significantly less TP (128.7 ± 17.1%) than voluntary contraction (156.2 ± 23.1%), whereas no ...
Fatigue in muscles that shorten might have other causes than fatigue during isometric contractions, since both cross-bridge cycling and energy demand are different in the two exercise modes. While isometric contractions are extensively studied, the causes of fatigue in shortening contractions are poorly mapped. Here, we investigate fatigue mechanisms during shortening contractions in slow twitch skeletal muscle in near physiological conditions. Fatigue was induced in rat soleus muscles with maintained blood supply by in situ shortening contractions at 37°C. Muscles were stimulated repeatedly (1 s on/off at 30 Hz) for 15 min against a constant load, allowing the muscle to shorten and perform work. Fatigue and subsequent recovery was examined at 20 s, 100 s and 15 min exercise. The effects of prior exercise were investigated in a second exercise bout. Fatigue developed in three distinct phases. During the first 20 s the regulatory protein Myosin Light Chain-2 (slow isoform, MLC-2s) was rapidly ...
TY - JOUR. T1 - Rapamycin administration in humans blocks the contraction-induced increase in skeletal muscle protein synthesis. AU - Drummond, Micah J.. AU - Fry, Christopher. AU - Glynn, Erin L.. AU - Dreyer, Hans C.. AU - Dhanani, Shaheen. AU - Timmerman, Kyle L.. AU - Volpi, Elena. AU - Rasmussen, Blake. PY - 2009. Y1 - 2009. N2 - Muscle protein synthesis and mTORC1 signalling are concurrently stimulated following muscle contraction in humans. In an effort to determine whether mTORC1 signalling is essential for regulating muscle protein synthesis in humans, we treated subjects with a potent mTORC1 inhibitor (rapamycin) prior to performing a series of high-intensity muscle contractions. Here we show that rapamycin treatment blocks the early (1-2 h) acute contraction-induced increase (∼40%) in human muscle protein synthesis. In addition, several downstream components of the mTORC1 signalling pathway were also blunted or blocked by rapamycin. For instance, S6K1 phosphorylation (Thr421/Ser424) ...
TY - JOUR. T1 - Dynamic imaging of skeletal muscle contraction in three orthogonal directions. AU - Lopata, R.G.P.. AU - Dijk, van, J.P.. AU - Pillen, S.. AU - Nillesen, M.M.. AU - Maas, H.. AU - Thijssen, J.M.. AU - Stegeman, D.F.. AU - Korte, de, C.L.. PY - 2010. Y1 - 2010. N2 - In this study, a multidimensional strain estimation method using biplane ultrasound is presented to assess local relative deformation (i.e., local strain) in three orthogonal directions in skeletal muscles during induced and voluntary contractions. The method was tested in the musculus biceps brachii of five healthy subjects for three different types of muscle contraction: 1) excitation of the muscle with a single electrical pulse via the musculocutaneous nerve, resulting in a so-called twitch contraction; 2) a train of five pulses at 10 Hz and 20 Hz, respectively, to obtain a submaximum tetanic contraction; and 3) voluntary contractions at 30, 60, and 100% of maximum contraction force. Results show that biplane ...
The object of this research is to compare the reflex contractions of the cruralis muscle in the decerebrate and spinal frog in response to a single break induction shock, applied to the ipsilateral sciatic nerve. Sherrington (5) studied the limb reflexes in the decerebrate and spinal cat. He showed that in the decerebrate preparation the reflex contraction of an extensor muscle was accompanied by an autogenous tonic reflex which prolonged the contraction. This autogenous tonic reflex was absent from the reflex contractions of the flexors in the decerebrate, and from the extensors in the decapitate, preparations. Sherrington (5) and Sherrington and Sowton (6) showed that in the spinal cat the reflex contraction of the tibialis anticus muscle was higher and had a more rapid ascent than in the decerebrate cat. Sherrington concluded that the mid-brain exercises an inhibitory influence over the flexor limb centres in the cord. Head (2) arrived at similar conclusions in stating that, on removal of ...
Key points Muscle glycogen (the storage form of glucose) is consumed during muscle work and the depletion of glycogen is thought to be a main contributor to muscle fatigue. In this study, we used a novel approach to first measure fatigue-induced reductions in force and tetanic Ca2+ in isolated single mouse muscle fibres following repeated contractions and subsequently quantify the subcellular distribution of glycogen in the same fibre. Using this approach, we investigated whether the decreased tetanic Ca2+ induced by repeated contractions was associated with glycogen depletion in certain subcellular regions. The results show a positive correlation between depletion of glycogen located within the myofibrils and low tetanic Ca2+ after repetitive stimulation. We conclude that subcellular glycogen depletion has a central role in the decrease in tetanic Ca2+ that occurs during repetitive contractions. In skeletal muscle fibres, glycogen has been shown to be stored at different subcellular locations: ...
Hypotheses were tested that a muscle stimulated at a frequency that elicited a maximal rate of force development (dP/dto) was fully activated during after-loaded isotonic contractions by the time the muscle developed the force necessary to displace the after-load and consequently the shortening velocity was maximum. whereas a muscle stimulated at a rate that elicited maximum tetanic force (Po) was not fully activated and under similar circumstances could not displace after-loads at maximum velocities. As controls for fully activated muscle, the same muscles were stimulated to develop Po and were then released to each after-load. Soleus muscles from 14 mice were stimulated directly in vitro at 25º C. Shortening velocities of each muscle were measured at 13 different after-loads using 4 different protocols: stimulation at a frequency that produced Po (approximately 90 Hz) with an after-loaded isotonic contraction: stimulation at 90 Hz to Po with a quick-release to each after-load; stimulation at ...
TY - JOUR. T1 - Pressor reflex response to static muscular contraction. T2 - Its afferent arm and possible neurotransmitters. AU - Kaufman, Marc. AU - Rotto, Diane M.. AU - Rybicki, Kenneth J.. PY - 1988/9/9. Y1 - 1988/9/9. N2 - Static muscular contraction has been shown to increase cardiovascular and ventilatory function in reflex manner. The sensory arm of this reflex arc is comprised of group III and IV muscle afferents. The discharge properties of these muscle afferents whose activation causes the pressor reflex response to contraction were investigated. Group III afferents were more responsive to mechanical stimuli, such as tendon stretch and probing their receptive fields than were group IV afferents. In contrast, group III afferents were less responsive to ischemic contraction than were group IV afferents. Equal percentages of group III and IV afferents were stimulated by potassium, lactic acid and arachidonic acid, each of which are metabolic products of contraction. Adenosine, phosphate ...
Most athletes stretch as part of their training regimen and it is commonly believed that this practice prevents muscle injury. We tested this belief using an animal model, in situ mouse extensor digitorum longus (EDL) muscle. One lower hindlimb was slowly stretched for 1 min on alternate days for 12 days; the other leg served as a control. The mouse was lightly anaesthetized during the stretching protocol (isofluorane). Both legs were tested in situ by measuring maximum isometric force and Show moreMost athletes stretch as part of their training regimen and it is commonly believed that this practice prevents muscle injury. We tested this belief using an animal model, in situ mouse extensor digitorum longus (EDL) muscle. One lower hindlimb was slowly stretched for 1 min on alternate days for 12 days; the other leg served as a control. The mouse was lightly anaesthetized during the stretching protocol (isofluorane). Both legs were tested in situ by measuring maximum isometric force and maximum ...
Enhanced muscle weakness is commonly experienced following stroke and may be accompanied by increased susceptibility to fatigue. To examine the contributions of central and peripheral factors to isometric muscle fatigue in stroke survivors, this study investigates changes in motor unit (MU) mean firing rate and action potential duration during, and directly following, a sustained submaximal fatiguing contraction at 30% maximum voluntary contraction (MVC). A series of short contractions of the first dorsal interosseous muscle were performed pre- and postfatigue at 20% MVC, and again following a 10-minute recovery period, by twelve chronic stroke survivors. Individual MU firing times were extracted using surface EMG decomposition and used to obtain the spike-triggered average MU action potential waveforms. During the sustained fatiguing contraction, the mean rate of change of the firing rate across all detected motor units was greater on the affected side (-0.02 ± 0.03 Hz/s) than on the less-affected
Correcting for insufficient power because of weak uterine contractions: During labour, regular palpation of the womans abdomen is done to assess strength of contractions. Insufficient contraction strength is a common reversible cause of dystocia, and acting to intervene by augmenting contraction strength with oxytocin can prevent or readily correct a state of dystocia if this is the reason for it. Very often it is the cause of dystocia. If abdominal palpation +/- tocometry suggests insufficient uterine contractions, then augmenting contractions with oxytocin may be warranted. In some cases, uterine contractions may seem strong, or there may be confounding factors making assessment of contraction strength difficult to do (ex: maternal obesity). In these cases, confirmation of weak contractions by an intrauterine pressure catheter may be useful. An intrauterine pressure catheter (IUPC) is the only accurate way of assessing the intensity (in mm Hg) of contractions, but it is more invasive and not ...
TY - JOUR. T1 - Vascular smooth muscle contraction induced by Na+ channel activators, veratridine and batrachotoxin. AU - Shinjo(H), Masayoshi. AU - Toshio, Nakaki. AU - Yukari, Otsuka. AU - Nobuyuki, Sasakawa. AU - Ryuichi, Kato. PY - 1991/11/26. Y1 - 1991/11/26. N2 - The effects of the sodium channel activators veratridine and batrachotoxin on isolated rat aorta were investigated. Veratridine caused gradual contraction, independent of the presence of endolhelium, with an EC50 of 35 μM. Batrachotoxin (1 μM) also induced contraction. Both effects were completely inhibited by the sodium channel blocker tetrodotoxin (1 μM). The veratridine (60 μM)-induced contraction was inhibited by nifedipine (0.1 μM). In the absence of extracellular Ca2+, veratridine (60 μm) did not cause contraction. Sodium nitroprusside (80 nM), acetylcholine (10 μM) and isoproterenol (1 μM) caused relaxation of rings precontracted with veratridine (60 μM). An inhibitor of endothelium-derived relaxing factor (EDRF) ...
Background: The magnitude of the hyperemic response due to repeated thigh stump exercise on incremental contraction intensity might be useful information in localized exercise tolerance for devising cardiovascular physical therapy for amputees. The effect of exercise on amputated leg blood flow (LBF) may potentially be altered due to voluntary muscle contractions after loss of the lower leg compared with the healthy leg. Case Presentation: A 57-year-old male patient with Burger disease attempted 3 min unilateral repeat/dynamic knee extensor exercise at a target muscle contraction frequency (1 s thigh muscle contraction and 1 s relaxation, 90 repetitions) with each leg at six different contraction intensities (rubber resistance belt). Simultaneous measurement of blood velocity/flow (Doppler ultrasound) in the femoral artery, blood pressure, leg vascular conductance (LVC), and peak muscle strength (PMS) were performed during the 3 min exercise period. The maximum voluntary contraction by one-legged
TY - JOUR. T1 - Postcontraction discharge of motor neurons in spinal animals. AU - Hutton, Robert S.. AU - Suzuki, Shuji. PY - 1979. Y1 - 1979. N2 - Muscle contraction of short duration gives rise to prolonged enhanced activity in muscle spindle afferent fibers. This postcontraction sensory discharge is sufficient in intensity to frequency-modulate motor neurons demonstrated to be tightly coupled to stretch receptors of the activated muscle. To determine whether or not postcontraction activation of motor neurons is dependent on supraspinal pathways, further experiments were done on cats with low spinal (T12) lesions. Sixty-one motor neurons were isolated in ventral root filaments and categorized according to their stretch reflex response and discharge pattern. Units found to be facilitated by stretch were significantly increased (P , 0.01) in resting discharge following contraction. Phasic motor neurons responded with a short postcontractile burst lasting only a few seconds whereas tonically ...
When the contractile properties of single muscle fibres are studied, force is typically normalized by fibre cross-sectional area and expressed as specific force. We studied a set of 2725 chemically skinned human single muscle fibres from 119 healthy adults to determine whether specific force is the optimal way to express the relationship between single-fibre force and size. A linear mixed effects model was used to estimate the slope and slope variability among individuals of log-log plots of force and diameter. For type I fibres, the slope estimate was 0.99 (95% confidence interval 0.36-1.62), and for type IIa fibres it was 0.94 (95% confidence interval 0.77-1.11), indicating that force is proportional to fibre diameter, rather than to cross-sectional area. If force were proportional to cross-sectional area, the slope estimate would be 2.0. In future studies using the chemically skinned single fibre preparation, force may be normalized to fibre diameter rather than cross-sectional area. We ...
TY - JOUR. T1 - Number of contractions to maintain mass and force of a denervated rat muscle. AU - Dow, Douglas E.. AU - Cederna, Paul S.. AU - Hassett, Cheryl A.. AU - Kostrominova, Tatiana. AU - Faulkner, John A.. AU - Dennis, Robert G.. PY - 2004/7. Y1 - 2004/7. N2 - Within 5 weeks, denervated extensor digitorum longus (EDL) muscles of rats lose 66% of mass, 91% of force, and 76% of fiber cross-sectional area (CSA). We previously determined the parameters of electrical stimulation for denervated rat EDL muscles to generate tetanic contractions sufficient to maintain mass and force close to control values. Using these parameters, we tested the hypothesis that a range exists for number of contractions per day, below and above which values for mass, maximum force, and fiber CSA are lower than values for innervated control muscles. For 5 weeks, denervated EDL muscles were stimulated to generate between 25 and 5000 contractions daily with contractions separated by constant intervals of rest, ...
The ability of a muscle to shorten and produce force is crucial for locomotion, posture, balance and respiration. During a contraction, myosin heads on the myosin filament propel the actin filament via ATP hydrolysis, resulting in shortening of the muscle and/or force generation. The maximal shortening velocity of a muscle fibre is largely determined by the myosin ATPase activity, while maximal force is primarily determined by the cross-sectional area. Since most muscles are pennate rather than parallel-fibred and work at different lever ratios, muscle architecture and joint-tendon anatomy has to be taken into account to obtain the force and velocity characteristics of a muscle. Additionally, the recruitment of agonistic and antagonistic muscles will contribute to the torque generated during a contraction. Finally, tendon compliance may impact on the rate of force rise and force generated if it is such that the muscle contraction proceeds in the ascending limb of the length-tension relation. ...
Post-activation potentiation (PAP) is a well-described phenomenon with a short half-life (~28 s) that enhances muscle force production at submaximal levels of calcium saturation (i.e., submaximal levels of muscle activation). It has been largely explained by an increased myosin light chain phosphorylation occurring in type II muscle fibers, and its effects have been quantified in humans by measuring muscle twitch force responses to a bout of muscular activity. However, enhancements in (sometimes maximal) voluntary force production detected several minutes after high-intensity muscle contractions are also observed, which are also most prominent in muscles with a high proportion of type II fibers. This effect has been considered to reflect PAP. Nonetheless, the time course of myosin light chain phosphorylation (underpinning
Airway Smooth Muscle Contraction Hyperresponsiveness to mast cell-derived mediators (eg, histamine) is a distinctive feature of asthma, but its etiology is
Various exercises require a predominance of certain muscle fiber utilization over another. Aerobic exercise involves long, low levels of exertion in which the muscles are used at well below their maximal contraction strength for long periods of time (the most classic example being the marathon). Aerobic events, which rely primarily on the aerobic (with oxygen) system, use a higher percentage of Type I (or slow-twitch) muscle fibers, consume a mixture of fat, protein and carbohydrates for energy, consume large amounts of oxygen and produce little lactic acid. Anaerobic exercise involves short bursts of higher intensity contractions at a much greater percentage of their maximum contraction strength. Examples of anaerobic exercise include sprinting and weight lifting. The anaerobic energy delivery system uses predominantly Type II or fast-twitch muscle fibers, relies mainly on ATP or glucose for fuel, consumes relatively little oxygen, protein and fat, produces large amounts of lactic acid and can ...
Contractile properties of skeletal muscle are studied for various purposes and mainly by means of force or torque twitch responses. This study compared contractile properties estimated from isometric longitudinal and transversal vastus lateralis twitch mechanical actions using torque and tensiomyography (TMG) as assessment methods, respectively. We calculated delay, contraction, sustain, half relaxation time and peak amplitude from the maximal twitch response obtained by both methods in 19 healthy males (age 46.1±17.8 years). Results indicated a shorter delay (Δ=-23.4%; p,.001) and contraction time (Δ=-42.7%; p,.001) when calculated from the transversal tensiomyographic actions, and shorter half relaxation time (Δ=-26.2%; p=.025) when calculated from the longitudinal torque actions, while no difference in sustain time was found. Delay and contraction time did not correlate significantly when correlated between longitudinal and transversal actions; however, sustain time (r=.478; p=.038) and ...
Exercise is often recommended as a means of improving motor skills, fitness, muscle and bone strength, and joint function. Exercise has several effects upon muscles, connective tissue, bone, and the nerves that stimulate the muscles. Various exercises require a predominance of certain muscle fiber utilization over another. Aerobic exercise involves long, low levels of exertion in which the muscles are used at well below their maximal contraction strength for long periods of time (the most classic example being the marathon). Aerobic events, which rely primarily on the aerobic (with oxygen) system, use a higher percentage of Type I (or slow-twitch) muscle fibers, consume a mixture of fat, protein and carbohydrates for energy, consume large amounts of oxygen and produce little lactic acid. Anaerobic exercise involves short bursts of higher intensity contractions at a much greater percentage of their maximum contraction strength. Examples of anaerobic exercise include sprinting and weight lifting. ...
Isotonic Contraction: In an isotonic contraction, the tension within the muscle remains the same throughout the motion, which is to say the force of the contraction remains constant. This is also called the positive portion of an exercise movement. There are two aspects of isotonic contraction, concentric, and eccentric. Concentric contraction occurs when the muscle fibers shorten as tension develops. At the onset of the movement, the actin and myosin filaments have tremendous pulling force. Thus you will be stronger in the initial phase of most movements. Toward the end or near the peak of contraction, the ability of the filaments to slide toward each other reaches a limit and strength weakens. An eccentric contraction is the type of muscle contraction that involves lengthening the muscle fibers, such as when a weight is lowered through a range of motion. The muscle yields to the resistance, allowing itself to be stretched. Here the actin and myosin slide away from each other. The level of ...
Thirty-six male subjects from collegiate intramural athletic teams were asked to maintain 50% of their maximum voluntary contraction on an isometric hand dynamometer as long as possible. The subjects were divided into two groups. One group performed individually while the other group, in teams of three men each, competed for a team prize. During the session, the active muscle was continuously monitored by electromyography. The results demonstrated that the introduction of the motivational factors of competition and team presence did not increase the mean endurance time. The EMG analyses indicated that muscle activity was significantly increased when additional motivational factors were introduced. It was concluded that team presence and competition are better described as stress factors which increase the general arousal level of the subject and reduce the efficiency of the muscles. (Author)(*MUSCLES
A 10-wk supplementation period with beta-alanine in adult rats caused a substantial increase in muscle carnosine and anserine levels. The increases were more pronounced for carnosine than for anserine and also more pronounced in oxidative (soleus and red gastrocnemius) than in glycolytic (white gastrocnemius) muscles. These nutritionally induced metabolic changes were accompanied by several, generally beneficial, adaptations in contractile function in MUs of the rat gastrocnemius. BA supplementation improved the twitch force of FF units and the maximum tetanic force of FR units and prolonged the half-relaxation time in slow units. As expected, it reduced the fatigability of FF units but only during the first 10 s after initiation of repeated fatiguing activity. Moreover, it enhanced the force potentiation of FR units normally observed during a standard fatigue test. Finally, supplementation reduced force decline of slow units during the first minute of repeated contractions evoked by ...
There is accumulating evidence, both in extracranial10 11 19 20 and in intracranial9 21 arteries, that TBA results in sustained arterial dilatation through a mechanism of smooth muscle cell injury and paralysis. This is consistent with other evidence that vasospasm represents active smooth muscle cell contraction22 and that it can be acutely reversed in the presence of vasodilators such as papaverine.23 24 The results of our study suggest that in vivo balloon angioplasty performed immediately before the induction of vasospasm prevents vasoconstriction after SAH and produces a functional impairment in vascular reactivity that is sustained for at least 7 days. These results are consistent with our previous report on the effects of immediate in vitro TBA9 and those of others investigating in vivo TBA performed after SAH.10 11 21 High millimolar concentration of KCl produces smooth muscle cell contraction through electromechanical coupling mechanisms with depolarization of the sarcolemma,25 whereas ...
Although smooth muscle contraction relies on the presence of Ca++ ions, smooth muscle fibers have a much smaller diameter than skeletal muscle cells. T-tubules are not required to reach the interior of the cell and therefore not necessary to transmit an action potential deep into the fiber. Smooth muscle fibers have a limited calcium-storing SR but have calcium channels in the sarcolemma (similar to cardiac muscle fibers) that open during the action potential along the sarcolemma. The influx of extracellular Ca++ ions, which diffuse into the sarcoplasm to reach the calmodulin, accounts for most of the Ca++ that triggers contraction of a smooth muscle cell.. Muscle contraction continues until ATP-dependent calcium pumps actively transport Ca++ ions back into the SR and out of the cell. However, a low concentration of calcium remains in the sarcoplasm to maintain muscle tone. This remaining calcium keeps the muscle slightly contracted, which is important in certain tracts and around blood ...
Mutungi, GM and Ranatunga, KW (1998) Effects of reducing sarcomere length on twitch contraction in mammalian (rat) muscle fibres. The Journal of Physiology, 511.P. pp. 155-156. ISSN 1469-7793 Full text not available from this repository. (Request a copy ...
A really time efficient and worthwhile type of exercise to add to your arsenal is static contraction training. Along with visualized resistance, which we have spoken of before, or with either weight training or, in my opinion the better option of bodyweight exercise, static contractions can increase your strength fast, conveniently, and effectively. ...
The vascular smooth muscle cell (VSMC) is a highly specialized cell whose principal function is contraction. On contraction, VSMCs shorten, thereby decreasing the diameter of a blood vessel to regulate the blood flow and pressure. The principal mechanisms that regulate the contractile state of VSMCs are changes in cytosolic Ca2+ concentration ([Ca2+]c). In response to vasoconstrictor stimuli, Ca2+ is mobilized from intracellular stores and/or the extracellular space to increase [Ca2+]c in VSMCs. The increase in [Ca2+]c, in turn, activates the Ca2+-CaM-MLCK pathway and stimulates MLC20 phosphorylation, leading to myosin-actin interactions and, hence, the development of contractile force. The sensitivity of contractile myofilaments or MLC20 phosphorylation to Ca2+ can be secondarily modulated by other signaling pathways. During receptor stimulation, the contractile force is greatly enhanced by the inhibition of myosin phosphatase. Rho/Rho kinase, PKC, and arachidonic acid have been proposed to ...
The vascular smooth muscle cell (VSMC) is a highly specialized cell whose principal function is contraction. On contraction, VSMCs shorten, thereby decreasing the diameter of a blood vessel to regulate the blood flow and pressure. The principal mechanisms that regulate the contractile state of VSMCs are changes in cytosolic Ca2+ concentration ([Ca2+]c). In response to vasoconstrictor stimuli, Ca2+ is mobilized from intracellular stores and/or the extracellular space to increase [Ca2+]c in VSMCs. The increase in [Ca2+]c, in turn, activates the Ca2+-CaM-MLCK pathway and stimulates MLC20 phosphorylation, leading to myosin-actin interactions and, hence, the development of contractile force. The sensitivity of contractile myofilaments or MLC20 phosphorylation to Ca2+ can be secondarily modulated by other signaling pathways. During receptor stimulation, the contractile force is greatly enhanced by the inhibition of myosin phosphatase. Rho/Rho kinase, PKC, and arachidonic acid have been proposed to ...
Figure 13 Ratio of fast type FG and FOG to slow type SO fibres in different type athletes In muscle contraction individual types of muscle fibres get activated in accordance with the intensity of muscle movement. About Podcast Contact. Leave a reply Cancel reply You must be logged in to post a comment. It is important to note here that the fibre ratio differs in different muscles of the human body. All muscle cells have a little ATP within them that they can use immediately - but only enough to last for about 3 seconds! The energy for ATP resynthesis comes from three different series of chemical reactions that take place within the body. This process creates enough energy to couple with the energy requirements to resynthesize ATP. Regardless, sport-specific conditioning plans and optimal nutritional intake need to be implemented. After maximum power declines around 12 seconds, further intense activity up to approximately 30 seconds results in lactic acid accumulation, a decrease in power, and ...
The skeletal muscles are the effector organs of the locomotor system. They are under voluntary control. Skeletal muscle is described usually as striated muscle because of its striped microscopic appearance, which results from the ordered and regular arrangement of the sub-cellular contractile elements. The stimulus for physiological skeletal muscle activity is always derived from a nerve impulse,and transported in the form of action potential, through the nervous system to the motor neuron that innervates the muscle fiber. Muscle contraction results from the interaction of actin and myosin, two filamentous proteins in the muscle cell. Energy for contraction is accumulated in the cell, and produced by aerobic and anaerobic processes during muscle contractions. This paper describes structure of skeletal muscle, and explains mechanisms of skeletal muscle contraction. It is dealing also with energy production, and muscle fatigue as well ...
Some parameters of rhythmic mechanical and electrical events of guinea-pig gall-bladder were investigated. Pressure-volume (P-V) responses, extracellular electrical activity and gall-bladder morphology were recorded. Rhythmic gall-bladder activity consisted of waves of pressure at intraluminal volumes between 0.5 and 1.8 ml. The pressure waveforms developed in a single contraction were usually oscillatory, containing two or more peaks which were more or less separated. The maximum amplitude value of phasic pressure waves was 1.8 +/- 0.6 cmH2O. Bursts of spike potentials appeared at three equidistant electrodes along the longitudinal diameter of the bladder with variable delays indicating absence of propagation of the fast electrical activity. By analysing the morphological changes of gall-bladder silhouette during the P-V curve it was evident that the maximum amplitude and duration of contractile events occurred when the whole muscular wall was stretched. Tetrodotoxin added to the bath solution did not
When training in plyometrics you need to accelerate though a complete range of motion, followed by a relaxation into a full stretch. In other words, plyometric movements require you to load your muscle then contracted in rapid sequence. You quickly stretch the muscle you are working during the initial push-off. This is thought to increase muscle contraction, thus increasing power generation.. For movement to occur a muscle must shorten which is known as concentric contraction. However, there is a maximum amount of force or limit to which the muscle can concentrically contract. Now if the muscle can be lengthened while being loaded (i.e. eccentric phase) just prior to the muscle contraction, it will produce a greater force though the storage of elastic energy. That is, the time between the two phases, (concentric contraction and eccentric phases) must be very short.. Plyometric exercises develop explosive power due to this quick release of energy by the muscles. However, plyometrics should not be ...
TY - JOUR. T1 - Changes in end-to-end interactions of tropomyosin affect mouse cardiac muscle dynamics. AU - Gaffin, Robert D.. AU - Gokulan, Kuppan. AU - Sacchettini, James C.. AU - Hewett, Timothy E.. AU - Klevitsky, Raisa. AU - Robbins, Jeffrey. AU - Sarin, Vandana. AU - Zawieja, David C.. AU - Meininger, Gerald A.. AU - Muthuchamy, Mariappan. PY - 2006. Y1 - 2006. N2 - The ends of striated muscle tropomyosin (TM) are integral for thin filament cooperativity, determining the cooperative unit size and regulating the affinity of TM for actin. We hypothesized that altering the α-TM carboxy terminal overlap end to the β-TM counterpart would affect the amino-terminal association, which would alter the end-to-end interactions of TM molecules in the thin filament regulatory strand and affect the mechanisms of cardiac muscle contraction. To test this hypothesis, we generated transgenic (TG) mouse lines that express a mutant form of α-TM in which the first 275 residues are from α-TM and the last ...
Birba A, Hesse E, Sedeño L, Mikulan EP, García MDC, Ávalos J, Adolfi F, Legaz A, Bekinschtein TA, Zimerman M, Parra M, García AM, Ibáñez A. Enhanced Working Memory Binding by Direct Electrical Stimulation of the Parietal Cortex. Front Aging Neurosci. 2017 Jun 8;9:178. doi: 10.3389/fnagi.2017.00178 La memoria de trabajo de integración (WMB) es un marcador preclínico de la enfermedad de Alzheimer (EA) que depende de regiones posteriores del cerebro. La estimulación de la corteza parietal posterior (PPC) podría ser un target terapéutico en la EA. En este estudio, encontramos que la estimulación eléctrica y directa intracraneal de regiones específicas de la PPC durante la WMB induce una mejora selectiva en el desempeño.
Autor: Borchers, S et al.; Genre: Zeitschriftenartikel; Im Druck veröffentlicht: 2012-01; Titel: Direct electrical stimulation of human cortex: the gold standard for mapping brain functions?
BioAssay record AID 71785 submitted by ChEMBL: Percent block of sciatic nerve sartorius muscle twitch of frog 60 min after indirect stimulation and exposure to 50 uM toxin for 60 min.
Dynamic force generation in cardiac muscle, which determines cardiac pumping activity, depends on both the number of sarcomeric cross-bridges and on their cycling kinetics. The Frank-Starling mechanism dictates that cardiac force development increase
New research involving people diagnosed with Lou Gehrigs disease sheds light on how individual neurons control muscle movement in humans - and could help in the development of better brain-controlled prosthetic devices.
Airway smooth muscle (ASM) contraction is a major contributor to bronchoconstriction, the narrowing of the airways observed in asthmatic airways. In vitro, ASM cells demonstrate the capacity to switch between more proliferative and more contractile phenotypes, and changes to ASM contractile function, potentially as a consequence of this phenotypic switching, may play a significant role in the exaggerated airway narrowing observed in asthma. In vivo, airway epithelial (AE) cells are topographically close to the ASM and may modulate and regulate ASM phenotype and function that could be dysregulated in asthma. One important mediator increased in asthma is TGF-β1, which influences AE cell phenotype and thus possibly affects AE cell effects on ASM. In this work, we investigated the effects of AE, with and without the influence of TGF- β1, on ASM contractile function. After examining the response of AE and ASM to TGF-β1 individually, one-way and two-way communication modes between the cell types ...
Purpose: The purpose of this study was to investigate the origins of differing tonic muscle activity in three populations with known differences in neuromuscular processing. Methods: We manipulated healthy young adults, healthy older adults and individuals with Parkinsons disease (PD), both on and off dopamine therapy medication, with a novel technique related to muscle after contraction (MAC). We also investigated the transfer of tonic activity to the contralateral (unmanipulated) limbs to determine whether tonic activity is modulated through inhibitory and facilitatory interneuronal processes at a peripheral, spinal, or supraspinal level. In independent trials, we examined MAC in both proximal (medial deltoid) and distal (tibialis anterior) postural musculature by having subjects perform a voluntary, isometric contraction of the upper arm or ankle, respectively. Using surface electromyography (sEMG) to record the activity of the motor units before, during and after contraction, we were able ...
Currently I am looking into what muscles groups are most used during a football kick. I have a hypothesis that the quadriceps are not as used as most people think because the momentum the swing creates makes the knee extend to fast for the quadriceps to contract.. To prove this I need to know the speed the knee extends during a football kick and the time it takes for the quadriceps to contract. I know how fast the knee extends through my own research. Does anyone have any information on the speed of muscle contraction? Quadriceps contraction time would be optimal, but any information relevant would be very helpful. ...
A nonwoven web material that includes an elastic component or material (e.g., nonwoven web, nonwoven web laminated to an elastic material, etc.) is provided. The elastic component contains a crosslinked network formed from a pentablock copolymer containing at least two monoalkenyl aromatic midblocks positioned between conjugated diene endblocks, such as butadiene-styrene-butadiene-styrene-butadiene (
Contraction of muscles generates tension, which allows muscles to shorten and thereby perform work.The contraction strength of skeletal muscles must be
Mechanically skinned fibre preparations from the extensor digitorum longus muscle of the rat were used to test whether a rise in myoplasmic [NH+4] in the range 2-10 mM interferes with the mechanism of excitation-contraction coupling in fast-twitch mammalian muscle. Under our conditions (pH 7.10, Mg2+ 1 mM, temperature 23 degrees C), [NH+4] up to 10 mM had little effect on the Ca(+)-activated force and on the peak of the t-system depolarization-induced force response. However, the duration of the depolarization-induced force response was decreased significantly at [NH+4] > or = 2 mM. From these data we conclude that the intracellular accumulation of NH+4 is not likely to play a major role in fatigue. Nevertheless, the build up of NH+4 during fatigue, may have a significant inhibitory effect on the force output by decreasing the duration of the t-system depolarization-induced activation of the contractile apparatus ...
Slower contractions can also occur which might lead to constipation. Abnormal contractions can be due to improper functioning of the muscles or due to improper signals from the nervous system that control these contractions.. The trigger for these can be food, stress or even hormonal changes. Food such as milk, alcohol may lead to the IBS symptoms to worsen in some people. Stress is another major cause, which can aggravate symptoms of the IBS. Hormones can lead to worsening of the symptoms as many women find exacerbation of IBS during their menstrual periods.. ...
Psychogenic hypothesis: emotions, such as stress, causing contraction in skeletal muscles. The vertebral subluxation has been ... muscle contraction or imbalance; altered physiological function; reversible with adjustment/manipulation; focal tenderness. ... Most of these go to muscles and are therefore called motor impulses; some are secretory and enter glands; a portion are ...
... heart muscle contraction performance; and some aspects of heart valve function. Important internal heart and lung blood ... Less frequently, valvular, heart muscle, or arrhythmia issues are the primary focus of the test. Coronary artery luminal ...
... involuntary contractions may involve the muscles used for chewing (masticatory muscles). These may include the thick muscle in ... temporalis muscle). Some patients may also experience involuntary contractions of the wide muscle at the side of the neck ( ... platysmal muscle). This muscle draws down the corner of the mouth and lower lip or other muscle groups. In some cases Meige's ... The Greek word blepharon means "eyelid". Spasm means "uncontrolled muscle contraction". The term blepharospasm ['blef-a-ro-spaz ...
Spudich JA, Huxley HE, Finch J (1972). "Regulation of skeletal muscle contraction. II. Structural studies of the interaction of ... Spudich JA, Watt S (1971). "The Regulation of Rabbit Skeletal Muscle Contraction". Journal of Biological Chemistry. 246 (15): ... of Biochemistry and of Cardiovascular Disease at Stanford University and works on the molecular basis of muscle contraction. He ... A brief history of muscle biology 1864-1969". Retrieved 2 June 2020. Zubrinic, Darko. "James Spudich American scientist of ...
The muscles then contract through the sliding filament mechanism, causing shortening of sarcomeres and muscle contraction. ... Webb RC (December 2003). "Smooth muscle contraction and relaxation". Advances in Physiology Education. 27 (1-4): 201-6. doi: ... When these cells are depolarized, the L-type calcium channels open as in smooth muscle. In skeletal muscle, the actual opening ... "Thromboxane A2-induced contraction of rat caudal arterial smooth muscle involves activation of Ca2+ entry and Ca2+ ...
Webb, RC (December 2003). "Smooth muscle contraction and relaxation". Advances in Physiology Education. 27 (1-4): 201-6. doi: ... Directly relax the muscle in the walls of the blood vessels (especially the arterioles), allowing the vessel to dilate (widen ... However, it has been shown that knocking out this sympathetic stimulation plays little or no role in whether skeletal muscle is ... It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, ...
Muscle contraction is stimulated by the motor neuron sending a message to the muscles from the somatic nervous system. ... Cardiac muscles are found in the heart and are used only to circulate blood; like the smooth muscles, these muscles are not ... Bárány, Michael (2002). "SMOOTH MUSCLE". Retrieved 19 November 2008. "The Mechanism of Muscle Contraction". Principles of Meat ... Skeletal muscles are attached to bones and arranged in opposing groups around joints. Muscles are innervated, to communicate ...
... high levels of epinephrine causes smooth muscle relaxation in the airways but causes contraction of the smooth muscle that ... Arnall DA, Marker JC, Conlee RK, Winder WW (June 1986). "Effect of infusing epinephrine on liver and muscle glycogenolysis ... stimulates glycogenolysis in the liver and muscle,[37] and stimulates glycolysis and inhibits insulin-mediated glycogenesis in ... It plays an important role in the fight-or-flight response by increasing blood flow to muscles, output of the heart, pupil ...
Muscle contraction. References[edit]. *^ a b c d e f Hong, TingTing; Shaw, Robin M. (2017-01-01). "Cardiac T-Tubule ... excitation-contraction coupling). When contraction of a muscle is needed, stimulation from a nerve or an adjacent muscle cell ... They are found in ventricular muscle cells in most species, and in atrial muscle cells from large mammals.[4] In cardiac muscle ... Excitation-contraction coupling[edit]. See also: Excitation-contraction coupling. T-tubules are an important link in the chain ...
Main article: Muscle contraction. Multiple myosin II molecules generate force in skeletal muscle through a power stroke ... Myosin II (also known as conventional myosin) is the myosin type responsible for producing muscle contraction in muscle cells ... Myosins (/ˈmaɪəsɪn, -oʊ-/[1][2]) are a superfamily of motor proteins best known for their roles in muscle contraction and in a ... The MLC20 is also known as the regulatory light chain and actively participates in muscle contraction.[16] ...
Muscle contractionEdit. The nervous system and musculoskeletal system control the majority of mammalian motility. ... Skeletal muscle is the type of muscle you use to move, e.g. the bicep and triceps move the lower arm. Skeletal muscles are ... As the muscles run out of ATP, the muscle fibres become permanently contracted and lock solid. This produces a stiffening ... Muscles give the ability for voluntary movement, and involuntary movement as in muscle spasms and reflexes). At the level of ...
Is titin a 'winding filament'? A new twist on muscle contraction. Kiisa C Nishikawa, Jenna A Monroy, Theodore E Uyeno, Sang ... "NAU physiologist publishes findings on the role of the protein titin in muscle contraction - NAU News". Retrieved 2020-03-07. " ... where her laboratory investigates muscle contraction, including the role of titin and developing bio-inspired control ... Nishikawa is the principal investigator leading the Muscle and Motor Control Laboratory at Northern Arizona University (NAU), ...
This increases the muscle contraction strength. Additionally, within minutes, cell metabolism and gene expression, which are ... In this phase of the cardiac cycle, electrical signals cannot trigger new cardiac muscle contractions, hence this type of ... The short- and long-term use of this therapy enhances the strength of ventricular contraction and therefore the heart's pumping ... Studies on individual cardiac muscle cells using a patch-clamp technique had already shown, in 1969, that a voltage applied ...
"Structural changes in muscle during contraction; interference microscopy of living muscle fibres". Nature. 173 (4412): 971-973 ... leading to the sliding filament model of muscle contraction. Interference microscopy became relatively popular in the 1940-1970 ... which was first effectively exploited by Andrew Huxley in studies of striated muscle cell structure and function, ...
Smooth muscle contraction in the gut. Probable role in sleep paralysis. Activation of the 5-HT2A receptor is necessary for the ...
... which cause the contraction of skeletal muscles. These equations presented an entirely new paradigm for understanding muscle ... into a detailed description of muscle structure and how muscle contraction occurs and generates force that he published in 1957 ... "Structural changes in muscle during contraction; interference microscopy of living muscle fibres". Nature. 173 (4412): 971-3. ... He, however, was able to make interference microscopy work and to apply it to the problem of muscle contraction with great ...
Chapman, RA (January 1980). "Excitation-contraction Coupling in Cardiac Muscle". Progress in Biophysics and Molecular Biology. ... which are then transmitted to cardiac muscle cells to induce contraction. After depolarization, the ions are moved back to ... Mutations resulting in loss of function of K+ channels can result in delayed repolarization of the cardiac muscle cells. ... and cardiac muscle, to mutations in genes coding for ion channels of the heart. Movement of ions, particularly Na+, Ca2+ and K+ ...
Sliding Filament Mechanism in Muscle Contraction. Advances in Experimental Medicine and Biology. 565. pp. 283-92, discussion 92 ... ALC-1 is expressed very early in skeletal muscle and cardiac muscle development; two E-boxes and CArG box in the MYL4 promoter ... ALC-1 is expressed in fetal cardiac ventricular and fetal skeletal muscle, as well as fetal and adult cardiac atrial tissue. ... ALC-1 is expressed in fetal cardiac ventricular and fetal skeletal muscle, as well as fetal and adult cardiac atrial tissue. ...
... 's role in muscle contractionEdit. The helical F-actin filament found in muscles also contains a tropomyosin molecule, a ... Outline of a muscle contractionEdit. In muscle cells, actomyosin myofibrils make up much of the cytoplasmic material. These ... Both actin and myosin are involved in muscle contraction and relaxation and they make up 90% of muscle protein.[136] The ... In metazoan muscle cells, to be the scaffold on which myosin proteins generate force to support muscle contraction. ...
Cardiac muscle relaxation. *Smooth muscle contraction. *cardioprotective in cardiac ischemia. *inhibition of neutrophil ...
A 0 is for no muscle contraction. A 1 is for a flicker or trace of contraction in a muscle. A 2 is for active movement in a ... muscle strength is tested using the bench press for a variety of spinal cord related injuries with a muscle being assessed on a ... In 2002, USA Track & Field defined this class as, "These athletes have no hand function, are unable to use the muscles that ... The sixth test measures the trunk extension involving the lumbar and dorsal muscles while leaning forward at a 45 degree angle ...
This event allows the muscle fibers to overlap, causing a contraction. In BD, Ca2+ levels are high in the cytoplasm, which ... Skeletal muscle biopsies are used to examine muscle fibers. Biopsies in individuals with BD often show variation in muscle ... Increases in cytoplasmic Ca2+ levels interfere with muscle contraction, leading to the characteristic symptoms of BD. In some ... "Sliding Filament Theory, Sarcomere, Muscle Contraction, Myosin , Learn Science at Scitable". www.nature.com. Retrieved 2018-09- ...
... that are integral to muscle contraction in skeletal muscle and cardiac muscle, but not smooth muscle. Measurements of cardiac- ... and contraction of the muscle begins. Troponin is found in both skeletal muscle and cardiac muscle, but the specific versions ... playing the main role in Ca2+ dependent regulation of muscle contraction. TnT and TnI in cardiac muscle are presented by forms ... In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing contraction. When the ...
He attributed this muscle contraction to irritability, which he described as being an inherent power. He particularly made the ... One example is the muscle and contraction. Various explanations on a macroscopic and microscopic scale were made to explain how ... and differences in muscles across living things and his understanding of the underlying mechanism of muscle contraction, ... thus the muscle changed shape at a fixed volume by only changing the angles between each fibre. This explanation of contraction ...
For example, it regulates the contraction of muscles, nerve conduction, and the clotting of blood. As a result, intra- and ... in contraction of all muscle cell types; as cofactors in many enzymes; and in fertilization. Calcium ions outside cells are ... Symptoms include anorexia, nausea, vomiting, memory loss, confusion, muscle weakness, increased urination, dehydration, and ...
vascular permeability; vascular smooth muscle contraction; allergy. antagonists of CYSLTR1 used in asthma as well as other ... vascular permeability; vascular smooth muscle contraction; allergy. antagonists of CYSLTR1 used in asthma as well as other ... platelet aggregation, vascular smooth muscle contraction. PGI2 analogs used to treat vascular disorders like pulmonary ...
Davydov, Alexander S. (1979). "Solitons, bioenergetics, and the mechanism of muscle contraction". International Journal of ... Davydov, Alexander S. (1973). "The theory of contraction of proteins under their excitation". Journal of Theoretical Biology. ...
Structural basis of contraction in vertebrate smooth muscle. J Mol Biol. 1972 Jun 14; 67(1):117-149. Squire JM. General model ... The main focus of his research was on the structural basis of muscle contraction. His early contributions were the proposal of ... His final works were on the unresolved problem of how myosin and actin molecules interact to bring about muscle contraction, as ... where he researched muscle contraction and blood vessel glycocalyx structure. He was a Fellow of both the Institute of Physics ...
For example, botulinum injections paralyze facial muscles. This prevents muscle contraction and subsequent wrinkle formation. ...
EMS units are designed to cause muscle contraction. An increasing number of "body toner" or "electromassage"-type power sources ... The international standard on the basic safety of medical nerve and muscle stimulators advises "that stimulation should not be ... electrical muscle stimulation) units. Some people soon found alternative uses for the Relax-A-Cizors by placing the contacts on ... which was originally designed to stimulate the muscles of a relaxing subject using electric currents as a means of "passive ...
... and he thought there was reason to believe that the sudden contraction of muscle is produced by its combination with other ... and is further formed by the combination of these two sets of particles in muscle during violent exertion. In effect, therefore ... combustible (salino-sulphureous) particles in the body; hence the heart, being a muscle, ceases to beat when respiration is ...
... of muscle strength in hibernating bears is the occurrence of periodic voluntary contractions and involuntary contractions from ... Muscle atrophy is defined as a decrease in the mass of the muscle; it can be a partial or complete wasting away of muscle, and ... Moreover, starvation eventually leads to muscle atrophy. Disuse of the muscles, such as when muscle tissue is immobilized for ... Muscle atrophy can be opposed by the signaling pathways which induce muscle hypertrophy, or an increase in muscle size. ...
Gaddum as a tissue extract that caused intestinal contraction in vitro.[5] Its tissue distribution and biologic actions were ... muscle, and joints. It is proposed that this release is involved in neurogenic inflammation, which is a local inflammatory ... muscle, and joints. It is proposed that this release is involved in neurogenic inflammation, which is a local inflammatory ... was isolated from porcine spinal cord and was also found to stimulate intestinal contraction.[7] ...
Duration- the amount of time from the start of a contraction to the end of the same contraction. Intensity- a measure of how ... The fetal heart rate and the activity of the uterine muscle are detected by two transducers placed on the mother's abdomen (one ... Frequency- the amount of time between the start of one contraction to the start of the next contraction. ... the amount of time between the end of one contraction to the beginning of the next contraction. The NICHD nomenclature defines ...
So there's just over 2×1018 kg of water vapor. 1 g of liquid water has a volume of 1 cm³, so 1 kg has a volume of 1 L, and so 2 ... If you have to muscle the steering wheel around when the motor is not running, but it moves easily when the motor is running, ... Here are some primary sources (some more recent than others, be sure to contextualize each with its date--there's a lot more ... Do electrons flow differently in a wire than in a circuit? Here's what I gathered. ...
The ingress of water is achieved by contraction of radial muscles in the mantle wall, and flapper valves shut when strong ... The infundibulum provides adhesion while the acetabulum remains free, and muscle contractions allow for attachment and ... which involves symmetrical contractions of muscles in their webs producing peristaltic waves. This moves the body slowly.[31] ... Once the shell is penetrated, the prey dies almost instantaneously, its muscles relax, and the soft tissues are easy for the ...
"Assessing patients effectively: Here's how to do the basic four techniques". Nursing2014. 8 (2): 6. 2006.. ... Sports medicine deals with the treatment and prevention and rehabilitation of sports/exercise injuries such as muscle spasms, ... muscle tears, injuries to ligaments (ligament tears or ruptures) and their repair in athletes, amateur and professional. ...
... begins with the contraction of the muscles attached to the rib cage; this causes an expansion in the chest cavity. ... Trapezius muscle. Hyperinflation[edit]. Hyperinflation or hyperaeration is where the lung volume is abnormally increased, with ... Then takes place the onset of contraction of the diaphragm, which results in expansion of the intrapleural space and an ...
Muscle mass[edit]. Males typically have more skeletal muscle mass than females. Androgens promote the enlargement of skeletal ... preventing premature uterine contractions in pregnancy.[16] ... "Androgen receptor in human skeletal muscle and cultured muscle ... muscle cells and probably act in a coordinated manner to function by acting on several cell types in skeletal muscle tissue.[8] ... One cell type conveys hormone signals to generating muscle, the myoblast. Higher androgen levels lead to increased expression ...
... muscle contraction, and heart function.[231] Disruption of this balance may thus be fatal: for example, ingestion of large ... The stabilisation of ununennium's valence electron and thus the contraction of the 8s orbital cause its atomic radius to be ... This trend is broken in francium due to the relativistic stabilisation and contraction of the 7s orbital, bringing francium's ...
... many of the muscles expand into the limb pockets during contraction).[89] ... Some turtles, such as the Indian flapshell (Lissemys punctata), have a sheet of muscle that envelops the lungs. When it ... The difficulty is that most turtle shells are rigid and do not allow for the type of expansion and contraction that other ... By using a series of special muscles (roughly equivalent to a diaphragm), turtles are capable of pushing their viscera up and ...
... "cannot be captured in a description of neural activity or of muscle activation...."[171] The bearing of timing experiments upon ... "There's No Such Thing as Free Will". The Atlantic.. External links[edit]. Listen to this article (info/dl ... these authors also found that awareness of action was anticipatory to activity in the muscle underlying the movement; the ...
Voluntary contraction of the abdominal muscles aids the expulsion of urine by increasing the pressure applied to the urinary ... Gradually, however, the muscle of the "decentralized bladder" becomes active, with many contraction waves that expel dribbles ... Voiding can also be consciously interrupted once it has begun, through a contraction of the perineal muscles. The external ... of the muscles of the pelvic floor causes a sufficient downward tug on the detrusor muscle to initiate its contraction.[14] ...
The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, for ... Muscle spindles are stretch receptors within the body of a muscle that primarily detect changes in the length of the muscle. ... Muscle spindles are found within the belly of muscles, between extrafusal muscle fibers.[b] The specialised fibers that ... Activation of the neurons causes a contraction and stiffening of the end parts of the muscle spindle muscle fibers. ...
This information may be the muscle contraction sequence for shoe-tying, the face of a loved one, or anything in between. When ...
As a result, the muscle cells contract permanently, the communication between the brain and the muscles is disrupted and ... Once it has triggered a contraction, anatoxin-a does not allow the neurons to return to their resting state, because it is not ... Stimulation of these receptors causes a muscular contraction. The anatoxin-a molecule is shaped so it fits this receptor, and ... The nerve tissues which communicate with muscles contain a receptor called the nicotinic acetylcholine receptor. ...
cardiac muscle cell action potential involved in contraction. • calcium ion transmembrane transport. • camera-type eye ... regulation of cardiac muscle contraction by regulation of the release of sequestered calcium ion. • positive regulation of ... It depolarizes at -30mV and helps define the shape of the action potential in cardiac and smooth muscle.[8] The protein encoded ... voltage-gated calcium channel activity involved in cardiac muscle cell action potential. • high voltage-gated calcium channel ...
... which help to anchor and pull the worm via longitudinal muscle contractions. Earthworms have no lungs, and absorb oxygen ...
The final biological response (e.g. second messenger cascade, muscle-contraction), is only achieved after a significant number ... In some receptor systems (e.g. acetylcholine at the neuromuscular junction in smooth muscle), agonists are able to elicit ...
Strong impulses allow for fast recognition of stimulus and allow for muscle contraction (Deen & Hark 2007). Helps with blood ... Calcium regulates the transmutation of nerve impulses for muscle contractions. ... Assists in functionality of muscle construction and nerve impulses - ...
Individual muscle fiber ratios can be determined through a muscle biopsy. Other considerations are the ability to recruit ... an isometric contraction). Manual calculations are usually performed using the top-down analysis on a six or seven-link model, ... Where, Sj is the muscle strength moment at joint, j, and Mj/L is the external moment at the joint, j, due to load, L and the ... Skeletal muscles produce reactive forces and moments at the joints. To avoid injury or fatigue, when person is performing a ...
Tapping the tendon stretches the thigh muscle, which activates stretch receptors within the muscle called muscle spindles. Each ... By inhibiting the flexor, these interneurons aid contraction of the extensor.. *Still other branches of the I-a axons synapse ... Muscle spindles and the stretch reflex[edit]. The knee jerk is the popularly known stretch reflex (involuntary kick of the ... Some of the branches of the I-a axons synapse directly with alpha motor neurons.These carry impulses back to the same muscle ...
Eccentric contraction may result in delayed onset muscle soreness however; the contraction itself does not cause muscle damage ... Muscle injury[edit]. Eccentric contractions are a frequent cause of muscle injury when engaging in unaccustomed exercise. But a ... Perceived muscle damage: There is a stipulation regarding eccentric contractions in that they actually cause muscle damage and ... Eccentric contraction and oxygen consumption: Oxygen consumption is needed for muscles to work properly. Eccentric muscle ...
Blockade of post-synaptic α2 receptors causes only minor corpus cavernosum smooth muscle relaxation, due to the fact that the ... Kaumann AJ (June 1983). "Yohimbine and rauwolscine inhibit 5-hydroxytryptamine-induced contraction of large coronary arteries ... α1 receptors on the corpus cavernosum smooth muscle. Under physiologic conditions, however, nitric oxide attenuates ... "Further characterization of 5-hydroxytryptamine receptors (putative 5-HT2B) in rat stomach fundus longitudinal muscle" ...
cardiac muscle contraction. • muscle cell cellular homeostasis. • neuromuscular process controlling posture. • locomotory ... striated muscle contraction. • glucose metabolic process. • neutrophil degranulation. • carbohydrate metabolic process. Sources ... regulation of the force of heart contraction. • diaphragm contraction. • heart morphogenesis. • maltose metabolic process. • ... Muscle & Nerve. Supplement. 3: S61-9. doi:10.1002/mus.880181414. hdl:1765/66923. PMID 7603530.. ...
Muscle contraction happens because of chemical messages made by nerves of that muscle. By learning how the body functions ...
This likely means contraction of the transversus abdominis, as contraction of the rectus abdominis would cause the back to ... A bent-over row (or barbell row) is a weight training exercise that targets a variety of back muscles.[1] Which ones are ... Muscle hypertrophy. Weightlifting. Plyometrics. Weight training (List of exercises). Gym. Legend. (c) - compound exercise, (i ... Upper back muscles often have a lot of slow-twitch fibers so bent-over rows can respond better than some exercises that use ...
Contraction of the ampullae causes the podia to stretch as water is brought into them. This whole process allows for movement, ... In the absence of ampullae, water pressure is maintained by the ring canal, which is surrounded by contractile muscle fibres.[ ... Instead, a simple valve at the upper end of the foot helps to control water pressure in the tube feet, along with contraction ... Echinoderms move by alternately contracting muscles that force water into the tube feet, causing them to extend and push ...
Sometimes, these signals can cause other involuntary muscle contractions such as body movements and vocalization. Finally, ... chemicals are released in the brain and motor signals are activated that will cause quick cycles of muscle contraction in the ...
At the end of the tracing, distortion results from muscle contractions due to a (short) hypoxic seizure. Because decreased ... The other end of a pacemaker lead is actually implanted into the heart muscle. In addition leads that have been implanted for a ... Most commonly, the generator is placed below the subcutaneous fat of the chest wall, above the muscles and bones of the chest. ... Sometimes the leads, which are small diameter wires, from the pacemaker to the implantation site in the heart muscle will need ...
Create healthcare diagrams like this example called Muscle Contraction in minutes with SmartDraw. SmartDraw includes 1000s of ... Muscle Contraction. Cross-sections of the muscle, showing muscle fibers and their microscopic anatomy.. Biceps while arm is ... Muscle Contraction. Create healthcare diagrams like this example called Muscle Contraction in minutes with SmartDraw. SmartDraw ... The muscle in a. relaxed state.. The muscle is contracted.. LifeART Collection Images Copyright © 1989-2001 by Lippincott ...
... a group of rare muscle contraction disorders characterized by pain and fatigue. ... blocks channels for sodium ions in muscle cells, leading to a reduction in muscle contraction rate and stiffness. ... Cite this: CHMP Backs Antiarrhythmic for Muscle-Contraction Disorders - Medscape - Oct 19, 2018. ... a group of inherited muscle contraction disorders.. This would be the first treatment authorized EU-wide for this rare ...
Thank you for your interest in spreading the word about Science.. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.. ...
Muscle Contraction : Biochemical Aspects of Sportive Practice was designed to promote the association... ... Muscle Contraction: Android app (10+ downloads) → The software ... Muscle Contraction "Muscle Contraction : Biochemical Aspects of Sportive Practice" is an e-book! ... The software Muscle Contraction : Biochemical Aspects of Sportive Practice was designed to promote the association between ...
The active ingredient appears to be nitrate, which somehow reduces the oxygen cost of muscle contractions. How does this happen ... and even the contractile properties of the muscle fibers themselves. ... Why, then, was there no effect on voluntary muscle contractions? When you use electricity to make a muscle twitch, youre just ... Beets Boost Muscle Contraction. Nitrate in your food makes muscle fibers twitch harder. ...
... been possible for the first time to record equatorial and meridional X-ray reflexions from striated muscle during contraction ... FOR some time X-ray diffraction techniques have been used to study living muscle in the resting state1-4. Using a modified ... Memories of early work on muscle contraction and regulation in the 1950s and 1960s *Hugh E. Huxley ... ELLIOTT, G., LOWY, J. & MILLMAN, B. X-ray Diffraction from Living Striated Muscle during Contraction. Nature 206, 1357-1358 ( ...
In contrast, a muscle contraction is isotonic if muscle tension remains the same throughout the contraction. If the muscle ... The mechanisms of contraction in these muscle tissues are similar to those in skeletal muscle tissues. Muscle contractions can ... This occurs when a muscles force of contraction matches the total load on the muscle. In concentric contraction, muscle ... muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle ...
encoded search term (Muscle Contraction Tension Headache) and Muscle Contraction Tension Headache What to Read Next on Medscape ... Muscle Contraction Tension Headache. Updated: May 21, 2019 * Author: Syed M S Ahmed, MD; Chief Editor: Tarakad S Ramachandran, ... Muscle contraction (tension) headache. Clin J Pain. 1989. 5(1):39-44. [Medline]. ... Hypoalgesic effect of caffeine in experimental ischemic muscle contraction pain. Headache. 1997 Nov-Dec. 37(10):654-8. [Medline ...
In contrast, during isometric and eccentric contraction, when is small, then. In this connection it is of interest to consider ... 3. Poorly Understood Phenomena in Muscle Contraction. Because muscle contraction is due to the action of a very large ensemble ... muscle fiber) and in parallel over the muscle fiber cross-section. During muscle contraction, globular myosin motor domains ( ... Further, eccentric contraction, when the muscle is stretched during activity, is associated with work done on the muscle rather ...
... in heart muscle releases a large amount of Ca2+ in response to a small amount of trigger Ca2+ by the mechanism of the Ca2+- ... Regulation of Contraction in Heart Muscle. A Ca2+ Gradient Model for the Ca2+-Induced Ca2+-Release of the Sarcoplasmic ... This interprets the effects of beat frequency and external [Ca2+] on twitch contractions in intact heart muscle. The present Ca ... Tameyasu T. (1998) Regulation of Contraction in Heart Muscle. In: Sugi H., Pollack G.H. (eds) Mechanisms of Work Production and ...
... Our heart and skeletal muscles contain intricately organized cells that generate the ... Structural changes in muscle during contraction; interference microscopy of living muscle fibers. Nature. 173:971-973. Huxley, ... in powering contraction. To account for their observations, both groups surmised that muscle contraction was not caused by A- ... Muscle Contraction and Sliding Filaments. For Biophysics Week, members of the Early Careers Committee have written short ...
Isolytic contraction is when a muscle contracts while external forces cause it to lengthen. For example, during a controlled ... lowering of the weight in a biceps curl, the biceps are undergoing isolytic contraction. In osteopathic manipulative medicine, ...
... this is a comprehensive account of the theory of muscle contraction, in parallel with exciting experimental discoveries of the ... The first book to provide a unified description of the mathematics of muscle contraction, ... Understanding the molecular mechanism of muscle contraction started with the discovery that striated muscle is composed of ... The Sliding-Filament Theory of Muscle Contraction. Authors. * David Smith Copyright. 2018. Publisher. Springer International ...
Optically controlled contraction of photosensitive skeletal muscle cells.. Asano T1, Ishizua T, Yawo H. ... It also induced a twitch-like contraction in a concurrent manner. A contraction pattern was thus made with a given pattern of ... As the skeletal muscle cell is an efficient force transducer, it has been incorporated in bio-microdevices using electrical ... This technique would have many applications in the bioengineering field, such as wireless drive of muscle-powered actuators/ ...
Muscle Contraction - Download as Powerpoint Presentation (.ppt), PDF File (.pdf), Text File (.txt) or view presentation slides ... no more than 10 kg of muscle (,1/3 the total muscle mass) can be fully active at any one time. . the blood flow in 1 kg of ... the muscle must rid itself of metabolic products such as H+. Muscle work therefore requires drastic cardiovascular and ... Excessive physical exercise causes muscle soreness and stiffness. which leads to muscle swelling and pain. . The underlying ...
Contraction of Cardiac & Smooth Muscle • Although significant differences exist, the basic mechanism in both muscle types ... Types of Skeletal Muscle Fiber • 1. Red muscle fibers • a. Slow twitch, fatigue resistant • - Splits ATP slowly; rich blood ... Contraction of Skeletal Muscle • 1. A nerve signal triggers the release of • acetylcholine into neuromuscular synapse. • 2. ... 3. Most skeletal muscles in the body have a mixture of all three fiber types in various • proportions depending on the muscle ...
Nitric oxide, reactive oxygen species, and skeletal muscle contraction.. Reid MB1. ... the processes whereby endogenous ROS modulate contraction of unfatigued muscle, and 3) the site(s) of action and reversibility ... whereby NO and ROS regulate contraction. This review article provides a personal perspective on the processes regulated by NO ... modulate contractile function of respiratory and limb skeletal muscle. The intracellular processes regulated by NO and ROS ...
... Oleg S. Matusovsky. ,1. ,. 2 Olga Mayans. ,3 and Danuta ... showed that during muscle contraction force and calcium transients are not changing in parallel and that a change in steady- ... Molecular Mechanism of Muscle Contraction: New Perspectives and Ideas. View this Special Issue. ... pointed out the poorly understood aspects of striated muscle contraction and, in particular, the relationship between the force ...
Muscle power output and the steady rate of contraction are linked by modulating a single parameter, a viscosity coefficient. ... Muscle operation is characterized by working strokes of much shorter length and much quicker than in the classical model. As a ... as the tendency of these proteins to form geometrically ordered structures provide a link between water and muscle contraction ... to the stiffness of muscle structures and to the viscosity of the sliding of the thin over the thick filaments. ...
Cardiac Muscle resembles skeletal muscle in its structure and in regulation of actin-myosin interactions and muscle contraction ... Smooth Muscle[edit]. Actin and myosin are much less organized in smooth muscle when compared to skeletal muscle. Smooth muscle ... Skeletal Muscle[edit]. A motor nerve action potential spreads down transverse tubules and then passes to the sarcoplasmic ... Troponin/Tropomyosin Regulate Contraction[edit]. Myosin and Actin invitro binds and hydrolyzes ATP, even in the absence of Ca2+ ...
... also called shortening contraction, and eccentric, in which the length actually increases during contraction.. When both muscle ... also called shortening contraction, and eccentric, in which the length actually increases during contraction.. When both muscle ... It is known as co-contraction, and helps to steady or stabilize.. In technical terms, there are two types of contraction: ... It is known as co-contraction, and helps to steady or stabilize.. In technical terms, there are two types of contraction: ...
eccentric, contraction muscle synonyms, eccentric, contraction muscle pronunciation, eccentric, contraction muscle translation ... contraction muscle. brawn; power; force; organ that produces movement Not to be confused with: mussel - a bivalve mollusk or ... contraction muscle: isometric muscle contraction, isotonic muscle contraction, concentric muscle contraction ... striated muscle tissue - muscle tissue characterized by transverse stripes. cardiac muscle, heart muscle - the muscle tissue of ...
Triclosan impairs excitation-contraction coupling and Ca2+ dynamics in striated muscle Message Subject (Your Name) has sent you ... Triclosan impairs excitation-contraction coupling and Ca2+ dynamics in striated muscle. Gennady Cherednichenko, Rui Zhang, ... 1982) Slow inward calcium currents have no obvious role in muscle excitation-contraction coupling. Nature 298:292-294. ... 1995) Raised intracellular [Ca2+] abolishes excitation-contraction coupling in skeletal muscle fibres of rat and toad. J ...
The inherent compliance of soft fluidic actuators makes them attractive for use in wearable devices and soft robotics. Their flexible nature permits them t
... in a chemical reaction with water provides energy for skeletal muscles to contract. Since the amount of... ... How do your muscle cells produce ATP during rapid exercise?. A: Muscle cells produce ATP anaerobically during periods of rapid ... such as muscle contraction, transmission of nerve... Full Answer , Filed Under: * Tennis ... metabolic pathways that generate new ATP must be activated for continued muscle contraction. These pathways are either ...
Heres how scientists did it. How Close Are W... ... but growing ones that can make muscles move? Thats an ... which are even capable of eliciting coordinated muscle contractions in co-cultured mouse spinal cord-muscle explants. This ... Growing brains can be a tricky process, but growing ones that can make muscles move? Thats an incredible feat. Heres how ... Focal Point S1 • E2 Were Close to a Universal Quantum Computer, Heres Where Were At - Duration: 8:36. Seeker 3,432,396 views ...
SEARCH RESULTS for: Decreased Striated Muscle Contraction [Drug Class] (16 results) * Share : JavaScript needed for Sharing ...
... but not for eccentric muscle contractions. Just over a decade ago, we discovered that eccentric contractions were associated ... but not for eccentric muscle contractions. Just over a decade ago, we discovered that eccentric contractions were associated ... Therefore, we propose that muscle contraction involves three filaments, actin, myosin and titin, and that titin regulates force ... Therefore, we propose that muscle contraction involves three filaments, actin, myosin and titin, and that titin regulates force ...
When a muscle cell contracts, the molecules create and release bonds between the thick and thin filaments, which ratchet along ... A relaxed muscle generally means that there is not an intentional or voluntary contraction of the muscle fibers. If someone is ... Muscle Contractions. When a muscle cell contracts, the molecules create and release bonds between the thick and thin filaments ... contraction following a concentric contraction and maintaining an isometric contraction following an eccentric contraction. ...
The vascular smooth muscle cell (VSMC) is a highly specialized cell whose principal function is contraction. On contraction, ... Vascular smooth muscle contraction [ Pathway menu , Organism menu , Pathway entry , Download KGML , Show description , User ...
  • In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding a heavy book or a dumbbell at the same position. (wikipedia.org)
  • This has become known as the Fenn effect in muscle physiology. (frontiersin.org)
  • The importance of the tensor tympani muscle in middle-ear physiology remains unclear. (nih.gov)
  • UT Southwestern s Dr. Kristine Kamm (left), associate professor of physiology, Dr. Yusuke Mizuno, postdoctoral researcher, and Dr. James Stull, chairman of physiology, analyze data from recent experiments investigating how smooth-muscle cells contract. (innovations-report.com)
  • Understanding the underlying chemical signals involved in this process may have implications in treating conditions such as hypertension and other smooth muscle related conditions where there is too much contractile activity," said Dr. James Stull, chairman of physiology at UT Southwestern and senior author of the study. (innovations-report.com)
  • Ouedraogo N, Roux E (2014) Physiology of Airway Smooth Muscle Contraction: An Overview. (omicsonline.org)
  • It is believed that imaging of mechanical response of contracting muscles can contribute to a more explicit study of muscle physiology and a more dexterous method for prosthetic control.Two different experiments were executed during this study, one for determining the time delay between ECG electrode and ultrasound response and one for imaging muscle activity during an isometric contraction. (bibsys.no)
  • Not exactly about my father's PhD students, but I did get him to write a historical piece on his early years diffracting x-rays off contracting muscle (early 60s) for Physiology News (sorry, large PDF). (occamstypewriter.org)
  • The model was found to fit the data well, and the values of the parameters were apparently consistent with smooth muscle physiology, or plausible explanations could be postulated for their values. (illinois.edu)
  • Muscle contraction is the activation of tension-generating sites within skeletal muscle fibers. (wikipedia.org)
  • The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state. (wikipedia.org)
  • A single motor neuron is able to innervate multiple muscle fibers, thereby causing the fibers to contract at the same time. (wikipedia.org)
  • In eccentric contraction, the tension generated while isometric is insufficient to overcome the external load on the muscle and the muscle fibers lengthen as they contract. (wikipedia.org)
  • Cross-sections of the muscle, showing muscle fibers and their microscopic anatomy. (smartdraw.com)
  • Nitrate in your food makes muscle fibers twitch harder. (runnersworld.com)
  • There are a number of overlapping theories related to blood circulation, neurotransmission, and even the contractile properties of the muscle fibers themselves. (runnersworld.com)
  • There have been some studies of nitrate and muscle fibers in mice, but this one uses real live humans. (runnersworld.com)
  • interference microscopy of living muscle fibers. (biophysics.org)
  • Although significant differences exist, the basic mechanism in both muscle types involves interactions between actin and myosin similar to those in skeletal fibers. (scribd.com)
  • A body tissue composed of elongated cells (called muscle fibers) that contract to produce movement. (thefreedictionary.com)
  • However, a good understanding of how muscle contraction occurs seemed only possible once microscopy techniques had evolved to a level where basic structural features, such as the regular cross striation patterns of fibers, could be observed in the late 19th century. (frontiersin.org)
  • As more and more muscle fibers contract, they attempt to shorten the entire muscle by sliding the attachment points at the two ends of the muscle toward each other. (humankinetics.com)
  • All of the fibers do not have to contract at the same time, meaning that a muscle can generate a precisely gradated amount of force, coordinated by the dialogue between the nervous system and the muscles. (humankinetics.com)
  • Because muscles work in this modulated way, they don't always end up shortening, even though the fibers might be actively contracting. (humankinetics.com)
  • Concentric Contraction The muscle fibers contract and generate more force than the resistance that is present so that the ends of the muscle slide toward each other and the muscle shortens. (humankinetics.com)
  • Eccentric Contraction The muscle fibers contract and generate less force than the resistance that is present so that the ends of the muscle slide apart and the muscle actually lengthens. (humankinetics.com)
  • Isometric Contraction The muscle fibers contract and generate the same amount of force as the resistance that is present so that the ends of the muscle neither move apart nor move together and the length of the muscle does not change. (humankinetics.com)
  • A relaxed muscle generally means that there is not an intentional or voluntary contraction of the muscle fibers. (humankinetics.com)
  • If someone is conscious (even sleeping), however, there is always an underlying level of automatic activity in the muscle fibers to maintain the resting tone of the muscle. (humankinetics.com)
  • During this muscle movement, your muscle fibers are stretched under tension from a force greater than the muscle generates. (healthline.com)
  • Concentric contractions are muscle movements that shorten your muscle fibers when performing an action. (healthline.com)
  • Though the term 'contraction' implies a shortening or reduction, when used as a scientific term referring to the muscular system contraction refers to the generation of tension by muscle fibers. (wikidoc.org)
  • This can be achieved in two ways: (1) by increasing the number and size of contractile unites simultaneously, called multiple fiber summation, and (2) by increasing the frequency at which action potentials are sent to muscle fibers, called frequency summation. (wikidoc.org)
  • Frequency Summation - For skeletal muscles , the force exerted by the muscle is controlled by varying the frequency at which action potentials are sent to muscle fibers. (wikidoc.org)
  • Action potentials do not arrive at muscles synchronously, and during a contraction some fraction of the fibers in the muscle will be firing at any given time. (wikidoc.org)
  • Typically when a human is exerting a muscle as hard as they are consciously able, roughly one-third of the fibers in that muscle will be firing at once, but various physiological and psychological factors (including Golgi tendon organs and Renshaw cells ) can affect that. (wikidoc.org)
  • This 'low' level of contraction is a protective mechanism to prevent avulsion of the tendon - the force generated by a 100% contraction of all fibers is sufficient to damage the body. (wikidoc.org)
  • Cross-bridge Formation Detected by Stiffness Measurements in Single Muscle Fibers. (buecher.de)
  • Non Cross-bridge Stiffness in Skeletal Muscle Fibers at Rest and During Activity. (buecher.de)
  • cross sectional area of the muscle (higher CSA , higher strength) -type I and II fiber area -myosin heavy chain isoforms present in type II fibers -angle of pinnation - various metabolic factors , but is very important to understand that those factors affect more endurance than max-strength. (biology-online.org)
  • To image muscle activity in a sequence of ultrasound strain rate images, the probe were placed in a clamped and fixed position over the biceps, giving images perpendicular to muscle fibers. (bibsys.no)
  • It would not be practical for all the fibers in a given muscle to contract every time the motoneuron discharged an action potential. (fitclick.com)
  • Therefore, before the motoneuron reaches the target muscle, it divides into many separate branches that independently activate groups of muscle fibers. (fitclick.com)
  • The number of fibers per motor unit depends on the specific muscle. (fitclick.com)
  • A small muscle used for intricate movements will have less than 100 fibers per motor unit and less than 100 motor units in total. (fitclick.com)
  • A large muscle used for weight-bearing and propulsion will have several thousand fibers per motor unit and several hundred motor units. (fitclick.com)
  • 3. Histochemical studies of the CTM show that individual muscle fibers run rostrocaudally, are focally innervated, and in adult rats, are approximately 3.0 cm in length. (unboundmedicine.com)
  • B) Contraction mechanism. (appbrain.com)
  • The sarcoplasmic reticulum (SR) in heart muscle releases a large amount of Ca 2+ in response to a small amount of trigger Ca 2+ by the mechanism of the Ca 2+ -induced Ca 2+ -release. (springer.com)
  • Understanding the molecular mechanism of muscle contraction started with the discovery that striated muscle is composed of interdigitating filaments which slide against each other. (springer.com)
  • The relative importance of these targets in the intact cell is not known and conflicting theories abound regarding the mechanism(s) whereby NO and ROS regulate contraction. (nih.gov)
  • Dr. Stull and his colleagues discovered that when one of the chemicals in the primary contraction mechanism - a protein called calmodulin - is in short supply, a second series of chemical reactions kicks in to take up the slack. (innovations-report.com)
  • Despite the fundamental role of ECC in skeletal muscle function of all vertebrate species, the molecular mechanism underpinning the communication between the two key proteins involved in the process (DHPR and RyR1) is still largely unknown. (springer.com)
  • Calderón JC, Bolaños P, Caputo C (2014) The excitation-contraction coupling mechanism in skeletal muscle. (springer.com)
  • X‐ray diffraction with intense synchrotron radiation has demonstrated a structural basis for the molecular mechanism underlying muscle contraction with high spatial‐ and time‐resolution. (els.net)
  • The mechanism of action of Argireline peptide targets the pre-synaptic pathway of the muscle contraction process by mimicking the N-terminal end of SNAP-25. (thefreedictionary.com)
  • Sliding Filament Mechanism in Muscle Contraction: Fifty Years of Research covers the history of the sliding filament mechanism in muscle contraction from its discovery in 1954 by H.E. Huxley through and including modern day research. (buecher.de)
  • There is no gradation of force produced by a motor unit by varying the level of motoneuron excitation -gradation of force output of a single motor unit is realized through rate coding -recruitment is the primary mechanism which determine the strength of a voluntary contraction. (biology-online.org)
  • aims to bring together leading academic scientists, researchers and research scholars to exchange and share their experiences and research results on all aspects of Molecular Mechanism of Muscle Contraction. (waset.org)
  • Also, high quality research contributions describing original and unpublished results of conceptual, constructive, empirical, experimental, or theoretical work in all areas of Molecular Mechanism of Muscle Contraction are cordially invited for presentation at the conference. (waset.org)
  • ICMMMC 2021 has teamed up with the Special Journal Issue on Molecular Mechanism of Muscle Contraction . (waset.org)
  • A rise in internal Ca2+ is the signal which activates the contractile mechanism in muscle. (rti.org)
  • The objective of this study was to elucidate the mechanism of transcranial magnetic stimulation (TMS) with maximum voluntary muscle contraction (MVC) (used to facilitate motor neuron function), the effects of magnetic stimulation at the foramen magnum level with MVC were tested by recording motor evoked potentials (MEPs) and the maximum muscle force. (igi-global.com)
  • The mechanism for vertebrate striated muscle contraction. (ahajournals.org)
  • In vertebrate striated muscle (heart and skeletal muscle), actin and myosin are organized with several accessory proteins in highly ordered sets of interdigitating thin and thick filaments, respectively, forming repetitive 2.0-2.5 μ m long sarcomeres [ 2 ]. (hindawi.com)
  • Actin and myosin are much less organized in smooth muscle when compared to skeletal muscle. (wikiversity.org)
  • For the past 60 years, muscle contraction had been thought to be governed exclusively by the contractile filaments, actin, and myosin. (frontiersin.org)
  • Just over a decade ago, we discovered that eccentric contractions were associated with a force that could not be assigned to actin and myosin, but was at least in part associated with the filamentous protein titin. (frontiersin.org)
  • A muscle contraction (also known as a muscle twitch or simply twitch ) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. (wikidoc.org)
  • Muscle contraction occurs when the constitutive proteins, actin and myosin, interact via crossbridge formation, powered by the hydrolysis of adenosine triphosphate (ATP). (els.net)
  • Muscle contraction occurs when constitutive proteins actin and myosin in muscle interact with each other, powered by the hydrolysis of adenosine triphosphate (ATP), leading to a force generation or a shortening of the sarcomere. (els.net)
  • The striated appearance of skeletal muscle tissue is a result of repeating bands of the proteins actin and myosin that are present along the length of myofibrils. (oercommons.org)
  • I'm having a hard time understanding how actin and myosin react during a muscle contraction. (biology-online.org)
  • Unlike skeletal muscle, the contractions of smooth and cardiac muscles are myogenic (meaning that they are initiated by the smooth or heart muscle cells themselves instead of being stimulated by an outside event such as nerve stimulation), although they can be modulated by stimuli from the autonomic nervous system. (wikipedia.org)
  • We also briefly consider actomyosin mutation effects in cardiac and skeletal muscle function and the possibility to treat these defects by drugs. (hindawi.com)
  • Four original research articles in the issue were devoted to heart muscle and cardiac disease. (hindawi.com)
  • tested the effect of the hypertrophic cardiomyopathy-linked mutation in human cardiac troponin I (cTnI) on the contractile properties and myofilament protein phosphorylation in papillary muscle preparations from the left (LV) and right (RV) ventricles of R21C+/+-knock-in mice. (hindawi.com)
  • Cardiac Muscle resembles skeletal muscle in its structure and in regulation of actin-myosin interactions and muscle contraction. (wikiversity.org)
  • Here, we report that TCS impairs ECC of both cardiac and skeletal muscle in vitro and in vivo. (pnas.org)
  • Voltage clamp experiments showed that TCS partially inhibits L-type Ca 2+ currents of cardiac and skeletal muscle, and [ 3 H]PN200 binding to skeletal membranes is noncompetitively inhibited by TCS in the same concentration range that enhances [ 3 H]ryanodine binding. (pnas.org)
  • Skeletal and cardiac muscles are called striated muscle because of their striped appearance under a microscope which is due to the highly organized alternating pattern of A band and I band. (wikidoc.org)
  • Chapters include topics in dynamic X-ray diffraction, electron microscopy, muscle mechanisms, in-vitro motility assay, cardiac versus smooth muscle, motile systems, and much more. (buecher.de)
  • The body contains three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle ( Figure ). (oercommons.org)
  • Cardiac muscle cells are branched and striated, but short. (oercommons.org)
  • Cardiac muscle tissue is only found in the heart, and cardiac contractions pump blood throughout the body and maintain blood pressure. (oercommons.org)
  • Like skeletal muscle, cardiac muscle is striated, but unlike skeletal muscle, cardiac muscle cannot be consciously controlled and is called involuntary muscle. (oercommons.org)
  • Contraction of the heart is a complex process initiated by the electrical excitation of cardiac myocytes (excitation-contraction coupling, ECC). (kegg.jp)
  • Ca2+ is the central factor in myocardial contraction and the potential of a cardiac system to be activated by Ca2+ is characterized by its Ca2+ sensitivity. (fitness-vip.com)
  • Isometric contractions can be distinguished further: There is a difference in experience between intending to hold still against the resistance of something else trying to move you and intending to move but not being able to overcome the resistance to movement. (humankinetics.com)
  • As a result, isometric contractions generate force and tension without any movement through your joints. (healthline.com)
  • Earlier experiments indicates that motor unit activity during isometric contractions can be imaged using a high-definition ultrasound scanner. (bibsys.no)
  • Performance of rat plantar flexor muscles by active stretching during ankle rotations and isometric contractions. (cdc.gov)
  • The performance of rat plantar flexor muscles by repeated stretches (30) using velocity-controlled ankle rotations from 1.57 to 0.70 rad (0.87 rad s-1: slow stretch, 10.47 rad s-1: fast stretch) and repeated isometric contractions (30) at 1.13 rad was examined. (cdc.gov)
  • Half contraction times increased linearly for stretches but were larger than for isometric contractions. (cdc.gov)
  • One hour of rest following the stretches and isometric contractions did not restore muscle performance. (cdc.gov)
  • It is concluded that isometric contractions of skeletal muscle can create a force deficit which is much less than that following stretches. (cdc.gov)
  • In an isotonic contraction, the muscle length can either shorten to produce a concentric contraction or lengthen to produce an eccentric contraction. (wikipedia.org)
  • In concentric contraction, muscle tension is sufficient to overcome the load, and the muscle shortens as it contracts. (wikipedia.org)
  • During a concentric contraction, a muscle is stimulated to contract according to the sliding filament theory. (wikipedia.org)
  • In relation to the elbow, a concentric contraction of the biceps would cause the arm to bend at the elbow as the hand moved from the leg to the shoulder (a biceps curl). (wikipedia.org)
  • A concentric contraction of the triceps would change the angle of the joint in the opposite direction, straightening the arm and moving the hand towards the leg. (wikipedia.org)
  • There is also a difference in experience between maintaining an isometric contraction following a concentric contraction and maintaining an isometric contraction following an eccentric contraction. (humankinetics.com)
  • What is a concentric contraction? (healthline.com)
  • A concentric contraction is a type of muscle activation that causes tension on your muscle as it shortens. (healthline.com)
  • Unlike a concentric contraction, eccentric movements do not pull a joint in the direction of a muscle contraction. (healthline.com)
  • There are a number of subtleties in the measurement of electrically evoked muscle contractions, but the basic result is that the involuntary contractions were enhanced but the voluntary contractions weren't. (runnersworld.com)
  • Movement of the muscles of the heart and other organs is involuntary and controlled by the autonomic nervous system. (thefreedictionary.com)
  • The term "myoclonus" is used to denote a condition in which a portion of a muscle, entire muscle, or group of muscles contracts in a coarse, repetitive, involuntary, and rhythmic manner at rates up to 60 times per minute (sometimes even occurring during sleep). (petmd.com)
  • Involuntary, continuous, coarse, and rhythmic contractions of a muscle, portion of a muscle, or group of muscles is the most common sign to look out for. (petmd.com)
  • Voluntary muscle contractions are initiated in the brain, while the spinal cord initiates involuntary reflexes . (wikidoc.org)
  • Involuntary muscles such as the heart or smooth muscles in the gut and vascular system contract as a result of non-conscious brain activity or stimuli endogenous to the muscle itself. (wikidoc.org)
  • Smooth muscle (involuntary) contractions. (wikidoc.org)
  • The involuntary eyelid muscle contraction usually affects just the lower eyelid. (thefreedictionary.com)
  • Smooth muscle has no striations, is not under voluntary control, has only one nucleus per cell, is tapered at both ends, and is called involuntary muscle. (oercommons.org)
  • This would be the first treatment authorized EU-wide for this rare condition that is characterized by chronic pain, fatigue, and muscle stiffness resulting in frequent falls and disability. (medscape.com)
  • Together, the findings showed that patients with NDM treated with mexiletine experienced significant relief in muscle stiffness. (medscape.com)
  • Mexiletine, which was first authorized in Europe in the 1970s to restore normal heart rhythm, blocks channels for sodium ions in muscle cells, leading to a reduction in muscle contraction rate and stiffness. (medscape.com)
  • Excessive physical exercise causes muscle soreness and stiffness. (scribd.com)
  • These two papers defined the sliding filament model of muscle contraction and were the first to demonstrate that the generation of force and cellular shortening could be explained by a fundamental interaction between two distinct proteins. (biophysics.org)
  • This occurs throughout the length of the muscle, generating a force at the origin and insertion, causing the muscle to shorten and changing the angle of the joint. (wikipedia.org)
  • Specifically, Fenn, who worked in the laboratory of Hill and measured heat and work production in frog muscles, found that a muscle allowed to shorten liberated more energy than a muscle held isometrically or a muscle that was stretched. (frontiersin.org)
  • If enough myofibrils shorten, the whole muscle fiber slides shorter. (humankinetics.com)
  • Whether or not the entire muscle does actually shorten depends on outside factors, specifically how much resistance exists. (humankinetics.com)
  • On contraction, VSMCs shorten, thereby decreasing the diameter of a blood vessel to regulate the blood flow and pressure. (genome.jp)
  • Your muscles are activated, but they are not required to lengthen or shorten. (healthline.com)
  • Concentric muscle contractions involve movements that shorten your muscles. (healthline.com)
  • While under tension, the muscle may lengthen , shorten or remain the same . (wikidoc.org)
  • They attach to the sarcolemma at their ends, so that as myofibrils shorten, the entire muscle cell contracts ( Figure ). (oercommons.org)
  • Muscle contractions can be described based on two variables: length and tension. (wikipedia.org)
  • A muscle contraction is described as isometric if the muscle tension changes but the muscle length remains the same. (wikipedia.org)
  • In contrast, a muscle contraction is isotonic if muscle tension remains the same throughout the contraction. (wikipedia.org)
  • In natural movements that underlie locomotor activity, muscle contractions are multifaceted as they are able to produce changes in length and tension in a time-varying manner. (wikipedia.org)
  • Therefore, neither length nor tension is likely to remain the same in muscles that contract during locomotor activity. (wikipedia.org)
  • In skeletal muscles, muscle tension is at its greatest when the muscle is stretched to an intermediate length as described by the length-tension relationship. (wikipedia.org)
  • Muscle tension is the force exerted by the muscle on an object whereas a load is the force exerted by an object on the muscle. (wikipedia.org)
  • When muscle tension changes without any corresponding changes in muscle length, the muscle contraction is described as isometric. (wikipedia.org)
  • If the muscle length changes while muscle tension remains the same, then the muscle contraction is isotonic. (wikipedia.org)
  • Therefore, neither length nor tension is likely to remain constant when the muscle is active during locomotor activity. (wikipedia.org)
  • An isometric contraction of a muscle generates tension without changing length. (wikipedia.org)
  • In isotonic contraction, the tension in the muscle remains constant despite a change in muscle length. (wikipedia.org)
  • It had various ill-defined names in the past including tension headache, stress headache, muscle contraction headache, psychomyogenic headache, ordinary headache, and psychogenic headache. (medscape.com)
  • Different aspects of the force-generating transition are reflected in the changes in tension development by muscle cells, myofibrils and single molecules upon changes in temperature, altered phosphate concentration, or length perturbations. (hindawi.com)
  • Added resistance also comes from other forces, such as the weight of something being carried, an opposing muscle contraction, or even an emotional state (for example, tension, anger, or the effort not to cry will often create resistance, while relaxation, happiness, or relief will often decrease resistance). (humankinetics.com)
  • When you perform any of these actions, the tension applied to your targeted muscle is consistent and does not exceed the weight of the object you are applying force to. (healthline.com)
  • Elastic elements sustaining the tension that muscle exerts during contraction are thought to be resided somewhere in a sarcomere. (els.net)
  • Twitch and tetanic tension per unit area are about twice as great in the metathoracic muscles as in the faster, mesothoracic ones. (biologists.org)
  • The brain sends signals, in the form of action potentials , through the nervous system to the motor neuron that innervates the muscle fiber. (wikidoc.org)
  • In a new study, UT Southwestern researchers report that one set of chemical reactions resulting in the contraction of the smooth-muscle cells is augmented by a second chemical pathway that kicks in when the first pathway is limited. (innovations-report.com)
  • The first step in the primary chemical pathway for muscle contraction is for calcium in the muscle cell to combine with calmodulin. (innovations-report.com)
  • So the signaling system has recruited a second pathway to enhance the limited activation of MLCK, which leads to a strong muscle contraction. (innovations-report.com)
  • At the end of the primary chemical pathway, an enzyme called phosphatase can remove the phosphate from the myosin, hampering the muscle cell contraction. (innovations-report.com)
  • In this second pathway, the phosphates are no longer taken away from the myosin, which allows more phosphorylated myosin to remain, leading to a stronger muscle contraction," Dr. Stull said. (innovations-report.com)
  • This occurs when a muscle's force of contraction matches the total load on the muscle. (wikipedia.org)
  • This occurs when the force generated by the muscle exceeds the load opposing its contraction. (wikipedia.org)
  • Campiglio M, Kaplan MM, Flucher BE (2018b) STAC3 incorporation into skeletal muscle triads occurs independent of the dihydropyridine receptor. (springer.com)
  • For voluntary muscles, contraction occurs as a result of conscious effort originating in the brain . (wikidoc.org)
  • Moreover, changes in muscle insulin sensitivity occurs independent of changes in protein synthesis ( 15 ), indicating involvement of posttranslational mechanisms. (diabetesjournals.org)
  • It is not self-evident, however, that the mechanical cycle occurs during steady-state isometric contraction where no work is produced. (spiedigitallibrary.org)
  • Smooth muscle tissue occurs in the walls of hollow organs such as the intestines, stomach, and urinary bladder, and around passages such as the respiratory tract and blood vessels. (oercommons.org)
  • When a muscle cramp occurs, you can try to gently stretch out the muscle involved and add warmth to the affected muscle, but to find a more long-term solution, you might need to try to discover just what might be taking place in the affected muscles. (jamaica-star.com)
  • That is, a contraction occurs between the end of economic growth and the end of the subsequent recession . (thefreedictionary.com)
  • The aim of this study is to compare the effectiveness of different verbal instruction on pelvic floor muscle contraction among males. (clinicaltrials.gov)
  • This study will examine pelvic floor muscle contraction following six different verbal instructions among males. (clinicaltrials.gov)
  • But, results are not as sufficient as workouts that combine all three types of muscle contractions. (healthline.com)
  • In this lecture from Aura Wellness Center, Dr. Paul Jerard, E-RYT 500 explains the types of muscle contractions students experience, during asana sessions, regardless of whether they hold a pose or during a vinyasa flow. (yoga-teacher-training.org)
  • The ordered arrangement on different hierarchical levels in muscles is highly beneficial to the effectiveness of the contractile process which is reflected in the independent evolution [ 9 ] of similar sarcomere organizations in phylogenetically distant organisms such as mammalians and Cnidaria (e.g., jellyfish). (hindawi.com)
  • The resting length of the sarcomere is approximately 2.0 μ m in the human heart and 2.5 μ m in human skeletal muscle. (hindawi.com)
  • 7. Sarcomere: Between two Z lines, unit of contraction. (scribd.com)
  • The function of titin, the biggest protein involved in various processes in vertebrate skeletal muscle including sarcomere assembly, passive elasticity, myofibrillogenesis, gene regulation, and signaling in health and disease, is still not fully understood. (hindawi.com)
  • In skeletal muscle, titin spans each half-sarcomere from the Z-band to M-line. (hindawi.com)
  • Prior to the 1950s, muscle contraction and force production were thought to be caused by the folding of long protein chains visible in the middle of the sarcomere. (frontiersin.org)
  • Sliding filament theory is a proposal on the basis of the discovery that when a sarcomere shortens, two types of filaments slide each other with little change in their lengths, resulting in an overall shortening of muscle. (els.net)
  • a) Hirarchical structure of vertebrate skeletal muscle and structure of a sarcomere. (els.net)
  • b) Shortening of the sarcomere in muscle contraction. (els.net)
  • Sarcomere Dynanmics, Stepwise Shortening, and the Nature of Contraction. (buecher.de)
  • After 7 days, they did a series of muscle tests, including maximal voluntary contractions and various electrically stimulated muscle contractions. (runnersworld.com)
  • Audiograms were performed under conditions of rest and maximal contraction of the tensor tympani muscle. (nih.gov)
  • This study aimed to examine the effect of taurine ingestion on maximal voluntary muscle torque and power in trained male athletes with different caffeine habits. (nih.gov)
  • Taurine ingestion is detrimental to maximal voluntary muscle power and both maximal isokinetic and isometric peak torque in noncaffeine consumers, whereas taurine ingestion in caffeine-deprived caffeine consumers improves maximal voluntary muscle power but has no effect on other aspects of contractile performance. (nih.gov)
  • To estimate the behaviour of whole muscle, measures of single fibres, fibre bundles, or small whole muscles during controlled, maximal contractions are often extrapolated to larger sizes by scaling the forces with cross-sectional area and the lengths and velocities with optimal length ( Zajac, 1989 ). (frontiersin.org)
  • Subjects underwent two experimental treatments: 15 s of ischaemic isometric contraction at 66% of maximal force, and 40 min circulatory occlusion. (biomedsearch.com)
  • Stimulation of these receptors activates a cascade of intracellular events that lead to ASMC contraction or relaxation. (omicsonline.org)
  • At 35 C the twitch duration (onset to 50% relaxation) is 5.5-6.5 ms for mesothoracic muscles and 11-13 ms for metathoracic ones. (biologists.org)
  • Smooth muscle is regulated by cytosolic Ca 2+ concentration like in skeletal muscle. (wikiversity.org)
  • The vascular smooth muscle cell (VSMC) is a highly specialized cell whose principal function is contraction. (genome.jp)
  • Researchers at UT Southwestern Medical Center at Dallas are the first to use genetically engineered mice containing a fluorescent molecule to examine in real time the chemical reactions that result in smooth-muscle contraction. (innovations-report.com)
  • Smooth muscle, found in the walls of blood vessels and in internal organs such as lungs, stomach and the bladder, contracts as the end result of a series of chemical reactions. (innovations-report.com)
  • The result is that the strength of the contraction of smooth-muscle cells remains robust. (innovations-report.com)
  • Myosin needs the phosphate - in a process called phosphorylation - to initiate contraction in smooth-muscle cells. (innovations-report.com)
  • When the researchers treated smooth muscle cells from mice with the drug carbachol, the amount of calcium available within the cells increased. (innovations-report.com)
  • To track the progress of this intricate chemical dance, researchers genetically engineered a mouse containing a fluorescent molecule, or biosensor that directly monitors the calcium/calmodulin activation of MLCK in real time in smooth-muscle cells. (innovations-report.com)
  • Here, we determined that IQGAP1 modulates airway smooth muscle contractility. (jci.org)
  • RhoA, a regulator of airway smooth muscle contractility, was activated in airway smooth muscle lysates from Iqgap1 -/- mice. (jci.org)
  • Likewise, knockdown of IQGAP1 in primary human airway smooth muscle cells increased RhoA activity. (jci.org)
  • Together, these data demonstrate that IQGAP1 acts as a scaffold that colocalizes p190A-RhoGAP and RhoA, inactivating RhoA and suppressing airway smooth muscle contraction. (jci.org)
  • A ) Co-immunoprecipitation of IQGAP1 and p190A-RhoGAP in lysates of human airway smooth muscle. (jci.org)
  • B ) Co-immunoprecipitation of IQGAP1 and FLAG in lysates of human airway smooth muscle transfected with Rho-FLAG or GFP control. (jci.org)
  • C ) Association of IQGAP1 with both RhoA and p190A-RhoGAP was also demonstrated by PLA in cultured human airway smooth muscle cells. (jci.org)
  • D ) Spatial association of p190A-RhoGAP and RhoA, tested by PLA in cultured human airway smooth muscle cells with and without IQGAP1 knockdown and seeded at equal density. (jci.org)
  • Smooth muscle was stained with anti-α-SMA antibody (red). (jci.org)
  • Number of PLA foci per unit area of smooth muscle is also shown ( n = 4 per group). (jci.org)
  • 2+] channel on muscle contraction , we hypothesized that magnolol affect the colonic smooth muscle contraction mediated through the L-type calcium channels. (thefreedictionary.com)
  • The active effector of airway reactivity is airway smooth muscle, located in the wall of the airways, which contraction induces a reduction in airway lumen and hence an increased resistance to air flow. (omicsonline.org)
  • The contractile state of airway smooth muscle (ASM) is modulated by a variety of extracellular agonists acting on specific receptors located in the plasma membrane of ASM cells (ASMCs). (omicsonline.org)
  • Smooth muscle cells are short, tapered at each end, and have only one plump nucleus in each. (oercommons.org)
  • An anti-oestrogenic effect of progesterone has therefore been demonstrated in rat detrusor smooth muscle. (bl.uk)
  • In smooth muscle the sarcoplasmic reticulum system is much less extensive3,4 and normal contractile activity is very sensitive to calcium levels in the bathing medium5?7. (rti.org)
  • These findings, together with the small size of smooth muscle cells which minimises diffusion time from the plasma membrane to the contractile apparatus, have suggested to some investigators that the Ca2+ which enters the cell during Ca2+-mediated action potentials is either sufficient by itself to activate contraction or is a necessary trigger for the further release of Ca2+ from internal stores8?11. (rti.org)
  • This notion is given support by the observation that contractile activity rapidly dies out when smooth muscle preparations are exposed to calcium-free solutions. (rti.org)
  • We report here on spontaneous contractile and electrical activity, and evoked mechanical activity, recorded after prolonged exposure to calcium-free EGTA saline in intestinal smooth muscle of cat. (rti.org)
  • Using optical imaging, researchers from Yale University found that capillary pericytes in mice and humans do not express smooth muscle actin and are morphologically and functionally distinct from adjacent precapillary smooth muscle cells (SMCs). (scitechdaily.com)
  • In the accompanying movie of a mouse brain taken by specialized microscope, researchers at the Yale School of Medicine found that smooth muscle (in cyan) actually constricts during a stroke instead of expanding, as would be expected to minimize damage during a stroke. (scitechdaily.com)
  • Any process that modulates the frequency, rate or extent of smooth muscle contraction. (broadinstitute.org)
  • We have analyzed the behavior of a linear, cyclic, four state model of regulation of contraction of smooth muscle. (illinois.edu)
  • We conclude that, although the model fits the data well, because of its energetic failure, it must be considered with strong reservations as a possible good representation of real smooth muscle. (illinois.edu)
  • Endothelial cells protrude through holes in the internal elastic lamina in arterioles to make contact with vascular smooth muscle cells. (sciencemag.org)
  • Gap junctions are present at these sites where endothelial cells meet vascular smooth muscle cells. (sciencemag.org)
  • showed that it was Ca 2+ , rather than IP 3 , that entered vascular smooth muscle cells through voltage-gated Ca 2+ channels, subsequently passed through gap junctions into endothelial cells, and initiated vasodilation mediated by endothelial cells. (sciencemag.org)
  • These results resolve a long-standing controversy over how vascular smooth muscle cells communicate with endothelial cells to trigger feedback vasodilation. (sciencemag.org)
  • Vascular smooth muscle contraction is suppressed by feedback dilation mediated by the endothelium. (sciencemag.org)
  • In skeletal muscle arterioles, this feedback can be activated by Ca 2+ signals passing from smooth muscle through gap junctions to endothelial cells, which protrude through holes in the internal elastic lamina to make contact with vascular smooth muscle cells. (sciencemag.org)
  • We provide evidence that Ca 2+ entry through L-type voltage-dependent Ca 2+ channels (VDCCs) in vascular smooth muscle can pass to the endothelium through positions aligned with holes in the internal elastic lamina in amounts sufficient to activate endothelial cell Ca 2+ signaling. (sciencemag.org)
  • In endothelial cells in which IP 3 receptors (IP 3 Rs) were blocked, VDCC-driven Ca 2+ events were transient and localized to the endothelium that protrudes through the internal elastic lamina to contact vascular smooth muscle cells. (sciencemag.org)
  • Thus, agonists that stimulate vascular smooth muscle depolarization provide Ca 2+ to endothelial cells to activate a feedback circuit that protects tissue blood flow. (sciencemag.org)
  • This fundamental response depends on myogenic tone, an ongoing pressure-induced vascular smooth muscle cell contraction in small arteries that can be rapidly modulated by perivascular nerves, autacoids, the extracellular accumulation of metabolites, and the endothelium ( 1 , 2 ). (sciencemag.org)
  • Myogenic tone is underpinned by increases in intraluminal pressure depolarizing vascular smooth muscle and increasing the open probability of L-type voltage-dependent Ca 2+ channels (VDCCs) ( 3 , 4 ). (sciencemag.org)
  • This thinking explained most observations for concentric and isometric, but not for eccentric muscle contractions. (frontiersin.org)
  • Exercise involving eccentric muscle contractions is well known to impair force production capacities (Janecki et al. (thefreedictionary.com)
  • Eccentric muscle contractions are the braking forces your muscles employ during downhill running. (thefreedictionary.com)
  • Eccentric muscle contractions were separated by 10 s periods to minimize metabolic inhibition which is often associated with accumulation of inorganic phosphate in muscle fibres (Allen et al. (thefreedictionary.com)
  • DHPR transmits the contractile signal to another Ca 2+ channel, ryanodine receptor (RyR1), embedded in the membrane of the sarcoplasmic reticulum (SR), which releases a large amount of Ca 2+ ions from the SR that initiate muscle contraction. (springer.com)
  • Block BA, Imagawa T, Campbell KP, Franzini-Armstrong C (1988) Structural evidence for direct interaction between the molecular components of the transverse tubule/sarcoplasmic reticulum junction in skeletal muscle. (springer.com)
  • In striated muscle there is a well developed sarcoplasmic reticulum which stores and releases the bulk of the Ca2+ involved in the contraction cycle1,2, allowing the muscle to operate relatively independently of external calcium levels. (rti.org)
  • This gives it enough 'voltage' to reach its threshold which initiates an action potential on the muscle cell membrane (sarcolemma) which stimulates Ca2+ release from the sarcoplasmic reticulum to stimulate contraction (second messenger). (biology-online.org)
  • Utilizing myosin II motor proteins to initiate contraction events in actin networks, active muscle gels have the unique potential of acting as microscopic actuators. (mit.edu)
  • Ca2+ enters the myoplasm through the Ca channels, it may trigger release of new Ca2+ from the SR or it may be stored in the SR. The intracellular Ca2+ can initiate contraction through the TN system. (fitness-vip.com)
  • Despite intense studies, several molecular events in the contraction process are poorly understood, including the relationship between force-generation and phosphate-release in the ATP-turnover. (hindawi.com)
  • However, on May 22, 1954 two classic papers by Andrew Huxley and Rolf Niedergerke and Hugh Huxley (no relation to Andrew) and Jean Hanson were published in the journal Nature that described the molecular basis of muscle contraction. (biophysics.org)
  • Our knowledge of this exquisitely structured molecular machine has exploded in the last four decades, thanks to a bewildering array of techniques for studying intact muscle, muscle fibres, myofibrils and single myosin molecules. (springer.com)
  • During the last decades we have seen a major revision of the immutable postulates underlying the molecular mechanisms of muscle contraction. (hindawi.com)
  • Molecular Synchronization in Actomyosin Motors from Single Molecule to Muscle Fiber via Nanomuscle. (buecher.de)
  • Energetics, Mechanics, and Molecular Engineering of Calcium Cycling in Skeletal Muscle. (buecher.de)
  • Thoroughly researched using experimentation and re-examination of all previously published evidence, Molecular and Physiological Mechanisms of Muscle Contraction is a carefully crafted treatise and revision of previous conceptions of muscle contraction. (bokklubben.no)
  • Huxley and Niedergerke studied intact frog muscle cells, which unfortunately are too thick to reliably measure specific features by conventional light or phase contrast microscopy. (biophysics.org)
  • Huxley and Hanson obtained their results using light-microscopy and isolated myofibrils, which are extremely thin relative to whole muscle cells and, thus, are better suited for conventional imaging. (biophysics.org)
  • Huxley and Hanson additionally extracted myosin from the A-bands, leaving arrays of actin filaments, and demonstrated the role of adenosine triphosphate (ATP) hydrolysis, which provides energy to drive biological processes, in powering contraction. (biophysics.org)
  • In the early 1950s, careful analysis of A-band dimensions revealed that myosin filaments were not substantially shortening under a variety of contractile conditions, and thus, could not account for muscle contraction, force production and the large length changes that muscle tissue can undergo ( Huxley, 1953 ). (frontiersin.org)
  • In 1957, Andrew Huxley proposed how this relative sliding might occur, and provided a mathematical framework for what is now known as the cross-bridge theory of muscle contraction ( Huxley, 1957 ). (frontiersin.org)
  • The mechanical outcomes (muscle force, stiffness and deformation) are determined from the same voluntary command of the PNS, and is based on the Huxley sliding filaments model upscale at the MU scale using the distribution-moment theory proposed by Zahalak. (archives-ouvertes.fr)
  • The new model this book proposes is not a replacement for the standard Huxley model of muscle contraction, but a modification based on recent research and synthesized with pre-existing data and conceptions. (bokklubben.no)
  • The mechanisms of contraction in these muscle tissues are similar to those in skeletal muscle tissues. (wikipedia.org)
  • This interprets the effects of beat frequency and external [Ca 2+ ] on twitch contractions in intact heart muscle. (springer.com)
  • Force Summation describes the addition of individual twitch contractions to increase the intensity of overall muscle contraction. (wikidoc.org)
  • We here review these issues in relation to controversies regarding basic physiological properties of striated muscle. (hindawi.com)
  • Muscle cells use an extensively organized but still poorly understood actin-myosin contractile apparatus to generate force and movement and respond to various physiological stimuli. (hindawi.com)
  • TCS is capable of altering the activity of type 1 ryanodine receptor (RyR1), but its potential to influence physiological excitation-contraction coupling (ECC) and muscle function has not been investigated. (pnas.org)
  • Excitation-contraction coupling (ECC) is a physiological process that links excitation of muscles by the nervous system to their mechanical contraction. (springer.com)
  • These models suffer from several important limitations such lacks of physiological realism, personalization, and representability when a complete muscle is considered. (archives-ouvertes.fr)
  • Analysis and Characteristics of Some Major Biophysical, Enzymological and Physiological Phenomena in an Intact Unit Cell During Contraction (Isometric and Isotonic). (bokklubben.no)
  • We found that prior in situ contraction of m. extensor digitorum longus (EDL) and treadmill exercise increased muscle and whole-body insulin sensitivity in wild-type (WT) mice, respectively. (diabetesjournals.org)
  • Prior in situ contraction did not increase insulin sensitivity in m. soleus from either genotype. (diabetesjournals.org)
  • However, in WT EDL muscle, prior in situ contraction enhanced insulin-stimulated phosphorylation of TBC1D4 Thr 649 and Ser 711 . (diabetesjournals.org)
  • These comparable results for the simulated and in situ muscle also show that this modelling framework behaves in ways that are consistent with experimental muscle. (frontiersin.org)
  • These findings show that our C2C12 cell contraction system reproduces the muscle phenotypes that arise in vivo (exercise), in situ (hindlimb muscles in an anesthetized animal), and in vitro (dissected muscle tissues in incubation buffer) by acute muscle contraction, demonstrating that the system is applicable for the analysis of intracellular events evoked by acute muscle contraction. (harvard.edu)
  • The velocity of ankle rotations producing stretches of rat plantar flexor muscles working in situ is not a factor in reducing muscle performance. (cdc.gov)
  • A concept known as the size principle allows for a gradation of muscle force during weak contraction to occur in small steps, which then become progressively larger when greater amounts of force are required. (wikidoc.org)
  • Two challenges currently faced by active muscle gels are their slow contraction time and weak contraction forces. (mit.edu)
  • Examples: Postural muscles of neck, back. (scribd.com)
  • This resting tone keeps the muscles ready to respond and in postural muscles automatically adjusts for slight shifts in weight and balance when we sit, stand, and walk. (humankinetics.com)
  • Oestrogens have been shown to have an inhibitory effect on detrusor muscle contraction after in vitro and in vivo treatment. (bl.uk)
  • Before the 1950s, it was widely accepted that force production and muscle contraction resulted from a shortening of myosin filaments. (biophysics.org)
  • To account for their observations, both groups surmised that muscle contraction was not caused by A-band (i.e. myosin filament) shortening, but rather by the sliding of actin relative to myosin filaments, whose lengths remained constant. (biophysics.org)
  • In technical terms, there are two types of contraction: concentric, also called shortening contraction, and eccentric, in which the length actually increases during contraction. (thestudentroom.co.uk)
  • Therefore, we propose that muscle contraction involves three filaments, actin, myosin and titin, and that titin regulates force by binding calcium and by shortening its spring length by binding to actin. (frontiersin.org)
  • This shortening had been thought to be caused by lactic acid, but this theory was refuted by experiments demonstrating that contractions could be obtained in the absence of lactic acid in muscles poisoned with iodoacetic acid ( Lundsgaard, 1930 ). (frontiersin.org)
  • Shortening of a myofibril during contraction is prevented by light cross-linking with 1-ethyl-3-[3-dimethylamino)-propyl]-carbodiimide. (spiedigitallibrary.org)
  • Coordination is skill specific) -facilitation of contraction through various mechanisms , which I wont break down here but you should think at stretch shortening cycle -drive to motoneurons from the motor cortex -various spinal cord connection plasticity, though to influence bilateral facilitation / bilateral deficit. (biology-online.org)
  • 4. Despite the differences in isometric contraction kinetics, the maximum shortening velocity (V max ) is similar in mesothoracic and metathoracic wing muscles. (biologists.org)
  • Hard to know, but it bolsters the idea that muscle contractile properties play a role. (runnersworld.com)
  • Muscle contraction results from cyclic interactions between the contractile proteins myosin and actin, driven by the turnover of adenosine triphosphate (ATP). (hindawi.com)
  • Myofibrils are elongated substructures of muscle cells that are comprised of a repeating array of individual contractile units known as sarcomeres. (biophysics.org)
  • As the skeletal muscle cell is an efficient force transducer, it has been incorporated in bio-microdevices using electrical field stimulation for generating contractile patterns. (nih.gov)
  • 1. Muscle fiber: Contractile cells. (scribd.com)
  • Nitric oxide (NO) derivatives and reactive oxygen species (ROS) modulate contractile function of respiratory and limb skeletal muscle. (nih.gov)
  • While nerve impulse profiles are, for the most part, always the same, skeletal muscles are able to produce varying levels of contractile force. (wikidoc.org)
  • The central question is how force generation and movement in muscle contraction are associated with major conformational changes in contractile and regulatory proteins. (els.net)
  • Muscle contractile performances were compared between the first sets as well as between the sets where these variables scored best. (nih.gov)
  • Actin is a globular contractile protein that interacts with myosin for muscle contraction. (oercommons.org)
  • Treatment for 8 days had no effect on isolated detrasor contraction but a single dose reduced detrasor contractile response. (bl.uk)
  • The effect of low concentrations of caffeine on the contractile response of isolated human and rat detrusor muscle was therefore determined. (bl.uk)
  • Isolytic contraction is when a muscle contracts while external forces cause it to lengthen. (wikipedia.org)
  • It is important to understand that a muscle can lengthen and be active (an eccentric contraction), can lengthen and be inactive (a relaxed muscle), or can lengthen and gradually change from active to inactive or vice versa. (humankinetics.com)
  • LENGTHEN every muscle through it's full range of motion on every respective movement. (exercisegoals.com)
  • In the past, various mechanisms including vascular, muscular (ie, constant overcontraction of scalp muscles), and psychogenic factors were suggested. (medscape.com)
  • From this interaction, muscular force is generated from the muscle activation commanded by the Central Nervous System (CNS) that pilots joint motion. (archives-ouvertes.fr)
  • 1 How strongly this percentage carries to strength training individuals is unclear, but there's no doubt about the negative impact that dehydration has on performance in weightlifting, as well as on muscular growth and recovery. (bodybuilding.com)
  • The more likely cause of these headaches is believed now to be abnormal neuronal sensitivity and pain facilitation, not abnormal muscle contraction. (medscape.com)
  • These abnormal contractions occur due to nervous dysfunction and most commonly affect groups of muscles involved in chewing and/or any of the skeletal muscles of the limbs. (petmd.com)
  • Muscle Contraction and Cell Motility 1st Edition by Haruo Sugi and Publisher Pan Stanford Publishing. (vitalsource.com)
  • An adenosine triphosphate molecule stores energy that is released and used by energy-consuming reactions, such as muscle contraction, transmission of nerve. (reference.com)
  • To investigate the potential impact of topiramate on muscle contraction , phrenic nerve-hemidiaphragm preparations were used as an NMJ model and the effects of topiramate and phenytoin (as a control) on the muscle twitch response to electrical stimulation were comparatively evaluated. (thefreedictionary.com)
  • Does a muscle contract stronger when the frequency of the nerve impulses is higher? (biology-online.org)
  • This message, called a nerve impulse or action potential, is carried along motoneurons to the muscle. (fitclick.com)
  • During muscle contraction, globular myosin motor domains (heads) extend from the thick filaments to interact cyclically with actin binding sites on the thin filaments forming so-called cross-bridges (Figure 1(b) ). (hindawi.com)
  • Why, then, was there no effect on voluntary muscle contractions? (runnersworld.com)
  • Because it can be controlled by thought, skeletal muscle is also called voluntary muscle. (oercommons.org)
  • Development of Neurorehabilitation Techniques Using Transcranial Magnetic Stimulation with Voluntary Muscle Contraction. (igi-global.com)
  • Though effective, this type of contraction alone will not produce strength or mass results compared to workouts that combine different muscle contractions. (healthline.com)
  • Combining eccentric and concentric muscle contractions produces greater results in strength training, as it increases muscle strength and mass. (healthline.com)
  • Essential to increasing muscle mass, concentric movements help to increase strength. (healthline.com)
  • gym workouts) can increase voluntary strength when maximum effort is used du ring each muscle contraction , although few studies have demonstrated similar benefits in lower-extremity (legs) muscles in individuals with incomplete SCI. (thefreedictionary.com)
  • I would like to know how the strength of a contraction of a muscle is controlled in detail. (biology-online.org)
  • Phosphorylation of protein kinase B/Akt (Akt), 5′ AMP-activated protein kinase (AMPK), p38 mitogen-activated protein kinase (p38), and c-Jun NH2-terminal kinase (JNK)1/2, which are intracellular signaling proteins typically activated in exercised/contracted skeletal muscle, was observed in the electrically stimulated C2C12 myotubes. (harvard.edu)
  • When both muscle pairs contract together, one contracts concentrically, and the other eccentrically. (thestudentroom.co.uk)
  • When a muscle cell contracts, the molecules create and release bonds between the thick and thin filaments, which ratchet along each other and create a sliding movement that increases their overlap and draws the two ends of the myofibril toward each other. (humankinetics.com)
  • I can feel the electrical pulse then the muscle contracts. (asap.org)
  • This lesson will give an overview of how a specific muscle contracts to allow movement in the body. (sophia.org)
  • When an opposing muscle on the opposite side of a joint contracts to create an opposing movement to its muscle counterpart (example flexion vs. extension). (sophia.org)
  • This means when one muscle contracts, the other relaxes. (sophia.org)
  • Studying cross-bridge dynamics during isometric steady-state contraction requires an equilibrium time-resolved method (not involving application of a transient). (spiedigitallibrary.org)
  • Furthermore, our results suggest that IQGAP1 has the potential to modulate airway contraction severity in acute asthma. (jci.org)
  • Earlier studies have demonstrated that muscle insulin sensitivity to stimulate glucose uptake is enhanced several hours after an acute bout of exercise. (diabetesjournals.org)
  • A cultured C2C12 myotube contraction system was examined for application as a model for acute contraction-induced phenotypes of skeletal muscle. (harvard.edu)
  • These are connected in series to each other forming ~1 μ m wide myofibrils (Figures 1(a) and 1(b) ) that run the entire length of the muscle cell (muscle fiber) and in parallel over the muscle fiber cross-section. (hindawi.com)
  • Within each muscle fiber are myofibrils -long cylindrical structures that lie parallel to the muscle fiber. (oercommons.org)
  • Myofibrils run the entire length of the muscle fiber, and because they are only approximately 1.2 µm in diameter, hundreds to thousands can be found inside one muscle fiber. (oercommons.org)
  • Contraction models can be extended to all levels of calcium-activation by embedding them in a cooperative theory of thin-filament regulation, and a method for achieving this grand synthesis is proposed. (springer.com)
  • The structural alterations in vertebrate skeletal muscles undergoing contraction by synchrotron X‐ray diffraction are outlined by putting a lot of weight on the thin filament as the locus of actomyosin interaction. (els.net)
  • Unlike in skeletal muscle, it is initiated by the phosphorylation of one of the two myosin light chains. (wikiversity.org)
  • Thus the model interpreted some important features in the regulation of the heart muscle contraction. (springer.com)
  • The goal of this work is to review the recent progress in our understanding of ECC in skeletal muscle from the point of view of the structure and interactions of proteins involved in the process, and to highlight the unanswered questions in the field. (springer.com)
  • Bannister RA, Grabner M, Beam KG (2008) The α 1S III-IV loop influences 1,4-dihydropyridine receptor gating but is not directly involved in excitation-contraction coupling interactions with the type 1 ryanodine receptor. (springer.com)
  • Cyclic interactions of myosin and actin are responsible for contraction of muscle. (spiedigitallibrary.org)
  • Evaluating and quantifying the interactions arising during the muscle activation are hard and complex to investigate in experimental conditions. (archives-ouvertes.fr)
  • Peripheral fatigue is caused by the exhaustion of energy reserves and the accumulation of metabolic products in the active muscle.MUSCLE FATIGUE Muscle fatigue may be peripheral or central. (scribd.com)
  • Central fatigue is characterized by work-related pain in the involved muscles and joints that prevents the continuation of physical exercise or decreased the individual's motivation to continue the exercise. (scribd.com)
  • This review article provides a personal perspective on the processes regulated by NO and ROS by addressing three major topics: 1) the regulatory mechanisms by which endogenous NO depresses force production, 2) the processes whereby endogenous ROS modulate contraction of unfatigued muscle, and 3) the site(s) of action and reversibility of ROS effects in muscle fatigue. (nih.gov)
  • n Muscle fatigue. (jamaica-star.com)
  • Rest periods (3 min) between contractions (1900 ms) eliminated effects of fatigue. (cdc.gov)