Recording of change in the size of a part as modified by the circulation in it.
Recording changes in electrical impedance between electrodes placed on opposite sides of a part of the body, as a measure of volume changes in the path of the current. (Stedman, 25th ed)
The resistance to the flow of either alternating or direct electrical current.
Measurement of the volume of gas in the lungs, including that which is trapped in poorly communicating air spaces. It is of particular use in chronic obstructive pulmonary disease and emphysema. (Segen, Dictionary of Modern Medicine, 1992)
A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. It is used principally to calculate stroke volume and cardiac volume, but it is also related to myocardial contractility, thoracic fluid content, and circulation to the extremities.
Part of the arm in humans and primates extending from the ELBOW to the WRIST.
The flow of BLOOD through or around an organ or region of the body.
A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.
Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.
The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.
The upper part of the trunk between the NECK and the ABDOMEN. It contains the chief organs of the circulatory and respiratory systems. (From Stedman, 25th ed)
The inferior part of the lower extremity between the KNEE and the ANKLE.
The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.
Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.
A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
A competitive inhibitor of nitric oxide synthetase.
The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).
The vessels carrying blood away from the capillary beds.
The relative amounts of various components in the body, such as percentage of body fat.
The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.
Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Fluids composed mainly of water found within the body.
Drugs used to cause dilation of the blood vessels.
The volume of air contained in the lungs at the end of a maximal inspiration. It is the equivalent to each of the following sums: VITAL CAPACITY plus RESIDUAL VOLUME; INSPIRATORY CAPACITY plus FUNCTIONAL RESIDUAL CAPACITY; TIDAL VOLUME plus INSPIRATORY RESERVE VOLUME plus functional residual capacity; or tidal volume plus inspiratory reserve volume plus EXPIRATORY RESERVE VOLUME plus residual volume.
The presence of an increased amount of blood in a body part or an organ leading to congestion or engorgement of blood vessels. Hyperemia can be due to increase of blood flow into the area (active or arterial), or due to obstruction of outflow of blood from the area (passive or venous).
A quaternary ammonium parasympathomimetic agent with the muscarinic actions of ACETYLCHOLINE. It is hydrolyzed by ACETYLCHOLINESTERASE at a considerably slower rate than ACETYLCHOLINE and is more resistant to hydrolysis by nonspecific CHOLINESTERASES so that its actions are more prolonged. It is used as a parasympathomimetic bronchoconstrictor agent and as a diagnostic aid for bronchial asthma. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1116)
The volume of air remaining in the LUNGS at the end of a normal, quiet expiration. It is the sum of the RESIDUAL VOLUME and the EXPIRATORY RESERVE VOLUME. Common abbreviation is FRC.
The outer margins of the thorax containing SKIN, deep FASCIA; THORACIC VERTEBRAE; RIBS; STERNUM; and MUSCLES.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
Imaging methods that result in sharp images of objects located on a chosen plane and blurred images located above or below the plane.
Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.
Objective tests of middle ear function based on the difficulty (impedance) or ease (admittance) of sound flow through the middle ear. These include static impedance and dynamic impedance (i.e., tympanometry and impedance tests in conjunction with intra-aural muscle reflex elicitation). This term is used also for various components of impedance and admittance (e.g., compliance, conductance, reactance, resistance, susceptance).
The blood pressure in the VEINS. It is usually measured to assess the filling PRESSURE to the HEART VENTRICLE.
The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.
Regional infusion of drugs via an arterial catheter. Often a pump is used to impel the drug through the catheter. Used in therapy of cancer, upper gastrointestinal hemorrhage, infection, and peripheral vascular disease.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
The measurement of frequency or oscillation changes.
The measure of a BLOOD VESSEL's ability to increase the volume of BLOOD it holds without a large increase in BLOOD PRESSURE. The vascular capacitance is equal to the change in volume divided by the change in pressure.
An occupational disorder resulting from prolonged exposure to vibration, affecting the fingers, hands, and forearms. It occurs in workers who regularly use vibrating tools such as jackhammers, power chain saws, riveters, etc. Symptoms include episodic finger blanching, NUMBNESS, tingling, and loss of nerve sensitivity.
Impaired venous blood flow or venous return (venous stasis), usually caused by inadequate venous valves. Venous insufficiency often occurs in the legs, and is associated with EDEMA and sometimes with VENOUS STASIS ULCERS at the ankle.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
A condition characterized by a chronically swollen limb, often a leg with stasis dermatitis and ulcerations. This syndrome can appear soon after phlebitis or years later. Postphlebitic syndrome is the result of damaged or incompetent venous valves in the limbs. Distended, tortuous VARICOSE VEINS are usually present. Leg pain may occur after long period of standing.
Inflammation of a vein associated with a blood clot (THROMBUS).
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.
Translocation of body fluids from one compartment to another, such as from the vascular to the interstitial compartments. Fluid shifts are associated with profound changes in vascular permeability and WATER-ELECTROLYTE IMBALANCE. The shift can also be from the lower body to the upper body as in conditions of weightlessness.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
Agents causing the narrowing of the lumen of a bronchus or bronchiole.
Any hindrance to the passage of air into and out of the lungs.
Methods of creating machines and devices.
Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.
The position or attitude of the body.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
Distensibility measure of a chamber such as the lungs (LUNG COMPLIANCE) or bladder. Compliance is expressed as a change in volume per unit change in pressure.
Radiographic visualization or recording of a vein after the injection of contrast medium.
The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.
The technique that deals with the measurement of the size, weight, and proportions of the human or other primate body.
Classical loci in ACUPUNCTURE. They are main and collateral channels, regarded as a network of passages, through which vital energy (Qi) circulates and along which acupoints (ACUPUNCTURE POINTS) are distributed. The meridians are a series of 14 lines upon which more than 400 acupoints are located on the body. (The Pinyin Chinese-English Dictionary, p. 359; Dr. Wu Lancheng, Academy of Traditional Chinese Medicine, Beijing)
Measurement of volume of air inhaled or exhaled by the lung.
The continuation of the axillary artery; it branches into the radial and ulnar arteries.
The capability of the LUNGS to distend under pressure as measured by pulmonary volume change per unit pressure change. While not a complete description of the pressure-volume properties of the lung, it is nevertheless useful in practice as a measure of the comparative stiffness of the lung. (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p562)
The posture of an individual lying face up.
Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.
A transient absence of spontaneous respiration.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
Helium. A noble gas with the atomic symbol He, atomic number 2, and atomic weight 4.003. It is a colorless, odorless, tasteless gas that is not combustible and does not support combustion. It was first detected in the sun and is now obtained from natural gas. Medically it is used as a diluent for other gases, being especially useful with oxygen in the treatment of certain cases of respiratory obstruction, and as a vehicle for general anesthetics. (Dorland, 27th ed)
The act of BREATHING in.
The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
External decompression applied to the lower body. It is used to study orthostatic intolerance and the effects of gravitation and acceleration, to produce simulated hemorrhage in physiologic research, to assess cardiovascular function, and to reduce abdominal stress during childbirth.
Elements of limited time intervals, contributing to particular results or situations.
The vessels carrying blood away from the heart.
Methods for assessing flow through a system by injection of a known quantity of an indicator, such as a dye, radionuclide, or chilled liquid, into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)
The mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.
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)
The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein.
The volume of air remaining in the LUNGS at the end of a maximal expiration. Common abbreviation is RV.
Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).
The ability of a substrate to allow the passage of ELECTRONS.
The superior part of the upper extremity between the SHOULDER and the ELBOW.
The number of times an organism breathes with the lungs (RESPIRATION) per unit time, usually per minute.
A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.
Narrowing of the caliber of the BRONCHI, physiologically or as a result of pharmacological intervention.
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.
A standard and widely accepted diagnostic test used to identify patients who have a vasodepressive and/or cardioinhibitory response as a cause of syncope. (From Braunwald, Heart Disease, 7th ed)
These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.
Double-layered inflatable suits which, when inflated, exert pressure on the lower part of the wearer's body. The suits are used to improve or stabilize the circulatory state, i.e., to prevent hypotension, control hemorrhage, and regulate blood pressure. The suits are also used by pilots under positive acceleration.
Analysis of the HYDROGEN ION CONCENTRATION in the lumen of the ESOPHAGUS. It is used to record the pattern, frequency, and duration of GASTROESOPHAGEAL REFLUX.
The vein accompanying the femoral artery in the same sheath; it is a continuation of the popliteal vein and becomes the external iliac vein.
The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.
The neural systems which act on VASCULAR SMOOTH MUSCLE to control blood vessel diameter. The major neural control is through the sympathetic nervous system.
A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.
An idiopathic vascular disorder characterized by bilateral Raynaud phenomenon, the abrupt onset of digital paleness or CYANOSIS in response to cold exposure or stress.
Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity.
Measurement of the pressure or tension of liquids or gases with a manometer.
Drugs used to cause constriction of the blood vessels.
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.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The TEMPERATURE at the outer surface of the body.
Relatively complete absence of oxygen in one or more tissues.
That portion of the body that lies between the THORAX and the PELVIS.
A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.
Enlarged and tortuous VEINS.
Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.
The rate of airflow measured during a FORCED VITAL CAPACITY determination.
Four or five slender jointed digits in humans and primates, attached to each HAND.
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
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.
The blood pressure in the central large VEINS of the body. It is distinguished from peripheral venous pressure which occurs in an extremity.
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.
Skin breakdown or ulceration caused by VARICOSE VEINS in which there is too much hydrostatic pressure in the superficial venous system of the leg. Venous hypertension leads to increased pressure in the capillary bed, transudation of fluid and proteins into the interstitial space, altering blood flow and supply of nutrients to the skin and subcutaneous tissues, and eventual ulceration.
Determination of the quantity of a material present in a mixture by measurement of its effect on the electrical conductivity of the mixture. (Webster, 3d ed)
The farthest or outermost projections of the body, such as the HAND and FOOT.
Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.
Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.
The research and development of ELECTRICAL EQUIPMENT AND SUPPLIES for such medical applications as diagnosis, therapy, research, anesthesia control, cardiac control, and surgery. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The volume of air that is exhaled by a maximal expiration following a maximal inspiration.
Tests involving inhalation of allergens (nebulized or in dust form), nebulized pharmacologically active solutions (e.g., histamine, methacholine), or control solutions, followed by assessment of respiratory function. These tests are used in the diagnosis of asthma.
The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.
Agents that cause an increase in the expansion of a bronchus or bronchial tubes.
Delivery of drugs into an artery.
Application of computer programs designed to assist the physician in solving a diagnostic problem.
Plethysmographic determination in which the intensity of light reflected from the skin surface and the red cells below is measured to determine the blood volume of the respective area. There are two types, transmission and reflectance.
Any of a variety of procedures which use biomolecular probes to measure the presence or concentration of biological molecules, biological structures, microorganisms, etc., by translating a biochemical interaction at the probe surface into a quantifiable physical signal.
Any device or element which converts an input signal into an output signal of a different form. Examples include the microphone, phonographic pickup, loudspeaker, barometer, photoelectric cell, automobile horn, doorbell, and underwater sound transducer. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
The measurement of the density of a material by measuring the amount of light or radiation passing through (or absorbed by) the material.
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.
The process of converting analog data such as continually measured voltage to discrete, digital form.
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.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
An abnormally low volume of blood circulating through the body. It may result in hypovolemic shock (see SHOCK).
Rhythmic, intermittent propagation of a fluid through a BLOOD VESSEL or piping system, in contrast to constant, smooth propagation, which produces laminar flow.
A noninvasive method for assessing BODY COMPOSITION. It is based on the differential absorption of X-RAYS (or GAMMA RAYS) by different tissues such as bone, fat and other soft tissues. The source of (X-ray or gamma-ray) photon beam is generated either from radioisotopes such as GADOLINIUM 153, IODINE 125, or Americanium 241 which emit GAMMA RAYS in the appropriate range; or from an X-ray tube which produces X-RAYS in the desired range. It is primarily used for quantitating BONE MINERAL CONTENT, especially for the diagnosis of OSTEOPOROSIS, and also in measuring BONE MINERALIZATION.
Tendency of the smooth muscle of the tracheobronchial tree to contract more intensely in response to a given stimulus than it does in the response seen in normal individuals. This condition is present in virtually all symptomatic patients with asthma. The most prominent manifestation of this smooth muscle contraction is a decrease in airway caliber that can be readily measured in the pulmonary function laboratory.
The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.
Devices for the compression of a blood vessel by application around an extremity to control the circulation and prevent the flow of blood to or from the distal area. (From Dorland, 28th ed)
Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.
Ultrasonography applying the Doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the Doppler shift frequency.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include CHRONIC BRONCHITIS and PULMONARY EMPHYSEMA.
Physiological processes and properties of the RESPIRATORY SYSTEM as a whole or of any of its parts.
A vein on either side of the body which is formed by the union of the external and internal iliac veins and passes upward to join with its fellow of the opposite side to form the inferior vena cava.
The measurement of subcutaneous fat located directly beneath the skin by grasping a fold of skin and subcutaneous fat between the thumb and forefinger and pulling it away from the underlying muscle tissue. The thickness of the double layer of skin and subcutaneous tissue is then read with a caliper. The five most frequently measured sites are the upper arm, below the scapula, above the hip bone, the abdomen, and the thigh. Its application is the determination of relative fatness, of changes in physical conditioning programs, and of the percentage of body fat in desirable body weight. (From McArdle, et al., Exercise Physiology, 2d ed, p496-8)
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
A short-acting beta-2 adrenergic agonist that is primarily used as a bronchodilator agent to treat ASTHMA. Albuterol is prepared as a racemic mixture of R(-) and S(+) stereoisomers. The stereospecific preparation of R(-) isomer of albuterol is referred to as levalbuterol.
A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.
The force per unit area that the air exerts on any surface in contact with it. Primarily used for articles pertaining to air pressure within a closed environment.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.
An NADPH-dependent enzyme that catalyzes the conversion of L-ARGININE and OXYGEN to produce CITRULLINE and NITRIC OXIDE.
The muscular membranous segment between the PHARYNX and the STOMACH in the UPPER GASTROINTESTINAL TRACT.
A nonapeptide messenger that is enzymatically produced from KALLIDIN in the blood where it is a potent but short-lived agent of arteriolar dilation and increased capillary permeability. Bradykinin is also released from MAST CELLS during asthma attacks, from gut walls as a gastrointestinal vasodilator, from damaged tissues as a pain signal, and may be a neurotransmitter.
An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)
Determination, by measurement or comparison with a standard, of the correct value of each scale reading on a meter or other measuring instrument; or determination of the settings of a control device that correspond to particular values of voltage, current, frequency or other output.
Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)
Material used for wrapping or binding any part of the body.
The tubular and cavernous organs and structures, by means of which pulmonary ventilation and gas exchange between ambient air and the blood are brought about.
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 ejection of gas or air through the mouth from the stomach.
Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)
An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness.
Confinement of an individual to bed for therapeutic or experimental reasons.
The act of BREATHING out.
A subtype of endothelin receptor found predominantly in the VASCULAR SMOOTH MUSCLE. It has a high affinity for ENDOTHELIN-1 and ENDOTHELIN-2.
The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.
The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.
Muscles forming the ABDOMINAL WALL including RECTUS ABDOMINIS, external and internal oblique muscles, transversus abdominis, and quadratus abdominis. (from Stedman, 25th ed)
A form of bronchial disorder with three distinct components: airway hyper-responsiveness (RESPIRATORY HYPERSENSITIVITY), airway INFLAMMATION, and intermittent AIRWAY OBSTRUCTION. It is characterized by spasmodic contraction of airway smooth muscle, WHEEZING, and dyspnea (DYSPNEA, PAROXYSMAL).
The act of constricting.
Ultrasonography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography is well-suited to identifying the location of high-velocity flow (such as in a stenosis) or of mapping the extent of flow in a certain region.
A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)
Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The formation or presence of a blood clot (THROMBUS) within a vein.
Apparatus and instruments that generate and operate with ELECTRICITY, and their electrical components.
The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
The recording of muscular movements. The apparatus is called a myograph, the record or tracing, a myogram. (From Stedman, 25th ed)
The amount of fat or lipid deposit at a site or an organ in the body, an indicator of body fat status.

Bioelectrical impedance plethysmographic analysis of body composition in critically injured and healthy subjects. (1/143)

BACKGROUND: Determination of body composition during critical illness is complex because of various patient-related and technical factors. Bioelectrical impedance is a promising technique for the analysis of body composition; however, its clinical utility in critically injured patients is unknown. OBJECTIVE: The purpose of this study was to compare bioelectrical impedance with metabolic activity in healthy and critically injured patients. If bioelectrical impedance accurately determines body composition during critical illness, the slope between body-composition variables and oxygen consumption would be the same in critically injured and healthy subjects. DESIGN: There is a strong linear relation between body composition and metabolic activity. In the present study, body composition (fat-free mass and body cell mass) was determined by using bioelectrical impedance and resting metabolic activity (metabolic rate and oxygen consumption) by using gas exchange analysis in a group of healthy and critically injured subjects. The relation between these variables was compared by using linear regression to a similar relation established by hydrostatic weighing in a large historical control group. RESULTS: The slope of the line relating fat-free mass to resting metabolic rate was the same in the healthy and critically ill groups (P = 0.62) and each was similar to the slope of the line for the control group. However, in 37% of the critically injured group, overhydration contributed to an increase in fat-free mass, disturbing the relation with resting metabolic rate. The slope of the line relating body cell mass to oxygen consumption in our healthy and critically ill groups was almost identical. CONCLUSION: These results support the use of bioelectrical impedance to determine body cell mass in healthy and critically ill subjects.  (+info)

Comparison of air-displacement plethysmography with hydrostatic weighing and bioelectrical impedance analysis for the assessment of body composition in healthy adults. (2/143)

BACKGROUND: Over the past decade, considerable attention has been paid to accurately measuring body composition in diverse populations. Recently, the use of air-displacement plethysmography (AP) was proposed as an accurate, comfortable, and accessible method of body-composition analysis. OBJECTIVE: The purpose of this study was to compare measurements of percentage body fat (%BF) by AP and 2 other established techniques, hydrostatic weighing (HW) and bioelectrical impedance analysis (BIA), in adults. DESIGN: The sample consisted of healthy men (n = 23) and women (n = 24). %BF was measured by AP, HW, and BIA. RESULTS: In the total group, %BF(AP) (25.0+/-8.9%) was not significantly different from %BF(HW) (25.1+/-7.7%) or %BF(BIA) (23.9+/-7.7%), and %BF(AP) was significantly correlated with %BF(HW) (r = 0.944, P < 0.001) and with %BF(BIA) (r = 0.859, P < 0.01). Compared with HW, AP underestimated %BF in men (by -1.24+/-3.12%) but overestimated %BF in women (by 1.02+/-2.48%), indicating a significant sex effect (P < 0.05). The differences in estimation between AP and BIA and between BIA and HW were not significantly different between the sexes. CONCLUSION: AP is an accurate method for assessing body composition in healthy adults. Future studies should assess further the cause of the individual variations with this new method.  (+info)

A new method of intraoperative hydraulic impedance measurement provides valuable prognostic information about infrainguinal graft patency. (3/143)

PURPOSE: Prognostic information about graft outcome, obtained by using a new method for intraoperative measurement of vascular impedance, was evaluated. METHODS: Hydraulic impedance was measured in 136 infrainguinal bypass grafts that were entered into a multicenter trial. Seventy femoropopliteal and 66 femorocrural polytetrafluoroethylene (PTFE) grafts were used. The arterial impedance measurement involved a silicon bypass graft temporarily inserted between the proximal and distal anastomoses sites. A flowmeter probe and a pressure transducer were incorporated into the tube. The digitally stored waveforms were subjected to a fast Fourier transformation and both input (Z(x)) and characteristic (Z(0)) impedances, as well as phase relations, were computed and related to graft outcome after 3 years. RESULTS: Significant prognostic information for both popliteal and crural grafts was provided by means of the phase angle of the first harmonic. Primary and secondary patency rates for popliteal bypasses were 45% +/- 1% and 65% +/- 2% for phase angles greater than -40 degrees (n = 57) and 37% +/- 1% and 40% +/- 1% for phase angles less than -40 degrees (n = 13, p(prim ) = not significant, p(sec) < 0.01). For crural grafts, the secondary patency rates were 49% +/- 1% and 61% +/- 2% for phase angles greater than -40 degrees (n = 53) and 15% +/- 1% and 0% for phase angles less than -40 degrees (n = 13, P <.01). All crural bypass grafts with phase angles less than -40 degrees occluded within 16 months. Steady flow resistance, as well as Z(x) and Z(0), failed to indicate a significant relation to graft prognosis. CONCLUSION: This method provides reliable prognostic information regarding graft patency and opens hydraulic impedance measurement to clinical surgery. The phase lag between flow and pressure curves, as expressed by the phase angle of the first harmonic, provides significant prognostic information.  (+info)

Second by second patterns in cortical electroencephalograph and systolic blood pressure during Cheyne-Stokes. (4/143)

Little is known about how arousal develops during the ventilatory phase of Cheyne-Stokes breathing. This study employs neural network analysis of electroencephalograms (EEGs) to describe these changes and relate them to changes in systolic blood pressure, which is probably a subcortical marker of arousal. Six patients with Cheyne-Stokes respiration (apnoea/hypopnoea index 32-69 h(-1)) caused by stable chronic heart failure underwent polysomnography including arterial beat-to-beat systolic blood pressure determination. Periods of 15 sequential apnoeas during nonrapid eye movement sleep were identified for each subject. For each apnoea, the EEG was examined second-by-second using neural net analysis from 28 s before to 28 s after apnoea termination (first return of oronasal airflow), and this was compared with the systolic blood pressure pattern. During the apnoeic phase, sleep deepened progressively. Arousal started to develop at or just before apnoea termination and progresses through the breathing phase. The rise and fall in the systolic blood pressure closely followed the rise and fall in electroencephalographic sleep depth. In conclusion, during Cheyne-Stokes breathing, cortical electroencephalographic arousal begins at or just before the resumption of breathing. Cortical electroencephalographic sleep depth changes are closely mirrored by changes in arterial systolic blood pressure, suggesting that the state changes in the cortical and basal brain structures may be synchronous.  (+info)

Monitoring equipment induced tachycardia in patients with minute ventilation rate-responsive pacemakers. (5/143)

Minute ventilation-sensing pacemakers enable the paced heart to respond to an increased workload. Two patients with such a pacemaker developed pacemaker-driven tachycardia when connected to an electrocardiogram (ECG) monitor also capable of documenting ventilatory frequency and ECG lead disconnection. This tachycardia stopped when the ECG leads were removed. These pacemakers and monitors emit a low-amplitude electrical current and measure the resultant impedence signal across the chest. When patients are connected to the monitor the pacemaker sensor summates both impedence signals and the paced heart rate is increased as a result.  (+info)

Quantitative general theory for periodic breathing in chronic heart failure and its clinical implications. (6/143)

BACKGROUND: In patients with chronic heart failure (CHF), periodic breathing (PB) predicts poor prognosis. Clinical studies have identified numerous risk factors for PB (which also includes Cheyne-Stokes respiration). Computer simulations have shown that oscillations can arise from delayed negative feedback. However, no simple general theory quantitatively explains PB and its mechanisms of treatment using widely-understood clinical concepts. Therefore, we introduce a new approach to the quantitative analysis of the dynamic physiology governing cardiorespiratory stability in CHF. METHODS AND RESULTS: An algebraic formula was derived (presented as a simple 2D plot), enabling prediction from easily acquired clinical data to determine whether respiration will be unstable. Clinical validation was performed in 20 patients with CHF (10 with PB and 10 without) and 10 healthy normal subjects. Measurements, including chemoreflex sensitivity (S) and delay (delta), alveolar volume (V(L)), and end-tidal CO(2) fraction (C), were applied to the stability formula. The breathing pattern was correctly predicted in 28 of the 30 subjects. The principal combined parameter (CS)x(delta/V(L)) was higher in patients with PB (14.2+/-3.0) than in those without PB (3.1+/-0.5; P:=0.0005) or in normal controls (2.4+/-0.5; P:=0.0003). This was because of differences in both chemoreflex sensitivity (1749+/-235 versus 620+/-103 and 526+/-104 L/min per atm CO(2); P:=0.0001 and P:<0.0001, respectively) and chemoreflex delay (0.53+/-0.06 vs 0.40+/-0.06 and 0.30+/-0.04 min; P:=NS and P:=0.02). CONCLUSION: This analytical approach identifies the physiological abnormalities that are important in the genesis of PB and explicitly defines the region of predicted instability. The clinical data identify chemoreflex gain and delay time (rather than hyperventilation or hypocapnia) as causes of PB.  (+info)

Cardiopulmonary adjustments following single high dosage administration of methylprednisolone in traumatized man. (7/143)

Pharmacologic doses of methylprednisolone sodium succinate were administered to 10 critically ill patients when the steroid was the only variable. Measurements of respiratory and circulatory physiologic parameters were obtained in all patients prior to injection and at 30 and 90 minutes following injection of methylprednisolone sodium succinate. A significant increase in Cardiac Index was seen (P less than .01) which appeared to be in association with a decrease in pulmonary vascular resistance (P less than .01) at a time when physiologic shunting of blood through the lungs increased (P less than .01). These changes imply improved perfusion of non- or poorly ventilated portions of the lungs. Four of ten patients demonstrated removal of lactate by the lung during the control period. Following methylprednisolone sodium succinate injection, 9 of 10 patients demonstrated production or a washout of lactate from the lungs.  (+info)

Response of the stroke volume and blood pressure of young patients with nonobstructive hypertrophic cardiomyopathy to exercise. (8/143)

Stroke volume (SV), cardiac output (CO) and systolic blood pressure (SBP) were measured during maximal symptom-limited bicycle exercise testing in 13 young patients (age, 11-26 years) with nonobstructive hypertrophic cardiomyopathy (HCM). SV was measured by impedance plethysmocardiography; %SVend, %COend, and %SBPend represent the ratio of the value at termination of the exercise to the respective value at rest. In all patients of HCM-I (the Cardiac Event Group, 3 patients) and 3 of HCM-II (the Non-Cardiac Event Group, 10 patients), the %SVend was less than 100%. The %SVend of HCM-I was significantly lower than the respective values of the HCM-II and Control groups. The %COend values of the HCM-I and HCM-II groups were each significantly lower than that of the Control. The %SBPend values of the HCM-I and HCM-II groups were each significantly lower than that of the Control. Among the HCM patients, the %SVend value was positively correlated with the %SBPend value. The patients who had more severe HCM had poorer exercise-induced increases in SV and SBP. These results suggest that sudden cardiac death in young HCM patients is associated with inhibition of the increase in SV upon exercise.  (+info)

Plethysmography is a non-invasive medical technique used to measure changes in volume or blood flow within an organ or body part, typically in the lungs or extremities. There are several types of plethysmography, including:

1. **Whole Body Plethysmography (WBP):** This type of plethysmography is used to assess lung function and volumes by measuring changes in pressure within a sealed chamber that contains the patient's entire body except for their head. The patient breathes normally while wearing a nose clip, allowing technicians to analyze respiratory patterns, airflow, and lung volume changes.
2. **Segmental or Local Plethysmography:** This technique measures volume or blood flow changes in specific body parts, such as the limbs or digits. It can help diagnose and monitor conditions affecting peripheral circulation, like deep vein thrombosis, arterial occlusive disease, or Raynaud's phenomenon.
3. **Impedance Plethysmography (IPG):** This non-invasive method uses electrical impedance to estimate changes in blood volume within an organ or body part. By applying a small electrical current and measuring the opposition to flow (impedance), technicians can determine variations in blood volume, which can help diagnose conditions like deep vein thrombosis or heart failure.
4. **Optical Plethysmography:** This technique uses light to measure changes in blood volume, typically in the skin or mucous membranes. By shining a light on the area and analyzing the reflected or transmitted light, technicians can detect variations in blood volume related to cardiac output, respiration, or other physiological factors.

Overall, plethysmography is an essential tool for diagnosing and monitoring various medical conditions affecting circulation, respiratory function, and organ volumes.

Impedance plethysmography is a non-invasive method used to measure changes in blood volume or flow in a particular area of the body. It works by passing a small electrical current through the tissue and measuring the opposition (impedance) to that current, which varies with the amount of blood present in the area.

In impedance cardiography, this technique is used to estimate cardiac output, stroke volume, and other hemodynamic parameters. The changes in impedance are measured across the chest wall, which correlate with the ventricular ejection of blood during each heartbeat. This allows for the calculation of various cardiovascular variables, such as the amount of blood pumped by the heart per minute (cardiac output) and the resistance to blood flow in the systemic circulation (systemic vascular resistance).

Impedance plethysmography is a safe and reliable method for assessing cardiovascular function, and it has been widely used in clinical settings to evaluate patients with various cardiovascular disorders, including heart failure, hypertension, and peripheral arterial disease.

Electric impedance is a measure of opposition to the flow of alternating current (AC) in an electrical circuit or component, caused by both resistance (ohmic) and reactance (capacitive and inductive). It is expressed as a complex number, with the real part representing resistance and the imaginary part representing reactance. The unit of electric impedance is the ohm (Ω).

In the context of medical devices, electric impedance may be used to measure various physiological parameters, such as tissue conductivity or fluid composition. For example, bioelectrical impedance analysis (BIA) uses electrical impedance to estimate body composition, including fat mass and lean muscle mass. Similarly, electrical impedance tomography (EIT) is a medical imaging technique that uses electric impedance to create images of internal organs and tissues.

Whole-body plethysmography is a non-invasive medical technique used to measure changes in the volume of air in the lungs and chest during breathing. It is often utilized in the diagnosis and assessment of various respiratory disorders such as chronic obstructive pulmonary disease (COPD), asthma, and restrictive lung diseases.

During whole-body plethysmography, the patient enters a sealed, clear chamber, usually in a standing or sitting position. The patient is instructed to breathe normally while the machine measures changes in pressure within the chamber as the chest and abdomen move during respiration. These measurements are then used to calculate lung volume, airflow, and other respiratory parameters.

This technique provides valuable information about the functional status of the lungs and can help healthcare providers make informed decisions regarding diagnosis, treatment planning, and disease monitoring.

Impedance cardiography is a non-invasive method to measure cardiac output and systemic vascular resistance. It uses low-frequency electrical currents passed through the thorax to measure changes in impedance or resistance to flow during each heartbeat. This allows for the calculation of stroke volume and cardiac output. Impedance cardiography can provide continuous, real-time monitoring of cardiovascular function, making it useful in critical care settings and for tracking changes in patients with heart failure or other cardiovascular conditions.

The forearm is the region of the upper limb between the elbow and the wrist. It consists of two bones, the radius and ulna, which are located side by side and run parallel to each other. The forearm is responsible for movements such as flexion, extension, supination, and pronation of the hand and wrist.

Regional blood flow (RBF) refers to the rate at which blood flows through a specific region or organ in the body, typically expressed in milliliters per minute per 100 grams of tissue (ml/min/100g). It is an essential physiological parameter that reflects the delivery of oxygen and nutrients to tissues while removing waste products. RBF can be affected by various factors such as metabolic demands, neural regulation, hormonal influences, and changes in blood pressure or vascular resistance. Measuring RBF is crucial for understanding organ function, diagnosing diseases, and evaluating the effectiveness of treatments.

Dielectric spectroscopy is a type of material characterization technique that measures the dielectric properties of a material as a function of frequency. The dielectric property of a material refers to its ability to store electrical energy in the form of polarization when an external electric field is applied. In dielectric spectroscopy, the material's response to an alternating electric field is measured, and the resulting complex permittivity (which includes both real and imaginary components) is used to characterize the material's dielectric behavior.

The technique involves applying a small amplitude AC voltage to the material while measuring the current flow through it. The frequency of the applied voltage can be varied over a wide range, typically from millihertz to gigahertz. By analyzing the phase shift and amplitude of the resulting current, the complex permittivity of the material can be determined as a function of frequency.

Dielectric spectroscopy is widely used in materials science, physics, chemistry, and biology to study the structure, dynamics, and composition of various materials, including polymers, ceramics, glasses, colloids, and biological tissues. The technique can provide valuable information about the material's molecular mobility, relaxation processes, conductivity, and other dielectric properties, which can be used for quality control, process monitoring, and fundamental research.

Airway resistance is a measure of the opposition to airflow during breathing, which is caused by the friction between the air and the walls of the respiratory tract. It is an important parameter in respiratory physiology because it can affect the work of breathing and gas exchange.

Airway resistance is usually expressed in units of cm H2O/L/s or Pa·s/m, and it can be measured during spontaneous breathing or during forced expiratory maneuvers, such as those used in pulmonary function testing. Increased airway resistance can result from a variety of conditions, including asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and bronchiectasis. Decreased airway resistance can be seen in conditions such as emphysema or after a successful bronchodilator treatment.

Respiratory mechanics refers to the biomechanical properties and processes that involve the movement of air through the respiratory system during breathing. It encompasses the mechanical behavior of the lungs, chest wall, and the muscles of respiration, including the diaphragm and intercostal muscles.

Respiratory mechanics includes several key components:

1. **Compliance**: The ability of the lungs and chest wall to expand and recoil during breathing. High compliance means that the structures can easily expand and recoil, while low compliance indicates greater resistance to expansion and recoil.
2. **Resistance**: The opposition to airflow within the respiratory system, primarily due to the friction between the air and the airway walls. Airway resistance is influenced by factors such as airway diameter, length, and the viscosity of the air.
3. **Lung volumes and capacities**: These are the amounts of air present in the lungs during different phases of the breathing cycle. They include tidal volume (the amount of air inspired or expired during normal breathing), inspiratory reserve volume (additional air that can be inspired beyond the tidal volume), expiratory reserve volume (additional air that can be exhaled beyond the tidal volume), and residual volume (the air remaining in the lungs after a forced maximum exhalation).
4. **Work of breathing**: The energy required to overcome the resistance and elastic forces during breathing. This work is primarily performed by the respiratory muscles, which contract to generate negative intrathoracic pressure and expand the chest wall, allowing air to flow into the lungs.
5. **Pressure-volume relationships**: These describe how changes in lung volume are associated with changes in pressure within the respiratory system. Important pressure components include alveolar pressure (the pressure inside the alveoli), pleural pressure (the pressure between the lungs and the chest wall), and transpulmonary pressure (the difference between alveolar and pleural pressures).

Understanding respiratory mechanics is crucial for diagnosing and managing various respiratory disorders, such as chronic obstructive pulmonary disease (COPD), asthma, and restrictive lung diseases.

The thorax is the central part of the human body, located between the neck and the abdomen. In medical terms, it refers to the portion of the body that contains the heart, lungs, and associated structures within a protective cage made up of the sternum (breastbone), ribs, and thoracic vertebrae. The thorax is enclosed by muscles and protected by the ribcage, which helps to maintain its structural integrity and protect the vital organs contained within it.

The thorax plays a crucial role in respiration, as it allows for the expansion and contraction of the lungs during breathing. This movement is facilitated by the flexible nature of the ribcage, which expands and contracts with each breath, allowing air to enter and exit the lungs. Additionally, the thorax serves as a conduit for major blood vessels, such as the aorta and vena cava, which carry blood to and from the heart and the rest of the body.

Understanding the anatomy and function of the thorax is essential for medical professionals, as many conditions and diseases can affect this region of the body. These may include respiratory disorders such as pneumonia or chronic obstructive pulmonary disease (COPD), cardiovascular conditions like heart attacks or aortic aneurysms, and musculoskeletal issues involving the ribs, spine, or surrounding muscles.

In medical terms, the leg refers to the lower portion of the human body that extends from the knee down to the foot. It includes the thigh (femur), lower leg (tibia and fibula), foot, and ankle. The leg is primarily responsible for supporting the body's weight and enabling movements such as standing, walking, running, and jumping.

The leg contains several important structures, including bones, muscles, tendons, ligaments, blood vessels, nerves, and joints. These structures work together to provide stability, support, and mobility to the lower extremity. Common medical conditions that can affect the leg include fractures, sprains, strains, infections, peripheral artery disease, and neurological disorders.

Vascular resistance is a measure of the opposition to blood flow within a vessel or a group of vessels, typically expressed in units of mmHg/(mL/min) or sometimes as dynes*sec/cm^5. It is determined by the diameter and length of the vessels, as well as the viscosity of the blood flowing through them. In general, a decrease in vessel diameter, an increase in vessel length, or an increase in blood viscosity will result in an increase in vascular resistance, while an increase in vessel diameter, a decrease in vessel length, or a decrease in blood viscosity will result in a decrease in vascular resistance. Vascular resistance is an important concept in the study of circulation and cardiovascular physiology because it plays a key role in determining blood pressure and blood flow within the body.

Lung volume measurements are clinical tests that determine the amount of air inhaled, exhaled, and present in the lungs at different times during the breathing cycle. These measurements include:

1. Tidal Volume (TV): The amount of air inhaled or exhaled during normal breathing, usually around 500 mL in resting adults.
2. Inspiratory Reserve Volume (IRV): The additional air that can be inhaled after a normal inspiration, approximately 3,000 mL in adults.
3. Expiratory Reserve Volume (ERV): The extra air that can be exhaled after a normal expiration, about 1,000-1,200 mL in adults.
4. Residual Volume (RV): The air remaining in the lungs after a maximal exhalation, approximately 1,100-1,500 mL in adults.
5. Total Lung Capacity (TLC): The total amount of air the lungs can hold at full inflation, calculated as TV + IRV + ERV + RV, around 6,000 mL in adults.
6. Functional Residual Capacity (FRC): The volume of air remaining in the lungs after a normal expiration, equal to ERV + RV, about 2,100-2,700 mL in adults.
7. Inspiratory Capacity (IC): The maximum amount of air that can be inhaled after a normal expiration, equal to TV + IRV, around 3,500 mL in adults.
8. Vital Capacity (VC): The total volume of air that can be exhaled after a maximal inspiration, calculated as IC + ERV, approximately 4,200-5,600 mL in adults.

These measurements help assess lung function and identify various respiratory disorders such as chronic obstructive pulmonary disease (COPD), asthma, and restrictive lung diseases.

nitroprusside (ni-troe-rus-ide)

A rapid-acting vasodilator used in the management of severe hypertension, acute heart failure, and to reduce afterload in patients undergoing cardiac surgery. It is a potent arterial and venous dilator that decreases preload and afterload, thereby reducing myocardial oxygen demand. Nitroprusside is metabolized to cyanide, which must be monitored closely during therapy to prevent toxicity.

Pharmacologic class: Peripheral vasodilators

Therapeutic class: Antihypertensives, Vasodilators

Medical Categories: Cardiovascular Drugs, Hypertension Agents

Vasodilation is the widening or increase in diameter of blood vessels, particularly the involuntary relaxation of the smooth muscle in the tunica media (middle layer) of the arteriole walls. This results in an increase in blood flow and a decrease in vascular resistance. Vasodilation can occur due to various physiological and pathophysiological stimuli, such as local metabolic demands, neural signals, or pharmacological agents. It plays a crucial role in regulating blood pressure, tissue perfusion, and thermoregulation.

Omega-N-Methylarginine (also known as NG, NG-dimethyl-L-arginine) is not a commonly used medical term and it's not a well-known compound in medicine. However, it is a form of methylated arginine that can be found in the body.

Methylated arginines are a group of compounds that are generated through the post-translational modification of proteins by enzymes called protein arginine methyltransferases (PRMTs). These modifications play important roles in various cellular processes, including gene expression and signal transduction.

Omega-N-Methylarginine is a specific type of methylated arginine that has two methyl groups attached to the nitrogen atom at the end of the side chain (omega position) of the amino acid arginine. It can be formed by the action of PRMTs on proteins, and it may have various biological functions in the body. However, its specific medical significance is not well-established, and more research is needed to fully understand its role in health and disease.

Medical Definition of Respiration:

Respiration, in physiology, is the process by which an organism takes in oxygen and gives out carbon dioxide. It's also known as breathing. This process is essential for most forms of life because it provides the necessary oxygen for cellular respiration, where the cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), and releases waste products, primarily carbon dioxide.

In humans and other mammals, respiration is a two-stage process:

1. Breathing (or external respiration): This involves the exchange of gases with the environment. Air enters the lungs through the mouth or nose, then passes through the pharynx, larynx, trachea, and bronchi, finally reaching the alveoli where the actual gas exchange occurs. Oxygen from the inhaled air diffuses into the blood, while carbon dioxide, a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled.

2. Cellular respiration (or internal respiration): This is the process by which cells convert glucose and other nutrients into ATP, water, and carbon dioxide in the presence of oxygen. The carbon dioxide produced during this process then diffuses out of the cells and into the bloodstream to be exhaled during breathing.

In summary, respiration is a vital physiological function that enables organisms to obtain the necessary oxygen for cellular metabolism while eliminating waste products like carbon dioxide.

Veins are blood vessels that carry deoxygenated blood from the tissues back to the heart. They have a lower pressure than arteries and contain valves to prevent the backflow of blood. Veins have a thin, flexible wall with a larger lumen compared to arteries, allowing them to accommodate more blood volume. The color of veins is often blue or green due to the absorption characteristics of light and the reduced oxygen content in the blood they carry.

Body composition refers to the relative proportions of different components that make up a person's body, including fat mass, lean muscle mass, bone mass, and total body water. It is an important measure of health and fitness, as changes in body composition can indicate shifts in overall health status. For example, an increase in fat mass and decrease in lean muscle mass can be indicative of poor nutrition, sedentary behavior, or certain medical conditions.

There are several methods for measuring body composition, including:

1. Bioelectrical impedance analysis (BIA): This method uses low-level electrical currents to estimate body fat percentage based on the conductivity of different tissues.
2. Dual-energy X-ray absorptiometry (DXA): This method uses low-dose X-rays to measure bone density and body composition, including lean muscle mass and fat distribution.
3. Hydrostatic weighing: This method involves submerging a person in water and measuring their weight underwater to estimate body density and fat mass.
4. Air displacement plethysmography (ADP): This method uses air displacement to measure body volume and density, which can be used to estimate body composition.

Understanding body composition can help individuals make informed decisions about their health and fitness goals, as well as provide valuable information for healthcare providers in the management of chronic diseases such as obesity, diabetes, and heart disease.

Tidal volume (Vt) is the amount of air that moves into or out of the lungs during normal, resting breathing. It is the difference between the volume of air in the lungs at the end of a normal expiration and the volume at the end of a normal inspiration. In other words, it's the volume of each breath you take when you are not making any effort to breathe more deeply.

The average tidal volume for an adult human is around 500 milliliters (ml) per breath, but this can vary depending on factors such as age, sex, size, and fitness level. During exercise or other activities that require increased oxygen intake, tidal volume may increase to meet the body's demands for more oxygen.

Tidal volume is an important concept in respiratory physiology and clinical medicine, as it can be used to assess lung function and diagnose respiratory disorders such as chronic obstructive pulmonary disease (COPD) or asthma.

An electrode is a medical device that can conduct electrical currents and is used to transmit or receive electrical signals, often in the context of medical procedures or treatments. In a medical setting, electrodes may be used for a variety of purposes, such as:

1. Recording electrical activity in the body: Electrodes can be attached to the skin or inserted into body tissues to measure electrical signals produced by the heart, brain, muscles, or nerves. This information can be used to diagnose medical conditions, monitor the effectiveness of treatments, or guide medical procedures.
2. Stimulating nerve or muscle activity: Electrodes can be used to deliver electrical impulses to nerves or muscles, which can help to restore function or alleviate symptoms in people with certain medical conditions. For example, electrodes may be used to stimulate the nerves that control bladder function in people with spinal cord injuries, or to stimulate muscles in people with muscle weakness or paralysis.
3. Administering treatments: Electrodes can also be used to deliver therapeutic treatments, such as transcranial magnetic stimulation (TMS) for depression or deep brain stimulation (DBS) for movement disorders like Parkinson's disease. In these procedures, electrodes are implanted in specific areas of the brain and connected to a device that generates electrical impulses, which can help to regulate abnormal brain activity and improve symptoms.

Overall, electrodes play an important role in many medical procedures and treatments, allowing healthcare professionals to diagnose and treat a wide range of conditions that affect the body's electrical systems.

Pulmonary ventilation, also known as pulmonary respiration or simply ventilation, is the process of moving air into and out of the lungs to facilitate gas exchange. It involves two main phases: inhalation (or inspiration) and exhalation (or expiration). During inhalation, the diaphragm and external intercostal muscles contract, causing the chest volume to increase and the pressure inside the chest to decrease, which then draws air into the lungs. Conversely, during exhalation, these muscles relax, causing the chest volume to decrease and the pressure inside the chest to increase, which pushes air out of the lungs. This process ensures that oxygen-rich air from the atmosphere enters the alveoli (air sacs in the lungs), where it can diffuse into the bloodstream, while carbon dioxide-rich air from the bloodstream in the capillaries surrounding the alveoli is expelled out of the body.

Body water refers to the total amount of water present in the human body. It is an essential component of life and makes up about 60-70% of an adult's body weight. Body water is distributed throughout various fluid compartments within the body, including intracellular fluid (water inside cells), extracellular fluid (water outside cells), and transcellular fluid (water found in specific bodily spaces such as the digestive tract, eyes, and joints). Maintaining proper hydration and balance of body water is crucial for various physiological processes, including temperature regulation, nutrient transportation, waste elimination, and overall health.

Vasodilator agents are pharmacological substances that cause the relaxation or widening of blood vessels by relaxing the smooth muscle in the vessel walls. This results in an increase in the diameter of the blood vessels, which decreases vascular resistance and ultimately reduces blood pressure. Vasodilators can be further classified based on their site of action:

1. Systemic vasodilators: These agents cause a generalized relaxation of the smooth muscle in the walls of both arteries and veins, resulting in a decrease in peripheral vascular resistance and preload (the volume of blood returning to the heart). Examples include nitroglycerin, hydralazine, and calcium channel blockers.
2. Arterial vasodilators: These agents primarily affect the smooth muscle in arterial vessel walls, leading to a reduction in afterload (the pressure against which the heart pumps blood). Examples include angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and direct vasodilators like sodium nitroprusside.
3. Venous vasodilators: These agents primarily affect the smooth muscle in venous vessel walls, increasing venous capacitance and reducing preload. Examples include nitroglycerin and other organic nitrates.

Vasodilator agents are used to treat various cardiovascular conditions such as hypertension, heart failure, angina, and pulmonary arterial hypertension. It is essential to monitor their use carefully, as excessive vasodilation can lead to orthostatic hypotension, reflex tachycardia, or fluid retention.

Total Lung Capacity (TLC) is the maximum volume of air that can be contained within the lungs at the end of a maximal inspiration. It includes all of the following lung volumes: tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. TLC can be measured directly using gas dilution techniques or indirectly by adding residual volume to vital capacity. Factors that affect TLC include age, sex, height, and lung health status.

Hyperemia is a medical term that refers to an increased flow or accumulation of blood in certain capillaries or vessels within an organ or tissue, resulting in its redness and warmth. This can occur due to various reasons such as physical exertion, emotional excitement, local injury, or specific medical conditions.

There are two types of hyperemia: active and passive. Active hyperemia is a physiological response where the blood flow increases as a result of the metabolic demands of the organ or tissue. For example, during exercise, muscles require more oxygen and nutrients, leading to an increase in blood flow. Passive hyperemia, on the other hand, occurs when there is a blockage in the venous outflow, causing the blood to accumulate in the affected area. This can result from conditions like thrombosis or vasoconstriction.

It's important to note that while hyperemia itself is not a disease, it can be a symptom of various underlying medical conditions and should be evaluated by a healthcare professional if it persists or is accompanied by other symptoms.

Methacholine chloride is a medication that is used as a diagnostic tool to help identify and assess the severity of asthma or other respiratory conditions that cause airway hyperresponsiveness. It is a synthetic derivative of acetylcholine, which is a neurotransmitter that causes smooth muscle contraction in the body.

When methacholine chloride is inhaled, it stimulates the muscarinic receptors in the airways, causing them to constrict or narrow. This response is measured and used to determine the degree of airway hyperresponsiveness, which can help diagnose asthma and assess its severity.

The methacholine challenge test involves inhaling progressively higher doses of methacholine chloride until a significant decrease in lung function is observed or until a maximum dose is reached. The test results are then used to guide treatment decisions and monitor the effectiveness of therapy. It's important to note that this test should be conducted under the supervision of a healthcare professional, as it carries some risks, including bronchoconstriction and respiratory distress.

Functional Residual Capacity (FRC) is the volume of air that remains in the lungs after normal expiration during quiet breathing. It represents the sum of the residual volume (RV) and the expiratory reserve volume (ERV). The FRC is approximately 2.5-3.5 liters in a healthy adult. This volume of air serves to keep the alveoli open and maintain oxygenation during periods of quiet breathing, as well as providing a reservoir for additional ventilation during increased activity or exercise.

The thoracic wall refers to the anatomical structure that surrounds and protects the chest cavity or thorax, which contains the lungs, heart, and other vital organs. It is composed of several components:

1. Skeletal framework: This includes the 12 pairs of ribs, the sternum (breastbone) in the front, and the thoracic vertebrae in the back. The upper seven pairs of ribs are directly attached to the sternum in the front through costal cartilages. The lower five pairs of ribs are not directly connected to the sternum but are joined to the ribs above them.
2. Muscles: The thoracic wall contains several muscles, including the intercostal muscles (located between the ribs), the scalene muscles (at the side and back of the neck), and the serratus anterior muscle (on the sides of the chest). These muscles help in breathing by expanding and contracting the ribcage.
3. Soft tissues: The thoracic wall also contains various soft tissues, such as fascia, nerves, blood vessels, and fat. These structures support the functioning of the thoracic organs and contribute to the overall stability and protection of the chest cavity.

The primary function of the thoracic wall is to protect the vital organs within the chest cavity while allowing for adequate movement during respiration. Additionally, it provides a stable base for the attachment of various muscles involved in upper limb movement and posture.

Blood pressure is the force exerted by circulating blood on the walls of the blood vessels. It is measured in millimeters of mercury (mmHg) and is given as two figures:

1. Systolic pressure: This is the pressure when the heart pushes blood out into the arteries.
2. Diastolic pressure: This is the pressure when the heart rests between beats, allowing it to fill with blood.

Normal blood pressure for adults is typically around 120/80 mmHg, although this can vary slightly depending on age, sex, and other factors. High blood pressure (hypertension) is generally considered to be a reading of 130/80 mmHg or higher, while low blood pressure (hypotension) is usually defined as a reading below 90/60 mmHg. It's important to note that blood pressure can fluctuate throughout the day and may be affected by factors such as stress, physical activity, and medication use.

Tomography is a medical imaging technique used to produce cross-sectional images or slices of specific areas of the body. This technique uses various forms of radiation (X-rays, gamma rays) or sound waves (ultrasound) to create detailed images of the internal structures, such as organs, bones, and tissues. Common types of tomography include Computerized Tomography (CT), Positron Emission Tomography (PET), and Magnetic Resonance Imaging (MRI). The primary advantage of tomography is its ability to provide clear and detailed images of internal structures, allowing healthcare professionals to accurately diagnose and monitor a wide range of medical conditions.

Respiratory Function Tests (RFTs) are a group of medical tests that measure how well your lungs take in and exhale air, and how well they transfer oxygen and carbon dioxide into and out of your blood. They can help diagnose certain lung disorders, measure the severity of lung disease, and monitor response to treatment.

RFTs include several types of tests, such as:

1. Spirometry: This test measures how much air you can exhale and how quickly you can do it. It's often used to diagnose and monitor conditions like asthma, chronic obstructive pulmonary disease (COPD), and other lung diseases.
2. Lung volume testing: This test measures the total amount of air in your lungs. It can help diagnose restrictive lung diseases, such as pulmonary fibrosis or sarcoidosis.
3. Diffusion capacity testing: This test measures how well oxygen moves from your lungs into your bloodstream. It's often used to diagnose and monitor conditions like pulmonary fibrosis, interstitial lung disease, and other lung diseases that affect the ability of the lungs to transfer oxygen to the blood.
4. Bronchoprovocation testing: This test involves inhaling a substance that can cause your airways to narrow, such as methacholine or histamine. It's often used to diagnose and monitor asthma.
5. Exercise stress testing: This test measures how well your lungs and heart work together during exercise. It's often used to diagnose lung or heart disease.

Overall, Respiratory Function Tests are an important tool for diagnosing and managing a wide range of lung conditions.

Acoustic impedance tests are diagnostic procedures used to measure the impedance or resistance of various parts of the ear to sound waves. These tests are often used to assess hearing function and diagnose any issues related to the middle ear, such as fluid buildup or problems with the eardrum.

The most common type of acoustic impedance test is tympanometry, which measures the mobility of the eardrum and the middle ear system by creating variations in air pressure within the ear canal. During this test, a small probe is inserted into the ear canal, and sound waves are generated while the pressure is varied. The resulting measurements provide information about the condition of the middle ear and can help identify any issues that may be affecting hearing.

Another type of acoustic impedance test is acoustic reflex testing, which measures the body's natural response to loud sounds. This involves measuring the contraction of the stapedius muscle in the middle ear, which occurs in response to loud noises. By measuring the strength and timing of this reflex, audiologists can gain additional insights into the functioning of the middle ear and identify any abnormalities that may be present.

Overall, acoustic impedance tests are important tools for diagnosing hearing problems and identifying any underlying issues in the middle ear. They are often used in conjunction with other hearing tests to provide a comprehensive assessment of an individual's hearing function.

Venous pressure is the pressure exerted on the walls of a vein, which varies depending on several factors such as the volume and flow of blood within the vein, the contractile state of the surrounding muscles, and the position of the body. In clinical settings, venous pressure is often measured in the extremities (e.g., arms or legs) to assess the functioning of the cardiovascular system.

Central venous pressure (CVP) is a specific type of venous pressure that refers to the pressure within the large veins that enter the right atrium of the heart. CVP is an important indicator of right heart function and fluid status, as it reflects the amount of blood returning to the heart and the ability of the heart to pump it forward. Normal CVP ranges from 0 to 8 mmHg (millimeters of mercury) in adults.

Elevated venous pressure can be caused by various conditions such as heart failure, obstruction of blood flow, or fluid overload, while low venous pressure may indicate dehydration or blood loss. Accurate measurement and interpretation of venous pressure require specialized equipment and knowledge, and are typically performed by healthcare professionals in a clinical setting.

Hemodynamics is the study of how blood flows through the cardiovascular system, including the heart and the vascular network. It examines various factors that affect blood flow, such as blood volume, viscosity, vessel length and diameter, and pressure differences between different parts of the circulatory system. Hemodynamics also considers the impact of various physiological and pathological conditions on these variables, and how they in turn influence the function of vital organs and systems in the body. It is a critical area of study in fields such as cardiology, anesthesiology, and critical care medicine.

Intra-arterial infusion is a medical procedure in which a liquid medication or fluid is delivered directly into an artery. This technique is used to deliver drugs directly to a specific organ or region of the body, bypassing the usual systemic circulation and allowing for higher concentrations of the drug to reach the target area. It is often used in cancer treatment to deliver chemotherapeutic agents directly to tumors, as well as in other conditions such as severe infections or inflammation.

Intra-arterial infusions are typically administered through a catheter that is inserted into an artery, usually under the guidance of imaging techniques such as fluoroscopy, CT, or MRI. The procedure requires careful monitoring and precise control to ensure proper placement of the catheter and accurate delivery of the medication.

It's important to note that intra-arterial infusions are different from intra venous (IV) infusions, where medications are delivered into a vein instead of an artery. The choice between intra-arterial and intra-venous infusion depends on various factors such as the type of medication being used, the location of the target area, and the patient's overall medical condition.

Blood flow velocity is the speed at which blood travels through a specific part of the vascular system. It is typically measured in units of distance per time, such as centimeters per second (cm/s) or meters per second (m/s). Blood flow velocity can be affected by various factors, including cardiac output, vessel diameter, and viscosity of the blood. Measuring blood flow velocity is important in diagnosing and monitoring various medical conditions, such as heart disease, stroke, and peripheral vascular disease.

Oscillometry is a non-invasive method to measure various mechanical properties of the respiratory system, including lung volumes and airway resistance. It involves applying small pressure oscillations to the airways and measuring the resulting flow or volume changes. The technique can be used to assess lung function in patients with obstructive or restrictive lung diseases, as well as in healthy individuals. Oscillometry is often performed during tidal breathing, making it a comfortable method for both children and adults who may have difficulty performing traditional spirometry maneuvers.

Vascular capacitance is a term used in physiology to describe the ability of blood vessels, particularly veins, to expand and accommodate changes in blood volume. It is the measure of the volume of blood that a vessel can hold for each unit increase in pressure. A larger capacitance means that the blood vessels can store more blood at lower pressures.

In simpler terms, vascular capacitance refers to the compliance or distensibility of the blood vessels. When the heart pumps blood into the arteries, some of it is immediately used by the body's tissues for various functions, while the remaining blood is stored in the veins until needed. The more compliant or distensible the veins are, the greater their capacity to store blood and maintain a relatively stable blood pressure.

Therefore, vascular capacitance plays an essential role in regulating blood pressure and ensuring adequate blood flow to various organs and tissues in the body. Factors that can affect vascular capacitance include age, overall health status, and certain medical conditions such as heart failure or cirrhosis of the liver.

Hand-arm vibration syndrome (HAVS) is a disorder that affects the nerves, blood vessels, muscles, and joints of the hands and arms. It's primarily caused by prolonged exposure to high levels of hand-transmitted vibration, such as from operating power tools or machinery that vibrate.

The symptoms of HAVS can include:

1. Numbness, tingling, or loss of sensation in the fingers.
2. Fingertip color changes (blanching) when exposed to cold.
3. Impaired blood flow, leading to finger blotchiness and skin color changes.
4. Reduced hand grip strength and coordination.
5. Pain and stiffness in the hands and arms.

The symptoms can develop gradually over time and may not be immediately noticeable. Early recognition and limiting exposure to vibration sources are crucial for preventing further progression of HAVS.

Venous insufficiency is a medical condition that occurs when the veins, particularly in the legs, have difficulty returning blood back to the heart due to impaired valve function or obstruction in the vein. This results in blood pooling in the veins, leading to symptoms such as varicose veins, swelling, skin changes, and ulcers. Prolonged venous insufficiency can cause chronic pain and affect the quality of life if left untreated.

Reproducibility of results in a medical context refers to the ability to obtain consistent and comparable findings when a particular experiment or study is repeated, either by the same researcher or by different researchers, following the same experimental protocol. It is an essential principle in scientific research that helps to ensure the validity and reliability of research findings.

In medical research, reproducibility of results is crucial for establishing the effectiveness and safety of new treatments, interventions, or diagnostic tools. It involves conducting well-designed studies with adequate sample sizes, appropriate statistical analyses, and transparent reporting of methods and findings to allow other researchers to replicate the study and confirm or refute the results.

The lack of reproducibility in medical research has become a significant concern in recent years, as several high-profile studies have failed to produce consistent findings when replicated by other researchers. This has led to increased scrutiny of research practices and a call for greater transparency, rigor, and standardization in the conduct and reporting of medical research.

Postphlebitic syndrome, also known as postthrombotic syndrome or post-thrombotic limb, is a long-term complication that can occur after deep vein thrombosis (DVT). It's characterized by chronic venous insufficiency due to damage in the valves and walls of the affected veins. This results in impaired return of blood from the extremities back to the heart, leading to symptoms such as:

1. Swelling (edema) in the affected limb, usually the lower leg or calf.
2. Pain, aching, or cramping in the legs.
3. Heaviness or fatigue in the legs.
4. Skin changes like redness, warmth, or itchiness.
5. Development of venous ulcers or sores, particularly around the ankles.

The severity of postphlebitic syndrome can vary from mild to severe and may significantly impact a person's quality of life. Risk factors for developing this condition include having had a previous DVT, obesity, older age, lack of physical activity, and a family history of blood clotting disorders. Early diagnosis and appropriate management of deep vein thrombosis can help reduce the risk of developing postphlebitic syndrome.

Thrombophlebitis is a medical condition characterized by the inflammation and clotting of blood in a vein, usually in the legs. The term thrombophlebitis comes from two words: "thrombo" which means blood clot, and "phlebitis" which refers to inflammation of the vein.

The condition can occur in superficial or deep veins. Superficial thrombophlebitis affects the veins just below the skin's surface, while deep vein thrombophlebitis (DVT) occurs in the deeper veins. DVT is a more serious condition as it can lead to complications such as pulmonary embolism if the blood clot breaks off and travels to the lungs.

Symptoms of thrombophlebitis may include redness, warmth, pain, swelling, or discomfort in the affected area. In some cases, there may be visible surface veins that are hard, tender, or ropy to touch. If left untreated, thrombophlebitis can lead to chronic venous insufficiency and other long-term complications. Treatment typically involves medications such as anticoagulants, antiplatelet agents, or thrombolytics, along with compression stockings and other supportive measures.

Acetylcholine is a neurotransmitter, a type of chemical messenger that transmits signals across a chemical synapse from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. It is involved in both peripheral and central nervous system functions.

In the peripheral nervous system, acetylcholine acts as a neurotransmitter at the neuromuscular junction, where it transmits signals from motor neurons to activate muscles. Acetylcholine also acts as a neurotransmitter in the autonomic nervous system, where it is involved in both the sympathetic and parasympathetic systems.

In the central nervous system, acetylcholine plays a role in learning, memory, attention, and arousal. Disruptions in cholinergic neurotransmission have been implicated in several neurological disorders, including Alzheimer's disease, Parkinson's disease, and myasthenia gravis.

Acetylcholine is synthesized from choline and acetyl-CoA by the enzyme choline acetyltransferase and is stored in vesicles at the presynaptic terminal of the neuron. When a nerve impulse arrives, the vesicles fuse with the presynaptic membrane, releasing acetylcholine into the synapse. The acetylcholine then binds to receptors on the postsynaptic membrane, triggering a response in the target cell. Acetylcholine is subsequently degraded by the enzyme acetylcholinesterase, which terminates its action and allows for signal transduction to be repeated.

Fluid shifts, in a medical context, refer to the movement or redistribution of fluids between different compartments within the body. The human body is composed of two main fluid compartments: the intracellular fluid (ICF), which is present inside the cells, and the extracellular fluid (ECF), which is outside the cells. The ECF is further divided into interstitial fluid (present in the spaces between cells) and intravascular fluid (present within the blood vessels).

Fluid shifts can occur due to various physiological and pathological conditions, such as changes in hydrostatic pressure, oncotic pressure, or permeability of the capillary membranes. These shifts can have significant impacts on various body systems, particularly the cardiovascular, respiratory, and renal systems. For example, fluid shifting from the intravascular space to the interstitial space can lead to edema (swelling), while fluid shifts into the alveoli in the lungs can cause pulmonary edema and impair breathing.

In a clinical setting, healthcare professionals monitor and manage fluid shifts through various strategies, such as administering intravenous fluids, using diuretics, or implementing mechanical ventilation, depending on the underlying cause and the specific effects of the fluid shift on the patient's condition.

Heart rate is the number of heartbeats per unit of time, often expressed as beats per minute (bpm). It can vary significantly depending on factors such as age, physical fitness, emotions, and overall health status. A resting heart rate between 60-100 bpm is generally considered normal for adults, but athletes and individuals with high levels of physical fitness may have a resting heart rate below 60 bpm due to their enhanced cardiovascular efficiency. Monitoring heart rate can provide valuable insights into an individual's health status, exercise intensity, and response to various treatments or interventions.

Bronchoconstrictor agents are substances that cause narrowing or constriction of the bronchioles, the small airways in the lungs. This can lead to symptoms such as wheezing, coughing, and shortness of breath. Bronchoconstrictor agents include certain medications (such as some beta-blockers and prostaglandin F2alpha), environmental pollutants (such as tobacco smoke and air pollution particles), and allergens (such as dust mites and pollen).

In contrast to bronchodilator agents, which are medications that widen the airways and improve breathing, bronchoconstrictor agents can make it more difficult for a person to breathe. People with respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD) may be particularly sensitive to bronchoconstrictor agents and may experience severe symptoms when exposed to them.

Airway obstruction is a medical condition that occurs when the normal flow of air into and out of the lungs is partially or completely blocked. This blockage can be caused by a variety of factors, including swelling of the tissues in the airway, the presence of foreign objects or substances, or abnormal growths such as tumors.

When the airway becomes obstructed, it can make it difficult for a person to breathe normally. They may experience symptoms such as shortness of breath, wheezing, coughing, and chest tightness. In severe cases, airway obstruction can lead to respiratory failure and other life-threatening complications.

There are several types of airway obstruction, including:

1. Upper airway obstruction: This occurs when the blockage is located in the upper part of the airway, such as the nose, throat, or voice box.
2. Lower airway obstruction: This occurs when the blockage is located in the lower part of the airway, such as the trachea or bronchi.
3. Partial airway obstruction: This occurs when the airway is partially blocked, allowing some air to flow in and out of the lungs.
4. Complete airway obstruction: This occurs when the airway is completely blocked, preventing any air from flowing into or out of the lungs.

Treatment for airway obstruction depends on the underlying cause of the condition. In some cases, removing the obstruction may be as simple as clearing the airway of foreign objects or mucus. In other cases, more invasive treatments such as surgery may be necessary.

Equipment design, in the medical context, refers to the process of creating and developing medical equipment and devices, such as surgical instruments, diagnostic machines, or assistive technologies. This process involves several stages, including:

1. Identifying user needs and requirements
2. Concept development and brainstorming
3. Prototyping and testing
4. Design for manufacturing and assembly
5. Safety and regulatory compliance
6. Verification and validation
7. Training and support

The goal of equipment design is to create safe, effective, and efficient medical devices that meet the needs of healthcare providers and patients while complying with relevant regulations and standards. The design process typically involves a multidisciplinary team of engineers, clinicians, designers, and researchers who work together to develop innovative solutions that improve patient care and outcomes.

A lung is a pair of spongy, elastic organs in the chest that work together to enable breathing. They are responsible for taking in oxygen and expelling carbon dioxide through the process of respiration. The left lung has two lobes, while the right lung has three lobes. The lungs are protected by the ribcage and are covered by a double-layered membrane called the pleura. The trachea divides into two bronchi, which further divide into smaller bronchioles, leading to millions of tiny air sacs called alveoli, where the exchange of gases occurs.

Posture is the position or alignment of body parts supported by the muscles, especially the spine and head in relation to the vertebral column. It can be described as static (related to a stationary position) or dynamic (related to movement). Good posture involves training your body to stand, walk, sit, and lie in positions where the least strain is placed on supporting muscles and ligaments during movement or weight-bearing activities. Poor posture can lead to various health issues such as back pain, neck pain, headaches, and respiratory problems.

The endothelium is a thin layer of simple squamous epithelial cells that lines the interior surface of blood vessels, lymphatic vessels, and heart chambers. The vascular endothelium, specifically, refers to the endothelial cells that line the blood vessels. These cells play a crucial role in maintaining vascular homeostasis by regulating vasomotor tone, coagulation, platelet activation, inflammation, and permeability of the vessel wall. They also contribute to the growth and repair of the vascular system and are involved in various pathological processes such as atherosclerosis, hypertension, and diabetes.

In medical terms, compliance refers to the degree to which a patient follows the recommendations or instructions of their healthcare provider. This may include taking prescribed medications as directed, following a treatment plan, making lifestyle changes, or attending follow-up appointments. Good compliance is essential for achieving the best possible health outcomes and can help prevent complications or worsening of medical conditions. Factors that can affect patient compliance include forgetfulness, lack of understanding of the instructions, cost of medications or treatments, and side effects of medications. Healthcare providers can take steps to improve patient compliance by providing clear and concise instructions, discussing potential barriers to compliance, and involving patients in their care plan.

Phlebography is a medical imaging technique used to visualize and assess the veins, particularly in the legs. It involves the injection of a contrast agent into the veins, followed by X-ray imaging to capture the flow of the contrast material through the veins. This allows doctors to identify any abnormalities such as blood clots, blockages, or malformations in the venous system.

There are different types of phlebography, including ascending phlebography (where the contrast agent is injected into a foot vein and travels up the leg) and descending phlebography (where the contrast agent is injected into a vein in the groin or neck and travels down the leg).

Phlebography is an invasive procedure that requires careful preparation and monitoring, and it is typically performed by radiologists or vascular specialists. It has largely been replaced by non-invasive imaging techniques such as ultrasound and CT angiography in many clinical settings.

Blood circulation, also known as cardiovascular circulation, refers to the process by which blood is pumped by the heart and circulated throughout the body through a network of blood vessels, including arteries, veins, and capillaries. This process ensures that oxygen and nutrients are delivered to cells and tissues, while waste products and carbon dioxide are removed.

The circulation of blood can be divided into two main parts: the pulmonary circulation and the systemic circulation. The pulmonary circulation involves the movement of blood between the heart and the lungs, where it picks up oxygen and releases carbon dioxide. The systemic circulation refers to the movement of blood between the heart and the rest of the body, delivering oxygen and nutrients to cells and tissues while picking up waste products for removal.

The heart plays a central role in blood circulation, acting as a pump that contracts and relaxes to move blood through the body. The contraction of the heart's left ventricle pushes oxygenated blood into the aorta, which then branches off into smaller arteries that carry blood throughout the body. The blood then flows through capillaries, where it exchanges oxygen and nutrients for waste products and carbon dioxide with surrounding cells and tissues. The deoxygenated blood is then collected in veins, which merge together to form larger vessels that eventually return the blood back to the heart's right atrium. From there, the blood is pumped into the lungs to pick up oxygen and release carbon dioxide, completing the cycle of blood circulation.

Anthropometry is the scientific study of measurements and proportions of the human body. It involves the systematic measurement and analysis of various physical characteristics, such as height, weight, blood pressure, waist circumference, and other body measurements. These measurements are used in a variety of fields, including medicine, ergonomics, forensics, and fashion design, to assess health status, fitness level, or to design products and environments that fit the human body. In a medical context, anthropometry is often used to assess growth and development, health status, and disease risk factors in individuals and populations.

In the context of traditional Chinese medicine, meridians are believed to be energy pathways or channels within the body through which Qi (vital energy) flows. There are said to be 12 main meridians and eight extra meridians that connect various organs and systems in the body. According to this belief, blockages or imbalances in the flow of Qi through these meridians can lead to illness or disease.

It's important to note that this concept of meridians is not recognized by modern Western medicine. The anatomical structures and physiological functions of meridians have not been scientifically validated, and the theories surrounding them are considered alternative or complementary medicine approaches.

Spirometry is a common type of pulmonary function test (PFT) that measures how well your lungs work. This is done by measuring how much air you can exhale from your lungs after taking a deep breath, and how quickly you can exhale it. The results are compared to normal values for your age, height, sex, and ethnicity.

Spirometry is used to diagnose and monitor certain lung conditions, such as asthma, chronic obstructive pulmonary disease (COPD), and other respiratory diseases that cause narrowing of the airways. It can also be used to assess the effectiveness of treatment for these conditions. The test is non-invasive, safe, and easy to perform.

The brachial artery is a major blood vessel in the upper arm. It supplies oxygenated blood to the muscles and tissues of the arm, forearm, and hand. The brachial artery originates from the axillary artery at the level of the shoulder joint and runs down the medial (inner) aspect of the arm, passing through the cubital fossa (the depression on the anterior side of the elbow) where it can be palpated during a routine blood pressure measurement. At the lower end of the forearm, the brachial artery bifurcates into the radial and ulnar arteries, which further divide into smaller vessels to supply the hand and fingers.

Lung compliance is a measure of the ease with which the lungs expand and is defined as the change in lung volume for a given change in transpulmonary pressure. It is often expressed in units of liters per centimeter of water (L/cm H2O). A higher compliance indicates that the lungs are more easily distensible, while a lower compliance suggests that the lungs are stiffer and require more force to expand. Lung compliance can be affected by various conditions such as pulmonary fibrosis, pneumonia, acute respiratory distress syndrome (ARDS), and chronic obstructive pulmonary disease (COPD).

The supine position is a term used in medicine to describe a body posture where an individual is lying down on their back, with their face and torso facing upwards. This position is often adopted during various medical procedures, examinations, or when resting, as it allows for easy access to the front of the body. It is also the position automatically assumed by most people who are falling asleep.

It's important to note that in the supine position, the head can be flat on the surface or raised with the use of pillows or specialized medical equipment like a hospital bed. This can help to alleviate potential issues such as breathing difficulties or swelling in the face and head.

Blood volume refers to the total amount of blood present in an individual's circulatory system at any given time. It is the combined volume of both the plasma (the liquid component of blood) and the formed elements (such as red and white blood cells and platelets) in the blood. In a healthy adult human, the average blood volume is approximately 5 liters (or about 1 gallon). However, blood volume can vary depending on several factors, including age, sex, body weight, and overall health status.

Blood volume plays a critical role in maintaining proper cardiovascular function, as it affects blood pressure, heart rate, and the delivery of oxygen and nutrients to tissues throughout the body. Changes in blood volume can have significant impacts on an individual's health and may be associated with various medical conditions, such as dehydration, hemorrhage, heart failure, and liver disease. Accurate measurement of blood volume is essential for diagnosing and managing these conditions, as well as for guiding treatment decisions in clinical settings.

Apnea is a medical condition defined as the cessation of breathing for 10 seconds or more. It can occur during sleep (sleep apnea) or while awake (wakeful apnea). There are different types of sleep apnea, including obstructive sleep apnea, central sleep apnea, and complex sleep apnea syndrome. Obstructive sleep apnea occurs when the airway becomes blocked during sleep, while central sleep apnea occurs when the brain fails to signal the muscles to breathe. Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, is a combination of obstructive and central sleep apneas. Sleep apnea can lead to various complications, such as fatigue, difficulty concentrating, high blood pressure, heart disease, and stroke.

Sensitivity and specificity are statistical measures used to describe the performance of a diagnostic test or screening tool in identifying true positive and true negative results.

* Sensitivity refers to the proportion of people who have a particular condition (true positives) who are correctly identified by the test. It is also known as the "true positive rate" or "recall." A highly sensitive test will identify most or all of the people with the condition, but may also produce more false positives.
* Specificity refers to the proportion of people who do not have a particular condition (true negatives) who are correctly identified by the test. It is also known as the "true negative rate." A highly specific test will identify most or all of the people without the condition, but may also produce more false negatives.

In medical testing, both sensitivity and specificity are important considerations when evaluating a diagnostic test. High sensitivity is desirable for screening tests that aim to identify as many cases of a condition as possible, while high specificity is desirable for confirmatory tests that aim to rule out the condition in people who do not have it.

It's worth noting that sensitivity and specificity are often influenced by factors such as the prevalence of the condition in the population being tested, the threshold used to define a positive result, and the reliability and validity of the test itself. Therefore, it's important to consider these factors when interpreting the results of a diagnostic test.

Helium is not a medical term, but it's a chemical element with symbol He and atomic number 2. It's a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gases section of the periodic table. In medicine, helium is sometimes used in medical settings for its unique properties, such as being less dense than air, which can help improve the delivery of oxygen to patients with respiratory conditions. For example, heliox, a mixture of helium and oxygen, may be used to reduce the work of breathing in patients with conditions like chronic obstructive pulmonary disease (COPD) or asthma. Additionally, helium is also used in cryogenic medical equipment and in magnetic resonance imaging (MRI) machines to cool the superconducting magnets.

Inhalation is the act or process of breathing in where air or other gases are drawn into the lungs. It's also known as inspiration. This process involves several muscles, including the diaphragm and intercostal muscles between the ribs, working together to expand the chest cavity and decrease the pressure within the thorax, which then causes air to flow into the lungs.

In a medical context, inhalation can also refer to the administration of medications or therapeutic gases through the respiratory tract, typically using an inhaler or nebulizer. This route of administration allows for direct delivery of the medication to the lungs, where it can be quickly absorbed into the bloodstream and exert its effects.

Vasoconstriction is a medical term that refers to the narrowing of blood vessels due to the contraction of the smooth muscle in their walls. This process decreases the diameter of the lumen (the inner space of the blood vessel) and reduces blood flow through the affected vessels. Vasoconstriction can occur throughout the body, but it is most noticeable in the arterioles and precapillary sphincters, which control the amount of blood that flows into the capillary network.

The autonomic nervous system, specifically the sympathetic division, plays a significant role in regulating vasoconstriction through the release of neurotransmitters like norepinephrine (noradrenaline). Various hormones and chemical mediators, such as angiotensin II, endothelin-1, and serotonin, can also induce vasoconstriction.

Vasoconstriction is a vital physiological response that helps maintain blood pressure and regulate blood flow distribution in the body. However, excessive or prolonged vasoconstriction may contribute to several pathological conditions, including hypertension, stroke, and peripheral vascular diseases.

Reference values, also known as reference ranges or reference intervals, are the set of values that are considered normal or typical for a particular population or group of people. These values are often used in laboratory tests to help interpret test results and determine whether a patient's value falls within the expected range.

The process of establishing reference values typically involves measuring a particular biomarker or parameter in a large, healthy population and then calculating the mean and standard deviation of the measurements. Based on these statistics, a range is established that includes a certain percentage of the population (often 95%) and excludes extreme outliers.

It's important to note that reference values can vary depending on factors such as age, sex, race, and other demographic characteristics. Therefore, it's essential to use reference values that are specific to the relevant population when interpreting laboratory test results. Additionally, reference values may change over time due to advances in measurement technology or changes in the population being studied.

Lower Body Negative Pressure (LBNP) is a medical term that refers to the application of a negative pressure (below atmospheric pressure) to the lower body, while the upper body remains at normal atmospheric pressure. This is typically achieved through the use of an air-tight chamber or suit that covers the lower body from the waist down.

The negative pressure causes fluid to be drawn towards the lower body, which can simulate the effects of weightlessness or reduced gravity on the cardiovascular system. LBNP is often used in research settings to study the physiological responses to changes in gravitational forces, as well as in clinical settings to help prevent or treat various medical conditions, such as orthostatic intolerance, venous ulcers, and chronic wounds.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick, muscular walls that can withstand the high pressure of blood being pumped out of the heart. Arteries branch off into smaller vessels called arterioles, which further divide into a vast network of tiny capillaries where the exchange of oxygen, nutrients, and waste occurs between the blood and the body's cells. After passing through the capillary network, deoxygenated blood collects in venules, then merges into veins, which return the blood back to the heart.

Indicator dilution techniques are a group of methods used in medicine and research to measure various physiological variables, such as cardiac output or cerebral blood flow. These techniques involve introducing a known quantity of an indicator substance (like a dye or a radioactive tracer) into the system being studied and then measuring its concentration over time at a specific location downstream.

The basic principle behind these techniques is that the concentration of the indicator substance will be inversely proportional to the flow rate of the fluid through which it is moving. By measuring the concentration of the indicator substance at different points in time, researchers can calculate the flow rate using mathematical formulas.

Indicator dilution techniques are widely used in clinical and research settings because they are relatively non-invasive and can provide accurate and reliable measurements of various physiological variables. Some common examples of indicator dilution techniques include thermodilution, dye dilution, and Fick principle-based methods.

In medical terms, 'air' is defined as the mixture of gases that make up the Earth's atmosphere. It primarily consists of nitrogen (78%), oxygen (21%), and small amounts of other gases such as argon, carbon dioxide, and trace amounts of neon, helium, and methane.

Air is essential for human life, as it provides the oxygen that our bodies need to produce energy through respiration. We inhale air into our lungs, where oxygen is absorbed into the bloodstream and transported to cells throughout the body. At the same time, carbon dioxide, a waste product of cellular metabolism, is exhaled out of the body through the lungs and back into the atmosphere.

In addition to its role in respiration, air also plays a critical role in regulating the Earth's climate and weather patterns, as well as serving as a medium for sound waves and other forms of energy transfer.

In medical terms, pressure is defined as the force applied per unit area on an object or body surface. It is often measured in millimeters of mercury (mmHg) in clinical settings. For example, blood pressure is the force exerted by circulating blood on the walls of the arteries and is recorded as two numbers: systolic pressure (when the heart beats and pushes blood out) and diastolic pressure (when the heart rests between beats).

Pressure can also refer to the pressure exerted on a wound or incision to help control bleeding, or the pressure inside the skull or spinal canal. High or low pressure in different body systems can indicate various medical conditions and require appropriate treatment.

The popliteal vein is the continuation of the tibial and fibular (or anterior and posterior tibial) veins, forming in the lower leg's back portion or popliteal fossa. It carries blood from the leg towards the heart. The popliteal vein is located deep within the body and is accompanied by the popliteal artery, which supplies oxygenated blood to the lower leg. This venous structure is a crucial part of the venous system in the lower extremities and is often assessed during physical examinations for signs of venous insufficiency or deep vein thrombosis (DVT).

Residual Volume (RV) is the amount of air that remains in the lungs after a forced exhale, also known as the "expiratory reserve volume." It is the lowest lung volume that can be reached during a forced exhalation and cannot be completely emptied due to the presence of alveoli that are too small or too far from the airways. This volume is important for maintaining the structural integrity of the lungs and preventing their collapse. Any additional air that enters the lungs after this point will increase the total lung capacity. The normal residual volume for an average adult human is typically around 1 to 1.5 liters.

A cross-over study is a type of experimental design in which participants receive two or more interventions in a specific order. After a washout period, each participant receives the opposite intervention(s). The primary advantage of this design is that it controls for individual variability by allowing each participant to act as their own control.

In medical research, cross-over studies are often used to compare the efficacy or safety of two treatments. For example, a researcher might conduct a cross-over study to compare the effectiveness of two different medications for treating high blood pressure. Half of the participants would be randomly assigned to receive one medication first and then switch to the other medication after a washout period. The other half of the participants would receive the opposite order of treatments.

Cross-over studies can provide valuable insights into the relative merits of different interventions, but they also have some limitations. For example, they may not be suitable for studying conditions that are chronic or irreversible, as it may not be possible to completely reverse the effects of the first intervention before administering the second one. Additionally, carryover effects from the first intervention can confound the results if they persist into the second treatment period.

Overall, cross-over studies are a useful tool in medical research when used appropriately and with careful consideration of their limitations.

Analysis of Variance (ANOVA) is a statistical technique used to compare the means of two or more groups and determine whether there are any significant differences between them. It is a way to analyze the variance in a dataset to determine whether the variability between groups is greater than the variability within groups, which can indicate that the groups are significantly different from one another.

ANOVA is based on the concept of partitioning the total variance in a dataset into two components: variance due to differences between group means (also known as "between-group variance") and variance due to differences within each group (also known as "within-group variance"). By comparing these two sources of variance, ANOVA can help researchers determine whether any observed differences between groups are statistically significant, or whether they could have occurred by chance.

ANOVA is a widely used technique in many areas of research, including biology, psychology, engineering, and business. It is often used to compare the means of two or more experimental groups, such as a treatment group and a control group, to determine whether the treatment had a significant effect. ANOVA can also be used to compare the means of different populations or subgroups within a population, to identify any differences that may exist between them.

Cardiac output is a measure of the amount of blood that is pumped by the heart in one minute. It is defined as the product of stroke volume (the amount of blood pumped by the left ventricle during each contraction) and heart rate (the number of contractions per minute). Normal cardiac output at rest for an average-sized adult is about 5 to 6 liters per minute. Cardiac output can be increased during exercise or other conditions that require more blood flow, such as during illness or injury. It can be measured noninvasively using techniques such as echocardiography or invasively through a catheter placed in the heart.

Electric conductivity, also known as electrical conductance, is a measure of a material's ability to allow the flow of electric current through it. It is usually measured in units of Siemens per meter (S/m) or ohm-meters (Ω-m).

In medical terms, electric conductivity can refer to the body's ability to conduct electrical signals, which is important for various physiological processes such as nerve impulse transmission and muscle contraction. Abnormalities in electrical conductivity can be associated with various medical conditions, including neurological disorders and heart diseases.

For example, in electrocardiography (ECG), the electric conductivity of the heart is measured to assess its electrical activity and identify any abnormalities that may indicate heart disease. Similarly, in electromyography (EMG), the electric conductivity of muscles is measured to diagnose neuromuscular disorders.

In medical terms, the arm refers to the upper limb of the human body, extending from the shoulder to the wrist. It is composed of three major bones: the humerus in the upper arm, and the radius and ulna in the lower arm. The arm contains several joints, including the shoulder joint, elbow joint, and wrist joint, which allow for a wide range of motion. The arm also contains muscles, blood vessels, nerves, and other soft tissues that are essential for normal function.

Respiratory rate is the number of breaths a person takes per minute. It is typically measured by counting the number of times the chest rises and falls in one minute. Normal respiratory rate at rest for an adult ranges from 12 to 20 breaths per minute. An increased respiratory rate (tachypnea) or decreased respiratory rate (bradypnea) can be a sign of various medical conditions, such as lung disease, heart failure, or neurological disorders. It is an important vital sign that should be regularly monitored in clinical settings.

Nitroglycerin, also known as glyceryl trinitrate, is a medication used primarily for the treatment of angina pectoris (chest pain due to coronary artery disease) and hypertensive emergencies (severe high blood pressure). It belongs to a class of drugs called nitrates or organic nitrites.

Nitroglycerin works by relaxing and dilating the smooth muscle in blood vessels, which leads to decreased workload on the heart and increased oxygen delivery to the myocardium (heart muscle). This results in reduced symptoms of angina and improved cardiac function during hypertensive emergencies.

The drug is available in various forms, including sublingual tablets, sprays, transdermal patches, ointments, and intravenous solutions. The choice of formulation depends on the specific clinical situation and patient needs. Common side effects of nitroglycerin include headache, dizziness, and hypotension (low blood pressure).

Bronchoconstriction is a medical term that refers to the narrowing of the airways in the lungs (the bronchi and bronchioles) due to the contraction of the smooth muscles surrounding them. This constriction can cause difficulty breathing, wheezing, coughing, and shortness of breath, which are common symptoms of asthma and other respiratory conditions.

Bronchoconstriction can be triggered by a variety of factors, including allergens, irritants, cold air, exercise, and emotional stress. In some cases, it may also be caused by certain medications, such as beta-blockers or nonsteroidal anti-inflammatory drugs (NSAIDs). Treatment for bronchoconstriction typically involves the use of bronchodilators, which are medications that help to relax the smooth muscles around the airways and widen them, making it easier to breathe.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

A tilt-table test is a diagnostic procedure used to evaluate symptoms of syncope (fainting) or near-syncope. It measures your body's cardiovascular response to changes in position. During the test, you lie on a table that can be tilted to change the angle of your body from horizontal to upright. This simulates what happens when you stand up from a lying down position.

The test monitors heart rate, blood pressure, and oxygen levels while you're in different positions. If you experience symptoms like dizziness or fainting during the test, these can provide clues about the cause of your symptoms. The test is used to diagnose conditions like orthostatic hypotension (a sudden drop in blood pressure when standing), vasovagal syncope (fainting due to an overactive vagus nerve), and other heart rhythm disorders.

Respiratory muscles are a group of muscles involved in the process of breathing. They include the diaphragm, intercostal muscles (located between the ribs), scalene muscles (located in the neck), and abdominal muscles. These muscles work together to allow the chest cavity to expand or contract, which draws air into or pushes it out of the lungs. The diaphragm is the primary muscle responsible for breathing, contracting to increase the volume of the chest cavity and draw air into the lungs during inhalation. The intercostal muscles help to further expand the ribcage, while the abdominal muscles assist in exhaling by compressing the abdomen and pushing up on the diaphragm.

"Gravity suits" is not a recognized medical term. However, in the context of space medicine and space travel, gravity suits, also known as g-suits or anti-G suits, are specialized garments worn by pilots and astronauts to prevent or reduce the negative effects of high gravitational forces (G-forces) on their bodies during high-speed maneuvers or while re-entering the Earth's atmosphere.

These suits work by applying pressure to specific areas of the body, typically around the lower abdomen and legs, to prevent the pooling of blood in those areas due to the increased G-forces. This helps maintain adequate blood flow to the brain and other vital organs, reducing the risk of loss of consciousness (G-induced Loss of Consciousness or G-LOC) and other symptoms associated with high G-forces such as blackouts, vision impairment, and disorientation.

It's important to note that gravity suits are not used as a medical treatment for any specific condition but rather as a protective measure during space travel and high-performance aviation.

Esophageal pH monitoring is a medical test used to measure the acidity (pH level) inside the esophagus. The test involves inserting a thin, flexible tube through the nose and down into the esophagus. The tube contains a sensor that detects changes in pH levels and transmits this information to a recording device worn by the patient.

The test typically lasts for 24 hours, during which time the patient keeps a diary of their activities and symptoms. This information is used to correlate any symptoms with changes in pH levels. The test can help diagnose gastroesophageal reflux disease (GERD) and assess the effectiveness of treatment.

It's important to note that there are some precautions to be taken before and after the test, such as avoiding certain medications that may affect the pH levels or interfere with the test results. Patients should follow their healthcare provider's instructions carefully to ensure accurate results.

The femoral vein is the large vein that runs through the thigh and carries oxygen-depleted blood from the lower limbs back to the heart. It is located in the femoral triangle, along with the femoral artery and nerve. The femoral vein begins at the knee as the popliteal vein, which then joins with the deep vein of the thigh to form the femoral vein. As it moves up the leg, it is joined by several other veins, including the great saphenous vein, before it becomes the external iliac vein at the inguinal ligament in the groin.

Equipment Failure Analysis is a process of identifying the cause of failure in medical equipment or devices. This involves a systematic examination and evaluation of the equipment, its components, and operational history to determine why it failed. The analysis may include physical inspection, chemical testing, and review of maintenance records, as well as assessment of design, manufacturing, and usage factors that may have contributed to the failure.

The goal of Equipment Failure Analysis is to identify the root cause of the failure, so that corrective actions can be taken to prevent similar failures in the future. This is important in medical settings to ensure patient safety and maintain the reliability and effectiveness of medical equipment.

The vasomotor system is a part of the autonomic nervous system that controls the diameter of blood vessels, particularly the smooth muscle in the walls of arterioles and precapillary sphincters. It regulates blood flow to different parts of the body by constricting or dilating these vessels. The vasomotor center located in the medulla oblongata of the brainstem controls the system, receiving input from various sensory receptors and modulating the sympathetic and parasympathetic nervous systems' activity. Vasoconstriction decreases blood flow, while vasodilation increases it.

Hypercapnia is a state of increased carbon dioxide (CO2) concentration in the blood, typically defined as an arterial CO2 tension (PaCO2) above 45 mmHg. It is often associated with conditions that impair gas exchange or eliminate CO2 from the body, such as chronic obstructive pulmonary disease (COPD), severe asthma, respiratory failure, or certain neuromuscular disorders. Hypercapnia can cause symptoms such as headache, confusion, shortness of breath, and in severe cases, it can lead to life-threatening complications such as respiratory acidosis, coma, and even death if not promptly treated.

Raynaud's disease, also known as Raynaud's phenomenon or syndrome, is a condition that affects the blood vessels, particularly in the fingers and toes. It is characterized by episodes of vasospasm (constriction) of the small digital arteries and arterioles, which can be triggered by cold temperatures or emotional stress. This results in reduced blood flow to the affected areas, causing them to become pale or white and then cyanotic (blue) due to the accumulation of deoxygenated blood. As the episode resolves, the affected areas may turn red as blood flow returns, sometimes accompanied by pain, numbness, or tingling sensations.

Raynaud's disease can be primary, meaning it occurs without an underlying medical condition, or secondary, which is associated with connective tissue disorders, autoimmune diseases, or other health issues such as carpal tunnel syndrome, vibration tool usage, or smoking. Primary Raynaud's is more common and tends to be less severe than secondary Raynaud's.

Treatment for Raynaud's disease typically involves avoiding triggers, keeping the body warm, and using medications to help dilate blood vessels and improve circulation. In some cases, lifestyle modifications and smoking cessation may also be recommended to manage symptoms and prevent progression of the condition.

Forced Expiratory Volume (FEV) is a medical term used to describe the volume of air that can be forcefully exhaled from the lungs in one second. It is often measured during pulmonary function testing to assess lung function and diagnose conditions such as chronic obstructive pulmonary disease (COPD) or asthma.

FEV is typically expressed as a percentage of the Forced Vital Capacity (FVC), which is the total volume of air that can be exhaled from the lungs after taking a deep breath in. The ratio of FEV to FVC is used to determine whether there is obstruction in the airways, with a lower ratio indicating more severe obstruction.

There are different types of FEV measurements, including FEV1 (the volume of air exhaled in one second), FEV25-75 (the average volume of air exhaled during the middle 50% of the FVC maneuver), and FEV0.5 (the volume of air exhaled in half a second). These measurements can provide additional information about lung function and help guide treatment decisions.

Manometry is a medical test that measures pressure inside various parts of the gastrointestinal tract. It is often used to help diagnose digestive disorders such as achalasia, gastroparesis, and irritable bowel syndrome. During the test, a thin, flexible tube called a manometer is inserted through the mouth or rectum and into the area being tested. The tube is connected to a machine that measures and records pressure readings. These readings can help doctors identify any abnormalities in muscle function or nerve reflexes within the digestive tract.

Vasoconstrictor agents are substances that cause the narrowing of blood vessels by constricting the smooth muscle in their walls. This leads to an increase in blood pressure and a decrease in blood flow. They work by activating the sympathetic nervous system, which triggers the release of neurotransmitters such as norepinephrine and epinephrine that bind to alpha-adrenergic receptors on the smooth muscle cells of the blood vessel walls, causing them to contract.

Vasoconstrictor agents are used medically for a variety of purposes, including:

* Treating hypotension (low blood pressure)
* Controlling bleeding during surgery or childbirth
* Relieving symptoms of nasal congestion in conditions such as the common cold or allergies

Examples of vasoconstrictor agents include phenylephrine, oxymetazoline, and epinephrine. It's important to note that prolonged use or excessive doses of vasoconstrictor agents can lead to rebound congestion and other adverse effects, so they should be used with caution and under the guidance of a healthcare professional.

Nitric oxide (NO) is a molecule made up of one nitrogen atom and one oxygen atom. In the body, it is a crucial signaling molecule involved in various physiological processes such as vasodilation, immune response, neurotransmission, and inhibition of platelet aggregation. It is produced naturally by the enzyme nitric oxide synthase (NOS) from the amino acid L-arginine. Inhaled nitric oxide is used medically to treat pulmonary hypertension in newborns and adults, as it helps to relax and widen blood vessels, improving oxygenation and blood flow.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Skin temperature is the measure of heat emitted by the skin, which can be an indicator of the body's core temperature. It is typically lower than the body's internal temperature and varies depending on factors such as environmental temperature, blood flow, and physical activity. Skin temperature is often used as a vital sign in medical settings and can be measured using various methods, including thermal scanners, digital thermometers, or mercury thermometers. Changes in skin temperature may also be associated with certain medical conditions, such as inflammation, infection, or nerve damage.

Anoxia is a medical condition that refers to the absence or complete lack of oxygen supply in the body or a specific organ, tissue, or cell. This can lead to serious health consequences, including damage or death of cells and tissues, due to the vital role that oxygen plays in supporting cellular metabolism and energy production.

Anoxia can occur due to various reasons, such as respiratory failure, cardiac arrest, severe blood loss, carbon monoxide poisoning, or high altitude exposure. Prolonged anoxia can result in hypoxic-ischemic encephalopathy, a serious condition that can cause brain damage and long-term neurological impairments.

Medical professionals use various diagnostic tests, such as blood gas analysis, pulse oximetry, and electroencephalography (EEG), to assess oxygen levels in the body and diagnose anoxia. Treatment for anoxia typically involves addressing the underlying cause, providing supplemental oxygen, and supporting vital functions, such as breathing and circulation, to prevent further damage.

The abdomen refers to the portion of the body that lies between the thorax (chest) and the pelvis. It is a musculo-fascial cavity containing the digestive, urinary, and reproductive organs. The abdominal cavity is divided into several regions and quadrants for medical description and examination purposes. These include the upper and lower abdomen, as well as nine quadrants formed by the intersection of the midline and a horizontal line drawn at the level of the umbilicus (navel).

The major organs located within the abdominal cavity include:

1. Stomach - muscular organ responsible for initial digestion of food
2. Small intestine - long, coiled tube where most nutrient absorption occurs
3. Large intestine - consists of the colon and rectum; absorbs water and stores waste products
4. Liver - largest internal organ, involved in protein synthesis, detoxification, and metabolism
5. Pancreas - secretes digestive enzymes and hormones such as insulin
6. Spleen - filters blood and removes old red blood cells
7. Kidneys - pair of organs responsible for filtering waste products from the blood and producing urine
8. Adrenal glands - sit atop each kidney, produce hormones that regulate metabolism, immune response, and stress response

The abdomen is an essential part of the human body, playing a crucial role in digestion, absorption, and elimination of food and waste materials, as well as various metabolic processes.

The double-blind method is a study design commonly used in research, including clinical trials, to minimize bias and ensure the objectivity of results. In this approach, both the participants and the researchers are unaware of which group the participants are assigned to, whether it be the experimental group or the control group. This means that neither the participants nor the researchers know who is receiving a particular treatment or placebo, thus reducing the potential for bias in the evaluation of outcomes. The assignment of participants to groups is typically done by a third party not involved in the study, and the codes are only revealed after all data have been collected and analyzed.

Varicose veins are defined as enlarged, swollen, and twisting veins often appearing blue or dark purple, which usually occur in the legs. They are caused by weakened valves and vein walls that can't effectively push blood back toward the heart. This results in a buildup of blood, causing the veins to bulge and become varicose.

The condition is generally harmless but may cause symptoms like aching, burning, muscle cramp, or a feeling of heaviness in the legs. In some cases, varicose veins can lead to more serious problems, such as skin ulcers, blood clots, or chronic venous insufficiency. Treatment options include lifestyle changes, compression stockings, and medical procedures like sclerotherapy, laser surgery, or endovenous ablation.

Adipose tissue, also known as fatty tissue, is a type of connective tissue that is composed mainly of adipocytes (fat cells). It is found throughout the body, but is particularly abundant in the abdominal cavity, beneath the skin, and around organs such as the heart and kidneys.

Adipose tissue serves several important functions in the body. One of its primary roles is to store energy in the form of fat, which can be mobilized and used as an energy source during periods of fasting or exercise. Adipose tissue also provides insulation and cushioning for the body, and produces hormones that help regulate metabolism, appetite, and reproductive function.

There are two main types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). WAT is the more common form and is responsible for storing energy as fat. BAT, on the other hand, contains a higher number of mitochondria and is involved in heat production and energy expenditure.

Excessive accumulation of adipose tissue can lead to obesity, which is associated with an increased risk of various health problems such as diabetes, heart disease, and certain types of cancer.

Forced expiratory flow rates (FEFR) are measures of how quickly and efficiently air can be exhaled from the lungs during a forced breath maneuver. These measurements are often used in pulmonary function testing to help diagnose and monitor obstructive lung diseases such as asthma or chronic obstructive pulmonary disease (COPD).

FEFR is typically measured during a forced expiratory maneuver, where the person takes a deep breath in and then exhales as forcefully and quickly as possible into a mouthpiece connected to a spirometer. The spirometer measures the volume and flow rate of the exhaled air over time.

There are several different FEFR measurements that can be reported, including:

* Forced Expiratory Flow (FEF) 25-75%: This is the average flow rate during the middle half of the forced expiratory maneuver.
* Peak Expiratory Flow Rate (PEFR): This is the maximum flow rate achieved during the first second of the forced expiratory maneuver.
* Forced Expiratory Volume in 1 Second (FEV1): This is the volume of air exhaled in the first second of the forced expiratory maneuver.

Abnormal FEFR values can indicate obstruction in the small airways of the lungs, which can make it difficult to breathe out fully and quickly. The specific pattern of abnormalities in FEFR measurements can help doctors differentiate between different types of obstructive lung diseases.

In medical terms, fingers are not specifically defined as they are common anatomical structures. However, I can provide you with a general anatomy definition:

Fingers are the terminal parts of the upper limb in primates, including humans, consisting of four digits (thumb, index, middle, and ring fingers) and one opposable thumb. They contain bones called phalanges, connected by joints that allow for movement and flexibility. Each finger has a nail, nerve endings for sensation, and blood vessels to supply nutrients and oxygen. Fingers are crucial for various activities such as grasping, manipulating objects, and tactile exploration of the environment.

The Predictive Value of Tests, specifically the Positive Predictive Value (PPV) and Negative Predictive Value (NPV), are measures used in diagnostic tests to determine the probability that a positive or negative test result is correct.

Positive Predictive Value (PPV) is the proportion of patients with a positive test result who actually have the disease. It is calculated as the number of true positives divided by the total number of positive results (true positives + false positives). A higher PPV indicates that a positive test result is more likely to be a true positive, and therefore the disease is more likely to be present.

Negative Predictive Value (NPV) is the proportion of patients with a negative test result who do not have the disease. It is calculated as the number of true negatives divided by the total number of negative results (true negatives + false negatives). A higher NPV indicates that a negative test result is more likely to be a true negative, and therefore the disease is less likely to be present.

The predictive value of tests depends on the prevalence of the disease in the population being tested, as well as the sensitivity and specificity of the test. A test with high sensitivity and specificity will generally have higher predictive values than a test with low sensitivity and specificity. However, even a highly sensitive and specific test can have low predictive values if the prevalence of the disease is low in the population being tested.

Exercise is defined in the medical context as a physical activity that is planned, structured, and repetitive, with the primary aim of improving or maintaining one or more components of physical fitness. Components of physical fitness include cardiorespiratory endurance, muscular strength, muscular endurance, flexibility, and body composition. Exercise can be classified based on its intensity (light, moderate, or vigorous), duration (length of time), and frequency (number of times per week). Common types of exercise include aerobic exercises, such as walking, jogging, cycling, and swimming; resistance exercises, such as weightlifting; flexibility exercises, such as stretching; and balance exercises. Exercise has numerous health benefits, including reducing the risk of chronic diseases, improving mental health, and enhancing overall quality of life.

Central venous pressure (CVP) is the blood pressure measured in the large veins that enter the right atrium of the heart. It reflects the amount of blood returning to the heart and the ability of the heart to pump it effectively. CVP is used as an indicator of a person's intravascular volume status, cardiac function, and overall hemodynamic performance. The measurement is taken using a central venous catheter placed in a large vein such as the internal jugular or subclavian vein. Normal CVP values range from 0 to 8 mmHg (millimeters of mercury) in adults when measured at the level of the right atrium.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

A varicose ulcer is a type of chronic wound that typically occurs on the lower leg, often as a result of poor circulation and venous insufficiency. These ulcers form when there is increased pressure in the veins, leading to damage and leakage of fluids into the surrounding tissues. Over time, this can cause the skin to break down and form an open sore or ulcer.

Varicose ulcers are often associated with varicose veins, which are swollen and twisted veins that are visible just beneath the surface of the skin. These veins have weakened walls and valves, which can lead to the pooling of blood and fluid in the lower legs. This increased pressure can cause damage to the surrounding tissues, leading to the formation of an ulcer.

Varicose ulcers are typically slow to heal and may require extensive treatment, including compression therapy, wound care, and sometimes surgery. Risk factors for developing varicose ulcers include obesity, smoking, sedentary lifestyle, and a history of deep vein thrombosis or other circulatory problems.

Conductometry is a method used to measure the electrical conductivity of a solution, which can change in the presence of certain ions or chemical reactions. In conductometry, a conductivity probe or electrode is placed in the solution and an electrical current is passed through it. The resistance of the solution is then measured and converted into a measurement of conductivity.

Conductometry is often used to monitor chemical reactions that produce or consume ions, such as acid-base titrations, oxidation-reduction reactions, and complexation reactions. By measuring changes in conductivity over time, researchers can gain insights into the rate and extent of these reactions.

In medical research, conductometry may be used to study the electrical properties of biological tissues, such as skin or blood, or to monitor chemical processes in the body, such as the metabolism of drugs or other substances. However, it is not a commonly used diagnostic tool in clinical medicine.

The term "extremities" in a medical context refers to the most distant parts of the body, including the hands and feet (both fingers and toes), as well as the arms and legs. These are the farthest parts from the torso and head. Medical professionals may examine a patient's extremities for various reasons, such as checking circulation, assessing nerve function, or looking for injuries or abnormalities.

Hypertension is a medical term used to describe abnormally high blood pressure in the arteries, often defined as consistently having systolic blood pressure (the top number in a blood pressure reading) over 130 mmHg and/or diastolic blood pressure (the bottom number) over 80 mmHg. It is also commonly referred to as high blood pressure.

Hypertension can be classified into two types: primary or essential hypertension, which has no identifiable cause and accounts for about 95% of cases, and secondary hypertension, which is caused by underlying medical conditions such as kidney disease, hormonal disorders, or use of certain medications.

If left untreated, hypertension can lead to serious health complications such as heart attack, stroke, heart failure, and chronic kidney disease. Therefore, it is important for individuals with hypertension to manage their condition through lifestyle modifications (such as healthy diet, regular exercise, stress management) and medication if necessary, under the guidance of a healthcare professional.

I'm sorry for any confusion, but "Linear Models" is actually a term from the field of statistics and machine learning, rather than medicine. A linear model is a type of statistical model that is used to analyze the relationship between two or more variables. In a linear model, the relationship between the dependent variable (the outcome or result) and the independent variable(s) (the factors being studied) is assumed to be linear, meaning that it can be described by a straight line on a graph.

The equation for a simple linear model with one independent variable (x) and one dependent variable (y) looks like this:

y = β0 + β1*x + ε

In this equation, β0 is the y-intercept or the value of y when x equals zero, β1 is the slope or the change in y for each unit increase in x, and ε is the error term or the difference between the actual values of y and the predicted values of y based on the linear model.

Linear models are widely used in medical research to study the relationship between various factors (such as exposure to a risk factor or treatment) and health outcomes (such as disease incidence or mortality). They can also be used to adjust for confounding variables, which are factors that may influence both the independent variable and the dependent variable, and thus affect the observed relationship between them.

"Medical electronics" refers to the field of electronics that is specifically designed for medical applications. This can include a wide range of devices and systems, such as:

1. Medical imaging equipment, such as X-ray machines, CT scanners, MRI machines, and ultrasound machines.
2. Patient monitoring equipment, such as heart rate monitors, blood pressure monitors, and oxygen saturation monitors.
3. Therapeutic devices, such as pacemakers, defibrillators, and deep brain stimulators.
4. Laboratory equipment, such as DNA sequencers, mass spectrometers, and microarray scanners.
5. Wearable health technology, such as fitness trackers, smartwatches, and continuous glucose monitors.
6. Telemedicine systems that enable remote consultations and patient monitoring.

Medical electronics must meet strict regulatory requirements to ensure safety, effectiveness, and reliability. These devices often require specialized electronic components, such as sensors, signal processing circuits, and power management circuits, that are designed to operate in the challenging environments found in medical settings. Medical electronics engineers must have a deep understanding of both electronics and medical applications to design and develop these complex systems.

Vital capacity (VC) is a term used in pulmonary function tests to describe the maximum volume of air that can be exhaled after taking a deep breath. It is the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. In other words, it's the total amount of air you can forcibly exhale after inhaling as deeply as possible. Vital capacity is an important measurement in assessing lung function and can be reduced in conditions such as chronic obstructive pulmonary disease (COPD), asthma, and other respiratory disorders.

Bronchial provocation tests are a group of medical tests used to assess the airway responsiveness of the lungs by challenging them with increasing doses of a specific stimulus, such as methacholine or histamine, which can cause bronchoconstriction (narrowing of the airways) in susceptible individuals. These tests are often performed to diagnose and monitor asthma and other respiratory conditions that may be associated with heightened airway responsiveness.

The most common type of bronchial provocation test is the methacholine challenge test, which involves inhaling increasing concentrations of methacholine aerosol via a nebulizer. The dose response is measured by monitoring lung function (usually through spirometry) before and after each exposure. A positive test is indicated when there is a significant decrease in forced expiratory volume in one second (FEV1) or other measures of airflow, which suggests bronchial hyperresponsiveness.

Other types of bronchial provocation tests include histamine challenges, exercise challenges, and mannitol challenges. These tests have specific indications, contraindications, and protocols that should be followed to ensure accurate results and patient safety. Bronchial provocation tests are typically conducted in a controlled clinical setting under the supervision of trained healthcare professionals.

The sympathetic nervous system (SNS) is a part of the autonomic nervous system that operates largely below the level of consciousness, and it functions to produce appropriate physiological responses to perceived danger. It's often associated with the "fight or flight" response. The SNS uses nerve impulses to stimulate target organs, causing them to speed up (e.g., increased heart rate), prepare for action, or otherwise respond to stressful situations.

The sympathetic nervous system is activated due to stressful emotional or physical situations and it prepares the body for immediate actions. It dilates the pupils, increases heart rate and blood pressure, accelerates breathing, and slows down digestion. The primary neurotransmitter involved in this system is norepinephrine (also known as noradrenaline).

Bronchodilators are medications that relax and widen the airways (bronchioles) in the lungs, making it easier to breathe. They work by relaxing the smooth muscle around the airways, which allows them to dilate or open up. This results in improved airflow and reduced symptoms of bronchoconstriction, such as wheezing, coughing, and shortness of breath.

Bronchodilators can be classified into two main types: short-acting and long-acting. Short-acting bronchodilators are used for quick relief of symptoms and last for 4 to 6 hours, while long-acting bronchodilators are used for maintenance therapy and provide symptom relief for 12 hours or more.

Examples of bronchodilator agents include:

* Short-acting beta-agonists (SABAs) such as albuterol, levalbuterol, and pirbuterol
* Long-acting beta-agonists (LABAs) such as salmeterol, formoterol, and indacaterol
* Anticholinergics such as ipratropium, tiotropium, and aclidinium
* Combination bronchodilators that contain both a LABA and an anticholinergic, such as umeclidinium/vilanterol and glycopyrrolate/formoterol.

Intra-arterial injection is a type of medical procedure where a medication or contrast agent is delivered directly into an artery. This technique is used for various therapeutic and diagnostic purposes.

For instance, intra-arterial chemotherapy may be used to deliver cancer drugs directly to the site of a tumor, while intra-arterial thrombolysis involves the administration of clot-busting medications to treat arterial blockages caused by blood clots. Intra-arterial injections are also used in diagnostic imaging procedures such as angiography, where a contrast agent is injected into an artery to visualize the blood vessels and identify any abnormalities.

It's important to note that intra-arterial injections require precise placement of the needle or catheter into the artery, and are typically performed by trained medical professionals using specialized equipment.

Computer-assisted diagnosis (CAD) is the use of computer systems to aid in the diagnostic process. It involves the use of advanced algorithms and data analysis techniques to analyze medical images, laboratory results, and other patient data to help healthcare professionals make more accurate and timely diagnoses. CAD systems can help identify patterns and anomalies that may be difficult for humans to detect, and they can provide second opinions and flag potential errors or uncertainties in the diagnostic process.

CAD systems are often used in conjunction with traditional diagnostic methods, such as physical examinations and patient interviews, to provide a more comprehensive assessment of a patient's health. They are commonly used in radiology, pathology, cardiology, and other medical specialties where imaging or laboratory tests play a key role in the diagnostic process.

While CAD systems can be very helpful in the diagnostic process, they are not infallible and should always be used as a tool to support, rather than replace, the expertise of trained healthcare professionals. It's important for medical professionals to use their clinical judgment and experience when interpreting CAD results and making final diagnoses.

Photoplethysmography (PPG) is a non-invasive method used to measure changes in blood volume in the microvascular bed of tissue, typically the skin. It is based on the principle that light absorption and reflection by the skin change as the amount of blood in the capillaries changes due to the cardiac cycle.

A PPG sensor consists of a light-emitting diode (LED) that emits light at a specific wavelength, typically red or infrared, and a photodiode detector that measures the intensity of the transmitted or reflected light. The LED is placed in contact with the skin, and as the blood volume in the capillaries changes during the cardiac cycle, the amount of light absorbed or reflected by the skin also changes.

The PPG signal provides information about the cardiovascular system, including heart rate, blood pressure, and peripheral vascular tone. It is widely used in medical devices such as pulse oximeters, which measure oxygen saturation in the blood, and wearable devices for monitoring vital signs.

Biosensing techniques refer to the methods and technologies used to detect and measure biological molecules or processes, typically through the use of a physical device or sensor. These techniques often involve the conversion of a biological response into an electrical signal that can be measured and analyzed. Examples of biosensing techniques include electrochemical biosensors, optical biosensors, and piezoelectric biosensors.

Electrochemical biosensors measure the electrical current or potential generated by a biochemical reaction at an electrode surface. This type of biosensor typically consists of a biological recognition element, such as an enzyme or antibody, that is immobilized on the electrode surface and interacts with the target analyte to produce an electrical signal.

Optical biosensors measure changes in light intensity or wavelength that occur when a biochemical reaction takes place. This type of biosensor can be based on various optical principles, such as absorbance, fluorescence, or surface plasmon resonance (SPR).

Piezoelectric biosensors measure changes in mass or frequency that occur when a biomolecule binds to the surface of a piezoelectric crystal. This type of biosensor is based on the principle that piezoelectric materials generate an electrical charge when subjected to mechanical stress, and this charge can be used to detect changes in mass or frequency that are proportional to the amount of biomolecule bound to the surface.

Biosensing techniques have a wide range of applications in fields such as medicine, environmental monitoring, food safety, and biodefense. They can be used to detect and measure a variety of biological molecules, including proteins, nucleic acids, hormones, and small molecules, as well as to monitor biological processes such as cell growth or metabolism.

A transducer is a device that converts one form of energy into another. In the context of medicine and biology, transducers often refer to devices that convert a physiological parameter (such as blood pressure, temperature, or sound waves) into an electrical signal that can be measured and analyzed. Examples of medical transducers include:

1. Blood pressure transducer: Converts the mechanical force exerted by blood on the walls of an artery into an electrical signal.
2. Temperature transducer: Converts temperature changes into electrical signals.
3. ECG transducer (electrocardiogram): Converts the electrical activity of the heart into a visual representation called an electrocardiogram.
4. Ultrasound transducer: Uses sound waves to create images of internal organs and structures.
5. Piezoelectric transducer: Generates an electric charge when subjected to pressure or vibration, used in various medical devices such as hearing aids, accelerometers, and pressure sensors.

Densitometry is a medical technique used to measure the density or degree of opacity of various structures, particularly bones and tissues. It is often used in the diagnosis and monitoring of osteoporosis, a condition characterized by weak and brittle bones. Bone densitometry measures the amount of calcium and other minerals in a segment of bone to determine its strength and density. This information can help doctors assess a patient's risk of fractures and make treatment recommendations. Densitometry is also used in other medical fields, such as mammography, where it is used to measure the density of breast tissue to detect abnormalities and potential signs of cancer.

Norepinephrine, also known as noradrenaline, is a neurotransmitter and a hormone that is primarily produced in the adrenal glands and is released into the bloodstream in response to stress or physical activity. It plays a crucial role in the "fight-or-flight" response by preparing the body for action through increasing heart rate, blood pressure, respiratory rate, and glucose availability.

As a neurotransmitter, norepinephrine is involved in regulating various functions of the nervous system, including attention, perception, motivation, and arousal. It also plays a role in modulating pain perception and responding to stressful or emotional situations.

In medical settings, norepinephrine is used as a vasopressor medication to treat hypotension (low blood pressure) that can occur during septic shock, anesthesia, or other critical illnesses. It works by constricting blood vessels and increasing heart rate, which helps to improve blood pressure and perfusion of vital organs.

Analog-digital conversion, also known as analog-to-digital conversion (ADC) or digitization, is the process of converting a continuous physical quantity or analog signal into a discrete numerical representation or digital signal. This process typically involves sampling the analog signal at regular intervals and then quantizing each sample by assigning it to a specific numerical value within a range. The resulting digital signal can be processed, stored, and transmitted more easily than an analog signal. In medical settings, this type of conversion is often used in devices such as electrocardiograms (ECGs) and blood pressure monitors to convert physiological signals into digital data that can be analyzed and interpreted by healthcare professionals.

A diaphragm is a thin, dome-shaped muscle that separates the chest cavity from the abdominal cavity. It plays a vital role in the process of breathing as it contracts and flattens to draw air into the lungs (inhalation) and relaxes and returns to its domed shape to expel air out of the lungs (exhalation).

In addition, a diaphragm is also a type of barrier method of birth control. It is a flexible dome-shaped device made of silicone that fits over the cervix inside the vagina. When used correctly and consistently, it prevents sperm from entering the uterus and fertilizing an egg, thereby preventing pregnancy.

Computer-assisted signal processing is a medical term that refers to the use of computer algorithms and software to analyze, interpret, and extract meaningful information from biological signals. These signals can include physiological data such as electrocardiogram (ECG) waves, electromyography (EMG) signals, electroencephalography (EEG) readings, or medical images.

The goal of computer-assisted signal processing is to automate the analysis of these complex signals and extract relevant features that can be used for diagnostic, monitoring, or therapeutic purposes. This process typically involves several steps, including:

1. Signal acquisition: Collecting raw data from sensors or medical devices.
2. Preprocessing: Cleaning and filtering the data to remove noise and artifacts.
3. Feature extraction: Identifying and quantifying relevant features in the signal, such as peaks, troughs, or patterns.
4. Analysis: Applying statistical or machine learning algorithms to interpret the extracted features and make predictions about the underlying physiological state.
5. Visualization: Presenting the results in a clear and intuitive way for clinicians to review and use.

Computer-assisted signal processing has numerous applications in healthcare, including:

* Diagnosing and monitoring cardiac arrhythmias or other heart conditions using ECG signals.
* Assessing muscle activity and function using EMG signals.
* Monitoring brain activity and diagnosing neurological disorders using EEG readings.
* Analyzing medical images to detect abnormalities, such as tumors or fractures.

Overall, computer-assisted signal processing is a powerful tool for improving the accuracy and efficiency of medical diagnosis and monitoring, enabling clinicians to make more informed decisions about patient care.

Hypovolemia is a medical condition characterized by a decreased volume of circulating blood in the body, leading to inadequate tissue perfusion and oxygenation. This can occur due to various reasons such as bleeding, dehydration, vomiting, diarrhea, or excessive sweating, which result in a reduced amount of fluid in the intravascular space.

The severity of hypovolemia depends on the extent of fluid loss and can range from mild to severe. Symptoms may include thirst, dry mouth, weakness, dizziness, lightheadedness, confusion, rapid heartbeat, low blood pressure, and decreased urine output. Severe hypovolemia can lead to shock, organ failure, and even death if not treated promptly and effectively.

Pulsatile flow is a type of fluid flow that occurs in a rhythmic, wave-like pattern, typically seen in the cardiovascular system. It refers to the periodic variation in the volume or velocity of a fluid (such as blood) that is caused by the regular beating of the heart. In pulsatile flow, there are periods of high flow followed by periods of low or no flow, which creates a distinct pattern on a graph or tracing. This type of flow is important for maintaining proper function and health in organs and tissues throughout the body.

Photon Absorptiometry is a medical technique used to measure the absorption of photons (light particles) by tissues or materials. In clinical practice, it is often used as a non-invasive method for measuring bone mineral density (BMD). This technique uses a low-energy X-ray beam or gamma ray to penetrate the tissue and then measures the amount of radiation absorbed by the bone. The amount of absorption is related to the density and thickness of the bone, allowing for an assessment of BMD. It can be used to diagnose osteoporosis and monitor treatment response in patients with bone diseases. There are two types of photon absorptiometry: single-photon absorptiometry (SPA) and dual-photon absorptiometry (DPA). SPA uses one energy level, while DPA uses two different energy levels to measure BMD, providing more precise measurements.

Bronchial hyperresponsiveness (BHR) or bronchial hyperreactivity (BH) is a medical term that refers to the increased sensitivity and exaggerated response of the airways to various stimuli. In people with BHR, the airways narrow (constrict) more than usual in response to certain triggers such as allergens, cold air, exercise, or irritants like smoke or fumes. This narrowing can cause symptoms such as wheezing, coughing, chest tightness, and shortness of breath.

BHR is often associated with asthma and other respiratory conditions, including chronic obstructive pulmonary disease (COPD) and bronchiectasis. It is typically diagnosed through a series of tests that measure the degree of airway narrowing in response to various stimuli. These tests may include spirometry, methacholine challenge test, or histamine challenge test.

BHR can be managed with medications such as bronchodilators and anti-inflammatory drugs, which help to relax the muscles around the airways and reduce inflammation. It is also important to avoid triggers that can exacerbate symptoms and make BHR worse.

Body weight is the measure of the force exerted on a scale or balance by an object's mass, most commonly expressed in units such as pounds (lb) or kilograms (kg). In the context of medical definitions, body weight typically refers to an individual's total weight, which includes their skeletal muscle, fat, organs, and bodily fluids.

Healthcare professionals often use body weight as a basic indicator of overall health status, as it can provide insights into various aspects of a person's health, such as nutritional status, metabolic function, and risk factors for certain diseases. For example, being significantly underweight or overweight can increase the risk of developing conditions like malnutrition, diabetes, heart disease, and certain types of cancer.

It is important to note that body weight alone may not provide a complete picture of an individual's health, as it does not account for factors such as muscle mass, bone density, or body composition. Therefore, healthcare professionals often use additional measures, such as body mass index (BMI), waist circumference, and blood tests, to assess overall health status more comprehensively.

A tourniquet is a device or material used to apply pressure around an extremity, typically an arm or leg, with the goal of controlling severe bleeding (hemorrhage) by compressing blood vessels and limiting arterial flow. Tourniquets are usually applied as a last resort when direct pressure and elevation have failed to stop life-threatening bleeding. They should be used cautiously because they can cause tissue damage, nerve injury, or even amputation if left on for too long. In a medical setting, tourniquets are often applied by healthcare professionals in emergency situations; however, there are also specialized tourniquets available for use by trained individuals in the military, first responder communities, and civilians who have undergone proper training.

Regression analysis is a statistical technique used in medicine, as well as in other fields, to examine the relationship between one or more independent variables (predictors) and a dependent variable (outcome). It allows for the estimation of the average change in the outcome variable associated with a one-unit change in an independent variable, while controlling for the effects of other independent variables. This technique is often used to identify risk factors for diseases or to evaluate the effectiveness of medical interventions. In medical research, regression analysis can be used to adjust for potential confounding variables and to quantify the relationship between exposures and health outcomes. It can also be used in predictive modeling to estimate the probability of a particular outcome based on multiple predictors.

Ultrasonography, Doppler, and Duplex are diagnostic medical techniques that use sound waves to create images of internal body structures and assess their function. Here are the definitions for each:

1. Ultrasonography: Also known as ultrasound, this is a non-invasive imaging technique that uses high-frequency sound waves to produce images of internal organs and tissues. A small handheld device called a transducer is placed on the skin surface, which emits and receives sound waves. The returning echoes are then processed to create real-time visual images of the internal structures.
2. Doppler: This is a type of ultrasound that measures the velocity and direction of blood flow in the body by analyzing the frequency shift of the reflected sound waves. It can be used to assess blood flow in various parts of the body, such as the heart, arteries, and veins.
3. Duplex: Duplex ultrasonography is a combination of both gray-scale ultrasound and Doppler ultrasound. It provides detailed images of internal structures, as well as information about blood flow velocity and direction. This technique is often used to evaluate conditions such as deep vein thrombosis, carotid artery stenosis, and peripheral arterial disease.

In summary, ultrasonography is a diagnostic imaging technique that uses sound waves to create images of internal structures, Doppler is a type of ultrasound that measures blood flow velocity and direction, and duplex is a combination of both techniques that provides detailed images and information about blood flow.

An algorithm is not a medical term, but rather a concept from computer science and mathematics. In the context of medicine, algorithms are often used to describe step-by-step procedures for diagnosing or managing medical conditions. These procedures typically involve a series of rules or decision points that help healthcare professionals make informed decisions about patient care.

For example, an algorithm for diagnosing a particular type of heart disease might involve taking a patient's medical history, performing a physical exam, ordering certain diagnostic tests, and interpreting the results in a specific way. By following this algorithm, healthcare professionals can ensure that they are using a consistent and evidence-based approach to making a diagnosis.

Algorithms can also be used to guide treatment decisions. For instance, an algorithm for managing diabetes might involve setting target blood sugar levels, recommending certain medications or lifestyle changes based on the patient's individual needs, and monitoring the patient's response to treatment over time.

Overall, algorithms are valuable tools in medicine because they help standardize clinical decision-making and ensure that patients receive high-quality care based on the latest scientific evidence.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by the persistent obstruction of airflow in and out of the lungs. This obstruction is usually caused by two primary conditions: chronic bronchitis and emphysema. Chronic bronchitis involves inflammation and narrowing of the airways, leading to excessive mucus production and coughing. Emphysema is a condition where the alveoli (air sacs) in the lungs are damaged, resulting in decreased gas exchange and shortness of breath.

The main symptoms of COPD include progressive shortness of breath, chronic cough, chest tightness, wheezing, and excessive mucus production. The disease is often associated with exposure to harmful particles or gases, such as cigarette smoke, air pollution, or occupational dusts and chemicals. While there is no cure for COPD, treatments can help alleviate symptoms, improve quality of life, and slow the progression of the disease. These treatments may include bronchodilators, corticosteroids, combination inhalers, pulmonary rehabilitation, and, in severe cases, oxygen therapy or lung transplantation.

Respiratory physiological phenomena refer to the various mechanical, chemical, and biological processes and functions that occur in the respiratory system during breathing and gas exchange. These phenomena include:

1. Ventilation: The movement of air into and out of the lungs, which is achieved through the contraction and relaxation of the diaphragm and intercostal muscles.
2. Gas Exchange: The diffusion of oxygen (O2) from the alveoli into the bloodstream and carbon dioxide (CO2) from the bloodstream into the alveoli.
3. Respiratory Mechanics: The physical properties and forces that affect the movement of air in and out of the lungs, such as lung compliance, airway resistance, and chest wall elasticity.
4. Control of Breathing: The regulation of ventilation by the central nervous system through the integration of sensory information from chemoreceptors and mechanoreceptors in the respiratory system.
5. Acid-Base Balance: The maintenance of a stable pH level in the blood through the regulation of CO2 elimination and bicarbonate balance by the respiratory and renal systems.
6. Oxygen Transport: The binding of O2 to hemoglobin in the red blood cells and its delivery to the tissues for metabolic processes.
7. Defense Mechanisms: The various protective mechanisms that prevent the entry and colonization of pathogens and foreign particles into the respiratory system, such as mucociliary clearance, cough reflex, and immune responses.

The iliac veins are a pair of large veins in the human body that carry deoxygenated blood from the lower extremities and the pelvic area back to the heart. They are formed by the union of the common iliac veins, which receive blood from the lower abdomen and legs, at the level of the fifth lumbar vertebra.

The combined iliac vein is called the inferior vena cava, which continues upward to the right atrium of the heart. The iliac veins are located deep within the pelvis, lateral to the corresponding iliac arteries, and are accompanied by the iliac lymphatic vessels.

The left common iliac vein is longer than the right because it must cross the left common iliac artery to join the right common iliac vein. The external and internal iliac veins are the two branches of the common iliac vein, with the external iliac vein carrying blood from the lower limbs and the internal iliac vein carrying blood from the pelvic organs.

It is essential to maintain proper blood flow in the iliac veins to prevent deep vein thrombosis (DVT), a condition that can lead to serious complications such as pulmonary embolism.

Skinfold thickness is a measurement of the thickness of the subcutaneous fat layer (the layer of fat directly beneath the skin) at specific sites on the body. It's typically measured using calipers and is expressed in millimeters (mm). This measurement is often used in health assessments to estimate body fat percentage and overall health status. The most commonly used sites for skinfold thickness measurements are the triceps, biceps, suprailiac (just above the iliac crest), subscapular (underneath the shoulder blade), and abdominal areas.

Electrochemistry is a branch of chemistry that deals with the interconversion of electrical energy and chemical energy. It involves the study of chemical processes that cause electrons to move, resulting in the transfer of electrical charge, and the reverse processes by which electrical energy can be used to drive chemical reactions. This field encompasses various phenomena such as the generation of electricity from chemical sources (as in batteries), the electrolysis of substances, and corrosion. Electrochemical reactions are fundamental to many technologies, including energy storage and conversion, environmental protection, and medical diagnostics.

Albuterol is a medication that is used to treat bronchospasm, or narrowing of the airways in the lungs, in conditions such as asthma and chronic obstructive pulmonary disease (COPD). It is a short-acting beta-2 agonist, which means it works by relaxing the muscles around the airways, making it easier to breathe. Albuterol is available in several forms, including an inhaler, nebulizer solution, and syrup, and it is typically used as needed to relieve symptoms of bronchospasm. It may also be used before exercise to prevent bronchospasm caused by physical activity.

The medical definition of Albuterol is: "A short-acting beta-2 adrenergic agonist used to treat bronchospasm in conditions such as asthma and COPD. It works by relaxing the muscles around the airways, making it easier to breathe."

Heart failure is a pathophysiological state in which the heart is unable to pump sufficient blood to meet the metabolic demands of the body or do so only at the expense of elevated filling pressures. It can be caused by various cardiac disorders, including coronary artery disease, hypertension, valvular heart disease, cardiomyopathy, and arrhythmias. Symptoms may include shortness of breath, fatigue, and fluid retention. Heart failure is often classified based on the ejection fraction (EF), which is the percentage of blood that is pumped out of the left ventricle during each contraction. A reduced EF (less than 40%) is indicative of heart failure with reduced ejection fraction (HFrEF), while a preserved EF (greater than or equal to 50%) is indicative of heart failure with preserved ejection fraction (HFpEF). There is also a category of heart failure with mid-range ejection fraction (HFmrEF) for those with an EF between 40-49%.

Air pressure, also known as atmospheric pressure, is the force exerted by the weight of air in the atmosphere on a surface. It is measured in units such as pounds per square inch (psi), hectopascals (hPa), or inches of mercury (inHg). The standard atmospheric pressure at sea level is defined as 101,325 Pa (14.7 psi/1013 hPa/29.92 inHg). Changes in air pressure can be used to predict weather patterns and are an important factor in the study of aerodynamics and respiratory physiology.

Prospective studies, also known as longitudinal studies, are a type of cohort study in which data is collected forward in time, following a group of individuals who share a common characteristic or exposure over a period of time. The researchers clearly define the study population and exposure of interest at the beginning of the study and follow up with the participants to determine the outcomes that develop over time. This type of study design allows for the investigation of causal relationships between exposures and outcomes, as well as the identification of risk factors and the estimation of disease incidence rates. Prospective studies are particularly useful in epidemiology and medical research when studying diseases with long latency periods or rare outcomes.

Implanted electrodes are medical devices that are surgically placed inside the body to interface directly with nerves, neurons, or other electrically excitable tissue for various therapeutic purposes. These electrodes can be used to stimulate or record electrical activity from specific areas of the body, depending on their design and application.

There are several types of implanted electrodes, including:

1. Deep Brain Stimulation (DBS) electrodes: These are placed deep within the brain to treat movement disorders such as Parkinson's disease, essential tremor, and dystonia. DBS electrodes deliver electrical impulses that modulate abnormal neural activity in targeted brain regions.
2. Spinal Cord Stimulation (SCS) electrodes: These are implanted along the spinal cord to treat chronic pain syndromes. SCS electrodes emit low-level electrical pulses that interfere with pain signals traveling to the brain, providing relief for patients.
3. Cochlear Implant electrodes: These are surgically inserted into the cochlea of the inner ear to restore hearing in individuals with severe to profound hearing loss. The electrodes stimulate the auditory nerve directly, bypassing damaged hair cells within the cochlea.
4. Retinal Implant electrodes: These are implanted in the retina to treat certain forms of blindness caused by degenerative eye diseases like retinitis pigmentosa. The electrodes convert visual information from a camera into electrical signals, which stimulate remaining retinal cells and transmit the information to the brain via the optic nerve.
5. Sacral Nerve Stimulation (SNS) electrodes: These are placed near the sacral nerves in the lower back to treat urinary or fecal incontinence and overactive bladder syndrome. SNS electrodes deliver electrical impulses that regulate the function of the affected muscles and nerves.
6. Vagus Nerve Stimulation (VNS) electrodes: These are wrapped around the vagus nerve in the neck to treat epilepsy and depression. VNS electrodes provide intermittent electrical stimulation to the vagus nerve, which has connections to various regions of the brain involved in these conditions.

Overall, implanted electrodes serve as a crucial component in many neuromodulation therapies, offering an effective treatment option for numerous neurological and sensory disorders.

Nitric Oxide Synthase (NOS) is a group of enzymes that catalyze the production of nitric oxide (NO) from L-arginine. There are three distinct isoforms of NOS, each with different expression patterns and functions:

1. Neuronal Nitric Oxide Synthase (nNOS or NOS1): This isoform is primarily expressed in the nervous system and plays a role in neurotransmission, synaptic plasticity, and learning and memory processes.
2. Inducible Nitric Oxide Synthase (iNOS or NOS2): This isoform is induced by various stimuli such as cytokines, lipopolysaccharides, and hypoxia in a variety of cells including immune cells, endothelial cells, and smooth muscle cells. iNOS produces large amounts of NO, which functions as a potent effector molecule in the immune response, particularly in the defense against microbial pathogens.
3. Endothelial Nitric Oxide Synthase (eNOS or NOS3): This isoform is constitutively expressed in endothelial cells and produces low levels of NO that play a crucial role in maintaining vascular homeostasis by regulating vasodilation, inhibiting platelet aggregation, and preventing smooth muscle cell proliferation.

Overall, NOS plays an essential role in various physiological processes, including neurotransmission, immune response, cardiovascular function, and respiratory regulation. Dysregulation of NOS activity has been implicated in several pathological conditions such as hypertension, atherosclerosis, neurodegenerative diseases, and inflammatory disorders.

The esophagus is the muscular tube that connects the throat (pharynx) to the stomach. It is located in the midline of the neck and chest, passing through the diaphragm to enter the abdomen and join the stomach. The main function of the esophagus is to transport food and liquids from the mouth to the stomach for digestion.

The esophagus has a few distinct parts: the upper esophageal sphincter (a ring of muscle that separates the esophagus from the throat), the middle esophagus, and the lower esophageal sphincter (another ring of muscle that separates the esophagus from the stomach). The lower esophageal sphincter relaxes to allow food and liquids to enter the stomach and then contracts to prevent stomach contents from flowing back into the esophagus.

The walls of the esophagus are made up of several layers, including mucosa (a moist tissue that lines the inside of the tube), submucosa (a layer of connective tissue), muscle (both voluntary and involuntary types), and adventitia (an outer layer of connective tissue).

Common conditions affecting the esophagus include gastroesophageal reflux disease (GERD), Barrett's esophagus, esophageal cancer, esophageal strictures, and eosinophilic esophagitis.

Bradykinin is a naturally occurring peptide in the human body, consisting of nine amino acids. It is a potent vasodilator and increases the permeability of blood vessels, causing a local inflammatory response. Bradykinin is formed from the breakdown of certain proteins, such as kininogen, by enzymes called kininases or proteases, including kallikrein. It plays a role in several physiological processes, including pain transmission, blood pressure regulation, and the immune response. In some pathological conditions, such as hereditary angioedema, bradykinin levels can increase excessively, leading to symptoms like swelling, redness, and pain.

Body Mass Index (BMI) is a measure used to assess whether a person has a healthy weight for their height. It's calculated by dividing a person's weight in kilograms by the square of their height in meters. Here is the medical definition:

Body Mass Index (BMI) = weight(kg) / [height(m)]^2

According to the World Health Organization, BMI categories are defined as follows:

* Less than 18.5: Underweight
* 18.5-24.9: Normal or healthy weight
* 25.0-29.9: Overweight
* 30.0 and above: Obese

It is important to note that while BMI can be a useful tool for identifying weight issues in populations, it does have limitations when applied to individuals. For example, it may not accurately reflect body fat distribution or muscle mass, which can affect health risks associated with excess weight. Therefore, BMI should be used as one of several factors when evaluating an individual's health status and risk for chronic diseases.

In the context of medicine and medical devices, calibration refers to the process of checking, adjusting, or confirming the accuracy of a measurement instrument or system. This is typically done by comparing the measurements taken by the device being calibrated to those taken by a reference standard of known accuracy. The goal of calibration is to ensure that the medical device is providing accurate and reliable measurements, which is critical for making proper diagnoses and delivering effective treatment. Regular calibration is an important part of quality assurance and helps to maintain the overall performance and safety of medical devices.

A microelectrode is a small electrode with dimensions ranging from several micrometers to a few tens of micrometers in diameter. They are used in various biomedical applications, such as neurophysiological studies, neuromodulation, and brain-computer interfaces. In these applications, microelectrodes serve to record electrical activity from individual or small groups of neurons or deliver electrical stimuli to specific neural structures with high spatial resolution.

Microelectrodes can be fabricated using various materials, including metals (e.g., tungsten, stainless steel, platinum), metal alloys, carbon fibers, and semiconductor materials like silicon. The design of microelectrodes may vary depending on the specific application, with some common types being sharpened metal wires, glass-insulated metal microwires, and silicon-based probes with multiple recording sites.

The development and use of microelectrodes have significantly contributed to our understanding of neural function in health and disease, enabling researchers and clinicians to investigate the underlying mechanisms of neurological disorders and develop novel therapies for conditions such as Parkinson's disease, epilepsy, and hearing loss.

A bandage is a medical dressing or covering applied to a wound, injury, or sore with the intention of promoting healing or preventing infection. Bandages can be made of a variety of materials such as gauze, cotton, elastic, or adhesive tape and come in different sizes and shapes to accommodate various body parts. They can also have additional features like fasteners, non-slip surfaces, or transparent windows for monitoring the condition of the wound.

Bandages serve several purposes, including:

1. Absorbing drainage or exudate from the wound
2. Protecting the wound from external contaminants and bacteria
3. Securing other medical devices such as catheters or splints in place
4. Reducing swelling or promoting immobilization of the affected area
5. Providing compression to control bleeding or prevent fluid accumulation
6. Relieving pain by reducing pressure on sensitive nerves or structures.

Proper application and care of bandages are essential for effective wound healing and prevention of complications such as infection or delayed recovery.

The Respiratory System is a complex network of organs and tissues that work together to facilitate the process of breathing, which involves the intake of oxygen and the elimination of carbon dioxide. This system primarily includes the nose, throat (pharynx), voice box (larynx), windpipe (trachea), bronchi, bronchioles, lungs, and diaphragm.

The nostrils or mouth take in air that travels through the pharynx, larynx, and trachea into the lungs. Within the lungs, the trachea divides into two bronchi, one for each lung, which further divide into smaller tubes called bronchioles. At the end of these bronchioles are tiny air sacs known as alveoli where the exchange of gases occurs. Oxygen from the inhaled air diffuses through the walls of the alveoli into the bloodstream, while carbon dioxide, a waste product, moves from the blood to the alveoli and is exhaled out of the body.

The diaphragm, a large muscle that separates the chest from the abdomen, plays a crucial role in breathing by contracting and relaxing to change the volume of the chest cavity, thereby allowing air to flow in and out of the lungs. Overall, the Respiratory System is essential for maintaining life by providing the body's cells with the oxygen needed for metabolism and removing waste products like carbon dioxide.

Enzyme inhibitors are substances that bind to an enzyme and decrease its activity, preventing it from catalyzing a chemical reaction in the body. They can work by several mechanisms, including blocking the active site where the substrate binds, or binding to another site on the enzyme to change its shape and prevent substrate binding. Enzyme inhibitors are often used as drugs to treat various medical conditions, such as high blood pressure, abnormal heart rhythms, and bacterial infections. They can also be found naturally in some foods and plants, and can be used in research to understand enzyme function and regulation.

Eructation is the medical term for belching or burping. It refers to the act of expelling gas from the upper digestive tract (esophagus and stomach) through the mouth. This voluntary or involuntary action helps to relieve symptoms of bloating, discomfort, or pain caused by excessive gas build-up in the stomach. Eructation often occurs after swallowing air while eating or drinking quickly, consuming carbonated beverages, or experiencing anxiety or stress. In some cases, frequent eructations may indicate an underlying digestive disorder such as gastroesophageal reflux disease (GERD) or gastritis.

A chronic disease is a long-term medical condition that often progresses slowly over a period of years and requires ongoing management and care. These diseases are typically not fully curable, but symptoms can be managed to improve quality of life. Common chronic diseases include heart disease, stroke, cancer, diabetes, arthritis, and COPD (chronic obstructive pulmonary disease). They are often associated with advanced age, although they can also affect children and younger adults. Chronic diseases can have significant impacts on individuals' physical, emotional, and social well-being, as well as on healthcare systems and society at large.

Dizziness is a term used to describe a range of sensations, such as feeling lightheaded, faint, unsteady, or a false sense of spinning or moving. Medically, dizziness is often described as a non-specific symptom that can be caused by various underlying conditions or factors. These may include:

1. Inner ear disorders (such as benign paroxysmal positional vertigo, labyrinthitis, vestibular neuronitis, or Meniere's disease)
2. Cardiovascular problems (like low blood pressure, arrhythmias, or orthostatic hypotension)
3. Neurological issues (such as migraines, multiple sclerosis, or stroke)
4. Anxiety disorders and panic attacks
5. Side effects of medications
6. Dehydration or overheating
7. Infections (like viral infections or bacterial meningitis)
8. Head or neck injuries
9. Low blood sugar levels (hypoglycemia)

It is essential to consult a healthcare professional if you experience persistent dizziness, as it can be a sign of a more severe underlying condition. The appropriate treatment will depend on the specific cause of the dizziness.

Bed rest is a medical recommendation for a person to limit their activities and remain in bed for a period of time. It is often ordered by healthcare providers to help the body recover from certain medical conditions or treatments, such as:

* Infections
* Pregnancy complications
* Recent surgery
* Heart problems
* Blood pressure fluctuations
* Bleeding
* Bone fractures
* Certain neurological conditions

The duration of bed rest can vary depending on the individual's medical condition and response to treatment. While on bed rest, patients are typically advised to change positions frequently to prevent complications such as bedsores, blood clots, and muscle weakness. They may also receive physical therapy, occupational therapy, or other treatments to help maintain their strength and mobility during this period.

Exhalation is the act of breathing out or exhaling, which is the reverse process of inhalation. During exhalation, the diaphragm relaxes and moves upwards, while the chest muscles also relax, causing the chest cavity to decrease in size. This decrease in size puts pressure on the lungs, causing them to deflate and expel air.

Exhalation is a passive process that occurs naturally after inhalation, but it can also be actively controlled during activities such as speaking, singing, or playing a wind instrument. In medical terms, exhalation may also be referred to as expiration.

Endothelin A (ETA) receptor is a type of G protein-coupled receptor that is activated by the peptide hormone endothelin-1, endothelin-2, and endothelin-3. It is widely expressed in various tissues and organs, including vascular smooth muscle cells, cardiac myocytes, fibroblasts, and kidney cells. Activation of ETA receptor leads to vasoconstriction, increased cell proliferation, and fibrosis, which contribute to the development of hypertension, heart failure, and chronic kidney disease. Therefore, ETA receptor antagonists have been developed as potential therapeutic agents for these conditions.

Physiological monitoring is the continuous or intermittent observation and measurement of various body functions or parameters in a patient, with the aim of evaluating their health status, identifying any abnormalities or changes, and guiding clinical decision-making and treatment. This may involve the use of specialized medical equipment, such as cardiac monitors, pulse oximeters, blood pressure monitors, and capnographs, among others. The data collected through physiological monitoring can help healthcare professionals assess the effectiveness of treatments, detect complications early, and make timely adjustments to patient care plans.

Stroke volume is a term used in cardiovascular physiology and medicine. It refers to the amount of blood that is pumped out of the left ventricle of the heart during each contraction (systole). Specifically, it is the difference between the volume of blood in the left ventricle at the end of diastole (when the ventricle is filled with blood) and the volume at the end of systole (when the ventricle has contracted and ejected its contents into the aorta).

Stroke volume is an important measure of heart function, as it reflects the ability of the heart to pump blood effectively to the rest of the body. A low stroke volume may indicate that the heart is not pumping efficiently, while a high stroke volume may suggest that the heart is working too hard. Stroke volume can be affected by various factors, including heart disease, high blood pressure, and physical fitness level.

The formula for calculating stroke volume is:

Stroke Volume = End-Diastolic Volume - End-Systolic Volume

Where end-diastolic volume (EDV) is the volume of blood in the left ventricle at the end of diastole, and end-systolic volume (ESV) is the volume of blood in the left ventricle at the end of systole.

The abdominal muscles, also known as the abdominals or abs, are a group of muscles in the anterior (front) wall of the abdominopelvic cavity. They play a crucial role in maintaining posture, supporting the trunk, and facilitating movement of the torso. The main abdominal muscles include:

1. Rectus Abdominis: These are the pair of long, flat muscles that run vertically along the middle of the anterior abdominal wall. They are often referred to as the "six-pack" muscles due to their visible, segmented appearance in well-trained individuals. The primary function of the rectus abdominis is to flex the spine, allowing for actions such as sitting up from a lying down position or performing a crunch exercise.

2. External Obliques: These are the largest and most superficial of the oblique muscles, located on the lateral (side) aspects of the abdominal wall. They run diagonally downward and forward from the lower ribs to the iliac crest (the upper part of the pelvis) and the pubic tubercle (a bony prominence at the front of the pelvis). The external obliques help rotate and flex the trunk, as well as assist in side-bending and exhalation.

3. Internal Obliques: These muscles lie deep to the external obliques and run diagonally downward and backward from the lower ribs to the iliac crest, pubic tubercle, and linea alba (the strong band of connective tissue that runs vertically along the midline of the abdomen). The internal obliques help rotate and flex the trunk, as well as assist in forced exhalation and increasing intra-abdominal pressure during actions such as coughing or lifting heavy objects.

4. Transversus Abdominis: This is the deepest of the abdominal muscles, located inner to both the internal obliques and the rectus sheath (a strong, fibrous covering that surrounds the rectus abdominis). The transversus abdominis runs horizontally around the abdomen, attaching to the lower six ribs, the thoracolumbar fascia (a broad sheet of connective tissue spanning from the lower back to the pelvis), and the pubic crest (the front part of the pelvic bone). The transversus abdominis helps maintain core stability by compressing the abdominal contents and increasing intra-abdominal pressure.

Together, these muscles form the muscular "corset" of the abdomen, providing support, stability, and flexibility to the trunk. They also play a crucial role in respiration, posture, and various movements such as bending, twisting, and lifting.

Asthma is a chronic respiratory disease characterized by inflammation and narrowing of the airways, leading to symptoms such as wheezing, coughing, shortness of breath, and chest tightness. The airway obstruction in asthma is usually reversible, either spontaneously or with treatment.

The underlying cause of asthma involves a combination of genetic and environmental factors that result in hypersensitivity of the airways to certain triggers, such as allergens, irritants, viruses, exercise, and emotional stress. When these triggers are encountered, the airways constrict due to smooth muscle spasm, swell due to inflammation, and produce excess mucus, leading to the characteristic symptoms of asthma.

Asthma is typically managed with a combination of medications that include bronchodilators to relax the airway muscles, corticosteroids to reduce inflammation, and leukotriene modifiers or mast cell stabilizers to prevent allergic reactions. Avoiding triggers and monitoring symptoms are also important components of asthma management.

There are several types of asthma, including allergic asthma, non-allergic asthma, exercise-induced asthma, occupational asthma, and nocturnal asthma, each with its own set of triggers and treatment approaches. Proper diagnosis and management of asthma can help prevent exacerbations, improve quality of life, and reduce the risk of long-term complications.

In medical terms, constriction refers to the narrowing or tightening of a body part or passageway. This can occur due to various reasons such as spasms of muscles, inflammation, or abnormal growths. It can lead to symptoms like difficulty in breathing, swallowing, or blood flow, depending on where it occurs. For example, constriction of the airways in asthma, constriction of blood vessels in hypertension, or constriction of the esophagus in certain digestive disorders.

Ultrasonography, Doppler, color is a type of diagnostic ultrasound technique that uses the Doppler effect to produce visual images of blood flow in vessels and the heart. The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the source of the wave. In this context, it refers to the change in frequency of the ultrasound waves as they reflect off moving red blood cells.

In color Doppler ultrasonography, different colors are used to represent the direction and speed of blood flow. Red typically represents blood flowing toward the transducer (the device that sends and receives sound waves), while blue represents blood flowing away from the transducer. The intensity or brightness of the color is proportional to the velocity of blood flow.

Color Doppler ultrasonography is often used in conjunction with grayscale ultrasound imaging, which provides information about the structure and composition of tissues. Together, these techniques can help diagnose a wide range of conditions, including heart disease, blood clots, and abnormalities in blood flow.

Nonparametric statistics is a branch of statistics that does not rely on assumptions about the distribution of variables in the population from which the sample is drawn. In contrast to parametric methods, nonparametric techniques make fewer assumptions about the data and are therefore more flexible in their application. Nonparametric tests are often used when the data do not meet the assumptions required for parametric tests, such as normality or equal variances.

Nonparametric statistical methods include tests such as the Wilcoxon rank-sum test (also known as the Mann-Whitney U test) for comparing two independent groups, the Wilcoxon signed-rank test for comparing two related groups, and the Kruskal-Wallis test for comparing more than two independent groups. These tests use the ranks of the data rather than the actual values to make comparisons, which allows them to be used with ordinal or continuous data that do not meet the assumptions of parametric tests.

Overall, nonparametric statistics provide a useful set of tools for analyzing data in situations where the assumptions of parametric methods are not met, and can help researchers draw valid conclusions from their data even when the data are not normally distributed or have other characteristics that violate the assumptions of parametric tests.

A case-control study is an observational research design used to identify risk factors or causes of a disease or health outcome. In this type of study, individuals with the disease or condition (cases) are compared with similar individuals who do not have the disease or condition (controls). The exposure history or other characteristics of interest are then compared between the two groups to determine if there is an association between the exposure and the disease.

Case-control studies are often used when it is not feasible or ethical to conduct a randomized controlled trial, as they can provide valuable insights into potential causes of diseases or health outcomes in a relatively short period of time and at a lower cost than other study designs. However, because case-control studies rely on retrospective data collection, they are subject to biases such as recall bias and selection bias, which can affect the validity of the results. Therefore, it is important to carefully design and conduct case-control studies to minimize these potential sources of bias.

I'm sorry for any confusion, but "spectrum analysis" is not a commonly used medical term. Spectrum analysis is a term that is more frequently used in the fields of physics, mathematics, and engineering to describe the process of breaking down a signal or a wave into its different frequencies and amplitudes, creating a visual representation called a spectrum.

If you have any concerns about a medical issue, I would recommend consulting with a healthcare professional for accurate information and guidance.

Venous thrombosis is a medical condition characterized by the formation of a blood clot (thrombus) in the deep veins, often in the legs (deep vein thrombosis or DVT), but it can also occur in other parts of the body such as the arms, pelvis, or lungs (pulmonary embolism).

The formation of a venous thrombus can be caused by various factors, including injury to the blood vessel wall, changes in blood flow, and alterations in the composition of the blood. These factors can lead to the activation of clotting factors and platelets, which can result in the formation of a clot that blocks the vein.

Symptoms of venous thrombosis may include swelling, pain, warmth, and redness in the affected area. In some cases, the clot can dislodge and travel to other parts of the body, causing potentially life-threatening complications such as pulmonary embolism.

Risk factors for venous thrombosis include advanced age, obesity, smoking, pregnancy, use of hormonal contraceptives or hormone replacement therapy, cancer, recent surgery or trauma, prolonged immobility, and a history of previous venous thromboembolism. Treatment typically involves the use of anticoagulant medications to prevent further clotting and dissolve existing clots.

"Electrical equipment and supplies" refer to devices, apparatus, or tools that operate using electricity and are used in medical settings for various healthcare purposes. These items can include, but are not limited to:

1. Medical instruments: Devices used for diagnostic or therapeutic purposes, such as electrocardiogram (ECG) machines, ultrasound machines, and defibrillators.
2. Patient care equipment: Items that provide support or monitoring for patients, including ventilators, oxygen concentrators, infusion pumps, and patient monitors.
3. Laboratory equipment: Instruments used in medical laboratories for testing and analysis, such as centrifuges, microscopes, and spectrophotometers.
4. Imaging equipment: Devices that generate images of the body's internal structures or functions, like X-ray machines, MRI scanners, CT scanners, and mammography systems.
5. Lighting and power distribution: Electrical outlets, switches, lighting fixtures, and other components used to provide electricity and illumination in medical facilities.
6. Communication devices: Equipment used for transmitting or receiving information, such as intercoms, pagers, and wireless networks.
7. Data management systems: Computers, servers, and storage devices that manage patient records, medical images, and other healthcare-related data.
8. Sterilization equipment: Devices used to clean and disinfect medical instruments and supplies, such as autoclaves and ultrasonic cleaners.
9. Building management systems: Electrical controls for heating, ventilation, air conditioning (HVAC), and other environmental systems in healthcare facilities.
10. Safety equipment: Devices used to protect patients, staff, and visitors from electrical hazards, such as ground-fault circuit interrupters (GFCIs) and arc-fault circuit interrupters (AFCIs).

In medical terms, the skin is the largest organ of the human body. It consists of two main layers: the epidermis (outer layer) and dermis (inner layer), as well as accessory structures like hair follicles, sweat glands, and oil glands. The skin plays a crucial role in protecting us from external factors such as bacteria, viruses, and environmental hazards, while also regulating body temperature and enabling the sense of touch.

I'm sorry for any confusion, but "myography" is not a recognized term in the field of medicine or medical terminology. It may be possible that you have misspelled or misremembered a related term. If you meant "myology," that refers to the study of muscles, their structure, function, and disorders. If you had a different term in mind, please provide it so I can give you a more accurate response.

"Adiposity" is a medical term that refers to the condition of having an excessive amount of fat in the body. It is often used to describe obesity or being significantly overweight. Adipose tissue, which is the technical name for body fat, is important for many bodily functions, such as storing energy and insulating the body. However, an excess of adipose tissue can lead to a range of health problems, including heart disease, diabetes, and certain types of cancer.

There are different ways to measure adiposity, including body mass index (BMI), waist circumference, and skinfold thickness. BMI is the most commonly used method and is calculated by dividing a person's weight in kilograms by their height in meters squared. A BMI of 30 or higher is considered obese, while a BMI between 25 and 29.9 is considered overweight. However, it's important to note that BMI may not accurately reflect adiposity in some individuals, such as those with a lot of muscle mass.

In summary, adiposity refers to the condition of having too much body fat, which can increase the risk of various health problems.

Regional specific airway resistance determined by electrical impedance tomography and body plethysmography. ...
Impedance cardiography (ICG), also referred to as electrical impedance plethysmography (EIP) or Thoracic Electrical ... Impedance Plethysmography". www.bem.fi. Kubicek W.G., Witsoe, D.A., Patterson, R.P., Mosharrata, M.A., Karnegis, J.N., From, A. ... sense the impedance signals and the ECG signal ICG measures the baseline impedance (resistance) to this current With each ... The use of impedance cardiography in psychophysiological research was pioneered by the publication of an article by Miller and ...
Impedance plethysmography. Its the clinical outcome that counts. Chest. 1994 Nov. 106(5):1317-8. [QxMD MEDLINE Link]. [Full ... Impedance plethysmography (IPG) is a noninvasive test that generates no images, relying instead on unfamiliar technology. [15] ...
impedance plethysmography (IPG). measures venous flow of the extremities with a plethysmograph to detect clots by measuring ... changes in blood volume & resistance (impedance) in the vein; used to detect deep vein thrombosis. ...
Calculating Respiration Parameters Using Impedance Plethysmography WO2010027771A1 (en) 2008-08-27. 2010-03-11. Edwards ... Impedance-based measurements of cardiac parameters such as stroke volume are known in the art, such as an impedance lead having ... The set of impedance electrodes 170, 172, 174 and 176 is coupled by a set of conductors 178 and is formed as a lead that is ... A pair of pace/sense electrodes 140, 142, a pressure sensor 160, and a plurality, e.g., four, impedance measuring electrodes ...
A comparison between ultrasound techniques, air displacement plethysmography and bioelectrical impedance vs. dual-energy X-ray ... Bioelectrical Impedance Analysis. Talma et al (2013) stated that bioelectrical impedance analysis (BIA) is a practical method ... Plethysmography for determination of lung volumes and, when performed, airway resistance 97810 Acupuncture, one or more needles ... Bioelectrical impedance analysis (BIA) meets many of the criteria required in this environment and appears to be effective for ...
Keywords: Plasma viscosity, Erythrocyte aggregation, fibrinogen, deep vein thrombosis, impedance plethysmography, breast cancer ... leukocytes and fibrinogen levels were estimated and impedance plethysmography (IPG) was performed for screening of deep vein ...
Stroke volume (SV) was estimated using impedance cardiography; forearm blood flow (FBF) estimated by venous occlusion ... estimated by venous occlusion plethysmography and forearm vascular resistance (FVR) was calculated from FBF and SBP. Total ... Stroke volume (SV) was estimated using impedance cardiography; forearm blood flow (FBF) ... plethysmography and forearm vascular resistance (FVR) was calculated from FBF and SBP. Total peripheral resistance (TPR) was ...
The IsenseU-BP+ device presented in this article measures single channel ECG, impedance cardiography and photo plethysmography ... Truly unobtrusive wearable devices combining impedance cardiography with other sensors may be one possible solution. ...
Thus, this study aims to identify the differences between field methods, such as bioelectrical impedance (BIA) and skinfold ... bioelectrical impedance analysis, air-displacement plethysmography, and body mass index percentiles. J. Pediatr. Endocrinol. ... Bioelectrical impedance analysis-Part II: Utilization in clinical practice. Clin. Nutr. 2004, 23, 1430-1453. [Google Scholar] [ ... Boneva-Asiova, Z.; Boyanov, M.A. Body composition analysis by leg-to-leg bioelectrical impedance and dual-energy X-ray ...
Global Body Composition Analyzer Market by Product Type (Air Displacement Plethysmography Equipment, Bio-Impedance Analyzers, ... 3.1 Europe Bio-impedance Analyzer Market by Country. 3.2 Europe Dual Energy X-ray Absorptiometry Equipment Market by Country. ... Based on Product Type, the market is segmented into Bio-impedance Analyzer, Dual Energy X-ray Absorptiometry Equipment, ... 3.4 Europe Air Displacement Plethysmography Equipment Market by Country. 3.5 Europe Hydrostatic Weighing Equipment Market by ...
BACKGROUND: Bioelectrical impedance analysis (BIA) is a noninvasive rapid and simple bedside technique that can be used to ...
Comparison of body fat results from 4 bioelectrical impedance analysis devices vs. air displacement plethysmography in American ...
Impedance Plethysmography and Compression ultrasound scanning of the left leg veins also useful in aiding diagnosis of DVT and ...
Bioelectric impedance analysis. In this method a low-grade, imperceptible electrical current is sent through the body, and ... weighing and air-displacement plethysmography (e.g., the "BOD POD"). ...
BMI strongly correlate with BF % estimated by bioelectrical impedance, in this sub population of South Asian adults. This ... was estimated from bioelectrical impedance analysis. Pearsons correlation coefficient(r) was calculated to see the ... dual energy X-ray absorptiometry and air displacement plethysmography [9, 18]. Large population studies conducted even have ... We used Bioelectrical Impedance Analysis (BIA) method to estimate the Body fat %. BIA is known to provide a rapid, non-invasive ...
Body plethysmography measurements are to be performed annually at selected sites, with recording of static lung volumes, airway ... body impedance, resting oxygen saturation and 6-min walking distance. ... Assessments include pulmonary function measurements (spirometry, impulse oscillometry and plethysmography), chest computed ...
Respiratory impedance plethysmography (RIP) belts (Respitrace, Ardsley, NY) were placed around the upper rib cage and mid- ... 36]Respiratory impedance plethysmography measurements, tidal volume, and EMGs were recorded simultaneously to ensure stability ... Abdominal dimensions measured by respiratory impedance plethysmography show the phases of breathing, with an increase in ... Abdominal dimensions measured by respiratory impedance plethysmography show the phases of breathing, with an increase in ...
PLETHYSMOGR IMPEDANCE. Entry Term(s). Impedance Plethysmography Rheography Public MeSH Note. 66. History Note. 66. Date ... Plethysmography, Impedance Preferred Concept UI. M0017038. Scope Note. Recording changes in electrical impedance between ... Plethysmography [E01.370.370.610] * Photoplethysmography [E01.370.370.610.600] * Plethysmography, Impedance [E01.370.370.610. ... Plethysmography, Impedance Preferred Term Term UI T032357. Date01/01/1999. LexicalTag NON. ThesaurusID NLM (1966). ...
Currently, bioelectric impedance analysis is the most popular method for body fat measurement and works on the principle of ... computerized tomography and air displacement plethysmography. Ultrasound technique can also be used for accurate assessment of ... Body fat analyzers are also known as impedance meters is a tool for accurate assessment of body fat and this identify risk ... The different body fat analysis methods include hydrostatic weighing or underwater weighing, bioelectric impedance analysis, ...
Effect of different modes of cheek support on respiratory impedance measurements. K. Leemans, K. De Soomer, R. Heyndrickx, W. ... Can impulse oscillometry and body plethysmography differentiate response to two salbutamol doses?. R. Kodgule, N. Vanjare, S. ... Tidal breathing flow-volume curves with impedance pneumography during expiratory loading. V. P. Seppä, M. Uitto, J. Viik ( ... Correlation of spirometry with impulse oscillometry, body plethysmography and DLCO. R. Kodgule, N. Vanjare, S. Rasam, S. ...
Impedance Plethysmography, although non-invasive. is not as reliable.. This presentation reviews current methods of detection ... Impedance Plethysmography, although non-invasiveis not as reliable.This presentation reviews current methods of detection and ... Impedance Plethysmography, although non-invasiveis not as reliable.This presentation reviews current methods of detection and ... Impedance Plethysmography, although non-invasiveis not as reliable.This presentation reviews current methods of detection and ...
... estimating changes in fat-free mass via methods such as bioelectrical impedance analysis (BIA), dual-energy X-ray ... absorptiometry (DXA) and whole body air displacement plethysmography (BodPod). Given creatines ability to increase ...
... while cautioning practitioners that impedance plethysmography may fail to detect airway obstruction. The Task Force emphasizes ...
Bioelectric Impedance Analysis (BIA). Bioelectric Impedance Analysis (BIA) assesses the amount of water in the body. The method ... Air displacement plethysmography (Bod Pod). Bod Pod is an accurate and estimates percent body fat by measuring the amount of ... air displacement plethysmography (Bod Pod), (2) skinfold measurement, and (3) bioelectric analysis (BIA). ...
Epsilon-Tube Filtering: Reduction of High-Amplitude Motion Artifacts From Impedance Plethysmography Signal. Food Wastage ... Examples of applications of plethysmog-raphy in medicine are measuring lung volume, blood volumevariations, blood flow, muscle ... Reduction Management Android App Measuring electrical impedance of different segments of thebody, a.k.a. IP, has been widely ...
Impedance plethysmography measures changes in venous blood volume and flow.. Nursing Management. 1. Promote resolution of ...
Plethysmography, Impedance (MeSH) * Principal Component Analysis (MeSH) * Reproducibility of Results (MeSH) * Sensitivity and ... Electrical impedance tomography, EIT, is an imaging modality in which the internal conductivity distribution of an object is ...
Impedance Phlebography Impedance Plethysmography impede Impedimenta Impekoven, Niddy (1904-2002) Impekoven, Niddy (1904-) ...

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