• The efferent fiber is a long process projecting far from the neuron's body that carries nerve impulses away from the central nervous system toward the peripheral effector organs (mainly muscles and glands). (wikipedia.org)
  • In the CNS, afferent and efferent projections can be from the perspective of any given brain region. (wikipedia.org)
  • That is, each brain region has its own unique set of afferent and efferent projections. (wikipedia.org)
  • Besides motor nerves, there are efferent sensory nerves that often serve to adjust the sensitivity of the signal relayed by the afferent sensory nerve. (wikipedia.org)
  • Both afferent and efferent come from French, evolved from Latin (the basis of many terms in medicine and biology) for the terms, respectively, ad ferens (Latin verb ferre: carry), meaning carrying into, and ex ferens, meaning carrying away (ad literally means to, and e = ex means from). (wikipedia.org)
  • Ad and ex give an easy mnemonic device for remembering the relationship between afferent and efferent: afferent connection arrives and an efferent connection exits. (wikipedia.org)
  • Afferent and efferent are connected to affect and effect through their common Latin roots: Afferent nerves affect the subject, whereas efferent nerves allow the subject to effect change. (wikipedia.org)
  • A nerve is composed of thousands of axons ranging in size from less than 1 to 20 mm in diameter.Nerves are made up of afferent and efferent fibers. (evokedpotential.com)
  • Nerves with axons that conduct electrochemical impulses toward the central nervous system (CNS) are afferent, nerves with axons that conduct impulses away from the CNS are efferent, and nerves with both afferent and efferent axons are mixed. (unboundmedicine.com)
  • This also evaluates conduction between the limb and the spinal cord, but in this case, the afferent impulses (those going towards the spinal cord) are in sensory nerves while the efferent impulses (those coming from the spinal cord) are in motor nerves. (wikidoc.org)
  • There are three broad functional classifications of nerves - sensory (afferent), intermediate and motor (efferent). (teachmeanatomy.info)
  • The opposite direction of neural activity is afferent conduction, which carries impulses by way of the afferent nerve fibers of sensory neurons. (wikipedia.org)
  • Amir R, Devor M (2000) Functional cross-excitation between afferent A- and C-neurons in dorsal root ganglia. (yale.edu)
  • Delio DA, Reuhl KR, Lowndes HE (1992) Ectopic impulse generation in dorsal root ganglion neurons during methylmercury intoxication: an electrophysiological and morphological study. (yale.edu)
  • Communication between different parts of the nervous system depends on the propagation of nerve impulse (action potentials) along the axons of neurons. (evokedpotential.com)
  • Your neurons work to conduct nerve impulses. (healthline.com)
  • Some of these spindle afferents synapse on second-order neurons which conduct the stretch information up the spinal cord to the cerebellum and even the cerebral cortex. (humanneurobiology.com)
  • Other spindle afferents directly excite large alpha motor neurons innervating skeletal muscle fibers. (humanneurobiology.com)
  • If tone in a particular muscle decreases, allowing the muscle to lengthen, the spindles become stretched and trigger increased impulse firing in the spindle afferents, thereby increasing the firing rate of the alpha motor neurons to that same muscle and causing it to contract. (humanneurobiology.com)
  • In the peripheral nervous system, the axons of neurons are grouped together to form nerves. (teachmeanatomy.info)
  • The high conduction velocity of this initial burst is consistent with the activation of a Mauthner neuron, one of a pair of giant reticulospinal neurons in fish and amphibians. (biologists.com)
  • These unmyelinated C-fibers transmit itch impulses to the ipsilateral dorsal horn of the spinal cord, 3 where they synapse with itch-specific secondary neurons. (asahq.org)
  • Primary nociceptive afferents ascend contralaterally and stimulate spinothalamic and spinoreticular neurons in the dorsal horn of the spinal cord by mediating neuro-transmitters, such as glutamate, aspartate, substance P, and calcitonin gene-related peptide. (diseasesdic.com)
  • These drugs change and regulate neural conduction through anxi- ety circuits and central vestibular neurons that respond to movement. (otoneurologia.org.br)
  • Neurons function in the initiation and conduction of impulses. (mhmedical.com)
  • They transmit impulses to other neurons or cells by releasing neurotransmitters at synapses. (mhmedical.com)
  • A neuron of the retina that receives impulses from bipolar neurons. (mhmedical.com)
  • Specialized afferent neurons capable of transducing sensory stimuli into NERVE IMPULSES to be transmitted to the CENTRAL NERVOUS SYSTEM. (lookformedical.com)
  • In the context of a given brain region, afferents are arriving fibers while efferents are exiting fibers. (wikipedia.org)
  • Lisney SJ, Devor M (1987) Afterdischarge and interactions among fibers in damaged peripheral nerve in the rat. (yale.edu)
  • the fibers are subdivided into subgroups labeled with Greek letter having successively higher stimulation thresholds and slower conduction velocities. (evokedpotential.com)
  • The neural elements of somatosensory receptors in the hands and feet represent the distal extreme of long afferent fibers, and thus, are par- ticularly vulnerable in the distal axonopathies. (cdc.gov)
  • In contrast to the motor system, the cell bodies of the afferent sensory fibers lie outside the spinal cord, in dorsal root ganglia. (msdmanuals.com)
  • Peripheral nerves are bundles of nerve fibers. (msdmanuals.com)
  • The sensory (afferent) division carries sensory signals by way of afferent nerve fibers from receptors in the central nervous system (CNS). (medscape.com)
  • The free nerve endings of primary afferent A delta and C fibers are responsible for nociception ( Table 133-1 ). (mhmedical.com)
  • The axons of the A delta are thinly myelinated with a faster conduction speed of 5-15 m/s in contrast to the unmyelinated C fibers with a conduction speed of 1-2 m/s. (mhmedical.com)
  • The mechanothermal fibers had a mean RF size of 18.9 ± 3.2 mm 2 (SE), a mean conduction velocity of 0.8 ± 0.1 m/s, mean thresholds of 43.6 ± 0.6°C for radiant heat and 5.95 ± 0.59 bars for mechanical stimulation, and no spontaneous activity. (johnshopkins.edu)
  • In contrast, warm fibers had punctate RFs, a mean conduction velocity of 1.1 ± 0.1 m/s, heat thresholds of less than 1°C above skin temperature, no response to mechanical stimulation, and a resting level of activity in warm skin that was suppressed by cooling. (johnshopkins.edu)
  • The cumulative number of impulses evoked during each stimulation in the nociceptive afferents increased monotonically as a function of stimulus temperature over the range described by humans as increasingly painful (45-50°C). Nociceptive fibers showed little or no response to stimulus temperatures less than 45°C that elicited in humans sensations primarily of warmth but not pain. (johnshopkins.edu)
  • In contrast, the cumulative impulse count during stimulation of each warm fiber increased monotonically with stimulus temperature over the range of 39-43°C. However, for stimuli of 41-49°C the cumulative impulse count in warm fibers was nonmonotonic with stimulus temperature. (johnshopkins.edu)
  • b) that activity in warm fibers may encode the intensity of warmth at lower stimulus temperatures, but is unlikely to provide a peripheral mechanism for encoding the intensity of painful stimulation at higher stimulus temperatures. (johnshopkins.edu)
  • When stretched, muscle spindles become activated, causing an increase in the impulse firing rate of afferent nerve fibers from the spindles to the spinal cord. (humanneurobiology.com)
  • In a three year LSU Pain Center study it was found that the nerve requiring the greatest voltage to cause conduction of the A-delta (Fast Pain) fibers identified nerve root pathology with 95% sensitivity. (wikidoc.org)
  • Set of nerve fibers conducting impulses from olfactory receptors to the cerebral cortex. (lookformedical.com)
  • Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body. (lookformedical.com)
  • Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM. (lookformedical.com)
  • The afferent input from these fibers inhibits propagation of nociception carried in the small, unmyelinated C fibers by blocking transmission along these fibers to the target or T cells located in the substantia gelatinosa (laminae 2 and 3) of the dorsal horn. (medscape.com)
  • When painful peripheral stimulation occurs, however, the information carried by C fibers reaches the T cells and opens the gate, allowing pain transmission centrally to the thalamus and cortex, where it is interpreted as pain. (medscape.com)
  • The proposed mechanism for closing the gate is inhibition of the C-fiber nociception by impulses in activated myelinated fibers. (medscape.com)
  • Ultrasound Diathermy Modality generates deep therapeutic heat into the musculoskeletal tissues along with other non-thermal biologic effects: temporarily blocks peripheral nerve impulses (small C-fibers), improves hypertonicity of musculoskeletal spams, alters spinal reflexes, increase the local metabolic rate, increase peripheral arterial blood flow and increase membrane permeability. (injurysolutions.com)
  • Impulses are conducted by a part of myelinated A-delta fibers and unmyelinated-C, which are produced by noxious stimuli and transmit sensations that are considered pain. (diseasesdic.com)
  • Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM. (lookformedical.com)
  • In confirmation of previous work, the mean amplitude of LG-S EPSPs evoked by stimulation of axotomized afferents was significantly larger than that measured in untreated rats (3.9 ± 0.34 and 2.3 ± 0.19 mV, respectively). (jneurosci.org)
  • Burchiel KJ (1984) Spontaneous impulse generation in normal and denervated dorsal root ganglia: sensitivity to alpha-adrenergic stimulation and hypoxia. (yale.edu)
  • Motor NCS are performed by electrical stimulation of a peripheral nerve and recording from a muscle supplied by this nerve. (wikidoc.org)
  • The time it takes for the electrical impulse to travel from the stimulation to the recording site is measured. (wikidoc.org)
  • Sensory NCS are performed by electrical stimulation of a peripheral nerve and recording from a purely-sensory portion of the nerve, such as on a finger. (wikidoc.org)
  • an elongated protrusion of the neuron that conducts impulses away from the cell. (ashp.org)
  • The subjective magnitude of warmth and pain sensations in humans and the cumulative impulse count evoked by each stimulus in warm and nociceptive afferents varied inversely with the number, delivery rate, and intensity of preceding stimulations. (johnshopkins.edu)
  • Nerve conduction velocity (NCV) is a common measurement made during this test. (wikidoc.org)
  • The F-wave study evaluates conduction velocity of nerves between the limb and spine, whereas the motor and sensory nerve conduction studies evaluate conduction in the limb itself. (wikidoc.org)
  • Nociceptive pain, which is usually transient, arises from the activation of nociceptors-the sensory receptors by which a nerve impulse is triggered-by actual or threatened damaging stimuli. (reviewofoptometry.com)
  • 4 Neural impulses respond to stimuli at the ocular surface-most notably at the cornea, the most innervated area of the body-and then project information from external stimuli to the central nervous system. (reviewofoptometry.com)
  • It is the afferent activity produced in the peripheral and central nervous systems by stimuli that have the potential to damage tissue. (mhmedical.com)
  • Warm-fiber response to stimuli of 45°C or greater usually consisted of a short burst of impulses followed by cessation of activity. (johnshopkins.edu)
  • The somatic neural system relays impulses from the CNS to skeletal muscles. (edignite.com)
  • The autonomic neural system transmits impulses from the CNS to the involuntary organs and smooth muscles of the body. (edignite.com)
  • A neurone consists of a cell body (with a nucleus and cytoplasm), dendrites that carry electrical impulses to the cell, and a long axon that carries the impulses away from the cell. (medscape.com)
  • A sympathetic nerve to the heart that carries impulses that speed the heart rate. (unboundmedicine.com)
  • A neuron whose axon carries impulses away from the brain or spinal cord. (mhmedical.com)
  • Minimally, a recep- tor includes a peripheral axon terminal of one pri- mary afferent neuron, whose cell body is sited proximally in the dorsal root ganglion. (cdc.gov)
  • Furthermore, these results suggest that the probability of transmitter release at this synapse is regulated by either afferent activity and/or trophic communication with the target muscle. (jneurosci.org)
  • Short and long-term changes in synaptic efficacy occur in vivo at the central synapse between muscle spindle afferents (Ia) and spinal motoneurons ( Mendell, 1984 ). (jneurosci.org)
  • The compound action potential recording represents the summed activity of the individual axons and thus depends on the number of axons conducting, their relative sizes, and their conduction velocities. (evokedpotential.com)
  • Thus, due to amplitude differences and different conduction velocities, different fiber groups can be distinguished in our recordings. (evokedpotential.com)
  • The interpretation of nerve conduction studies is complex, but in general, different pathological processes result in changes in latencies, motor and/or sensory amplitudes, or slowing of the conduction velocities to differing degrees. (wikidoc.org)
  • HODGKIN AL, HUXLEY AF (1952) A quantitative description of membrane current and its application to conduction and excitation in nerve. (yale.edu)
  • The compound action potential is the propagated impulse in each axon and is an all or none even arising from the potential change across the cell membrane. (evokedpotential.com)
  • Generation of a nerve impulse (action potential) of a sensory neurone occurs as a result of a stimulus such as light, a particular chemical, or stretching of a cell membrane by sound. (medscape.com)
  • A sensory branch of the mandibular nerve (CN V3) It passes through the parotid gland en route to the ear, where it innervates skin of the pinna, external auditory canal, and tympanic membrane. (unboundmedicine.com)
  • In resting phase when the neuron is not conducting an impulse, the axonal membrane is called polarized. (edignite.com)
  • The electric potential difference across the plasma membrane at that site is called action potential, which in fact termed as the nerve impulse. (edignite.com)
  • Honmou O, Utzschneider DA, Rizzo MA, Bowe CM, Waxman SG, Kocsis JD (1994) Delayed depolarization and slow sodium currents in cutaneous afferents. (yale.edu)
  • Depolarization is very rapid, so that conduction of nerve impulse along the entire length of axon occurs in fractions of the second. (edignite.com)
  • The generation of a spinal nerve impulse from an external stimulus is called transduction. (reviewofoptometry.com)
  • The term peripheral nerve refers to the part of a spinal nerve distal to the root and plexus. (msdmanuals.com)
  • Pathways for ocular pain originate from a peripheral stimulus that then travels to the central nervous system along the afferent pathway. (reviewofoptometry.com)
  • This method uses an electrical stimulus with a neuroselective frequency to determine the minimum voltage causing conduction. (wikidoc.org)
  • Kajander KC, Wakisaka S, Bennett GJ (1992) Spontaneous discharge originates in the dorsal root ganglion at the onset of a painful peripheral neuropathy in the rat. (yale.edu)
  • Neurotoxicology Toxic neuropathy characterized by degeneration in the distal segments of large-diameter axons (dis- tal axonopathy) is a common morphological reaction 24 of the peripheral nervous system to exogenous toxins (2, 3). (cdc.gov)
  • On the other hand, slowing of all nerve conductions in more than one limb indicates generalized sick nerves, or generalized peripheral neuropathy . (wikidoc.org)
  • People with diabetes mellitus often develop generalized peripheral neuropathy. (wikidoc.org)
  • Specific modalities can be associated with unique peripheral receptors, peripheral axons of stereotyped diameter and specific central projection pathways. (cdc.gov)
  • This tone is ultimately controlled by impulses from the brain, though special receptors in the muscles themselves are also instrumental in its regulation. (humanneurobiology.com)
  • 4,5 The tips of the stromal nerves penetrate Bowman's layer, predominantly in the peripheral cornea, and give rise to long bundles that run from the periphery to the center close to the subbasal epithelia and resemble wavy lines. (reviewofoptometry.com)
  • These terms have a slightly different meaning in the context of the peripheral nervous system (PNS) and central nervous system (CNS). (wikipedia.org)
  • Nerves, whether peripheral or spinal, are made up of the axons traveling between the central nervous system and the peripheral end organ. (evokedpotential.com)
  • Environmental Health Perspectives Vol. 44, pp. 23-30, 1982 Structure and Function of the Somatosensory System: A Neurotoxicological Perspective by Joseph C. Arezzo*, Herbert H. Schaumburg* and Peter S. Spencer* The somatosensory system comprises those elements of the peripheral nervous system (PNS) and the central nervous system (CNS) subserving the modalities of touch, vibration, tempera- ture, pain and kinesthesia. (cdc.gov)
  • The anterior horn cells, although technically part of the central nervous system (CNS), are sometimes discussed with the peripheral nervous system because they are part of the motor unit. (msdmanuals.com)
  • It is distributed throughout the central and peripheral nervous systems. (medscape.com)
  • The peripheral nervous system allows for communication between the central nervous system and the rest of the body. (flashnews.net)
  • a neuron carrying nerve impulses to the central nervous system (brain and spinal cord) from the periphery (other parts of the body). (ashp.org)
  • Damage or dysfunction of peripheral nerves or the central nervous system (CNS) causes neuropathic pain. (diseasesdic.com)
  • Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. (lookformedical.com)
  • however, specific inputs (termed afferents) from other cells are received primarily on the surface of the cell body and on the surface of the specialized processes known as dendrites. (comoficar.com)
  • A nerve conduction study (NCS) is a test commonly used to evaluate the function, especially the ability of electrical conduction , of the motor and sensory nerves of the human body . (wikidoc.org)
  • they convey motor, touch, and proprioceptive impulses. (msdmanuals.com)
  • 3-5 Corneal epithelium-derived innervation from the subbasal nerve plexus has illustrated that the plexus forms a delicate three-dimensional network in the epithelium, originating from the branches of the peripheral stromal nerves. (reviewofoptometry.com)
  • The afferent signal travels across the sensory nerve to the relay synapses in the spinal cord, a process called conduction. (reviewofoptometry.com)
  • Although much is known about the activation of escape circuitry by the primary afferent inputs that signal approach of predators, such as acoustic,acousticolateralis, visual and mechanosensory inputs, far less is known about how the same circuits are engaged by abiotic stressors such as high or low temperature, or anoxia. (biologists.com)
  • The activation of peripheral primary afferent, gives rise to nociceptive sensation of pain. (diseasesdic.com)