afferent nerve

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Related to afferent nerve: afferent neuron, Afferent fibers, afferent pathway


a macroscopic cordlike structure of the body, comprising a collection of nerve fibers that convey impulses between a part of the central nervous system and some other body region. See Appendix 2-6 and see color plates.

Depending on their function, nerves are known as sensory, motor, or mixed. Sensory nerves, sometimes called afferent nerves, carry information from the outside world, such as sensations of heat, cold, and pain, to the brain and spinal cord. Motor nerves, or efferent nerves, transmit impulses from the brain and spinal cord to the muscles. Mixed nerves are composed of both motor and sensory fibers, and transmit messages in both directions at once.

Together, the nerves make up the peripheral nervous system, as distinguished from the central nervous system (brain and spinal cord). There are 12 pairs of cranial nerves, which carry messages to and from the brain. Spinal nerves arise from the spinal cord and pass out between the vertebrae; there are 31 pairs, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. The various nerve fibers and cells that make up the autonomic nervous system innervate the glands, heart, blood vessels, and involuntary muscles of the internal organs.
Details of structure of components of nerve tissue.
accelerator n's the cardiac sympathetic nerves, which, when stimulated, accelerate the action of the heart.
acoustic nerve vestibulocochlear nerve; see anatomic Table of Nerves in the Appendices.
afferent nerve any nerve that transmits impulses from the periphery toward the central nervous system, such as a sensory nerve. See also neuron.
articular nerve any mixed peripheral nerve that supplies a joint and its associated structures.
auditory nerve vestibulocochlear nerve; see anatomic Table of Nerves in the Appendices.
autonomic nerve any nerve of the autonomic nervous system; called also visceral nerve.
cranial n's see cranial nerves.
cutaneous nerve any mixed peripheral nerve that supplies a region of the skin. See anatomic Table of Nerves in the Appendices.
depressor nerve
1. a nerve that lessens the activity of an organ.
2. an afferent nerve whose stimulation causes a fall in blood pressure.
efferent nerve any nerve that carries impulses from the central nervous system toward the periphery, such as a motor nerve. See also neuron.
excitor nerve one that transmits impulses resulting in an increase in functional activity.
excitoreflex nerve a visceral nerve that produces reflex action.
fusimotor n's those that innervate the intrafusal fibers of the muscle spindle.
gangliated nerve any nerve of the sympathetic nervous system.
inhibitory nerve one that transmits impulses resulting in a decrease in functional activity.
medullated nerve myelinated nerve.
mixed nerve (nerve of mixed fibers) a nerve composed of both sensory (afferent) and motor (efferent) fibers.
motor nerve a peripheral efferent nerve that stimulates muscle contraction.
myelinated nerve one whose axons are encased in a myelin sheath; called also medullated nerve.
peripheral nerve any nerve outside the central nervous system.
pilomotor n's those that supply the arrector muscles of hair.
pressor nerve an afferent nerve whose irritation stimulates a vasomotor center and increases intravascular tension.
sciatic nerve see sciatic nerve.
secretory nerve an efferent nerve whose stimulation increases vascular activity.
sensory nerve a peripheral nerve that conducts impulses from a sense organ to the spinal cord or brain. See also neuron.
somatic n's the sensory and motor nerves supplying skeletal muscle and somatic tissues.
spinal n's the 31 pairs of nerves arising from the spinal cord and passing out through the vertebrae; there are eight cervical, twelve thoracic, five lumbar, five sacral, and one coccygeal. , and see anatomic Table of Nerves in the Appendices.
Spinal nerves emerging from the spinal cord through the intervertebral foramina with muscles or muscle movements listed for specific levels. From McQuillan et al., 2002.
splanchnic n's those of the blood vessels and viscera, especially the visceral branches of the thoracic, abdominal (lumbar), and pelvic parts of the sympathetic trunks. See Appendix 3-5.
sudomotor n's those that innervate the sweat glands.
sympathetic n's
2. any nerve of the sympathetic nervous system.
trophic nerve one concerned with regulation of nutrition.
unmyelinated nerve one whose axons are not encased in a myelin sheath.
vasoconstrictor nerve one whose stimulation causes contraction of blood vessels.
vasodilator nerve one whose stimulation causes dilation of blood vessels.
vasomotor nerve one concerned in controlling the caliber of vessels, whether as a vasoconstrictor or vasodilator.
vasosensory nerve any nerve supplying sensory fibers to the vessels.
visceral nerve autonomic nerve.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

af·fer·ent nerve

a nerve conveying impulses from the periphery to the central nervous system.
Farlex Partner Medical Dictionary © Farlex 2012

Afferent Nerve

A nerve (e.g., a sensory nerve) which transmits impulses from peripheral afferent (sensory, receptor) neurones in sensory tissue to the spinal cord and brain.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

af·fer·ent nerve

(af'ĕr-ĕnt nĕrv)
A nerve conveying impulses from the periphery to the central nervous system.
Synonym(s): centripetal nerve.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

af·fer·ent nerve

(af'ĕr-ĕnt nĕrv)
Nerve conveying impulses from the periphery to the central nervous system.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
It converges visceral afferent nerves from the periphery, descending projection nerves from the senior center, and SDH neurons, thus forming a complex neural network.
These data may indicate that the afferent nerve system of the tactile sensation was preserved even though thermal sensation was impaired.
In addition BTX-A appears to have an effect by modulating the release of adenosine triphosphate (ATP) from urothelium the effect being seen on afferent nerve activity.
An evoked potential occurs when the stimulation of sensory receptors or afferent nerve bundles past their resting threshold results in the generation of a compound action potential.
We report here the operational voltage range of an isolated organ based on the afferent nerve activity for small voltage (microvolt) clamps of the ampullary epithelium and the stimulus amplitude range for a linear response of the ampullary epithelium.
In tension-type headache (TTH), central mechanisms are the major factors.1,2 Blink reflex (BR) is an objective neurophysiologic assessment method for trigeminal system, facial nerve and lateral medulla status.3,4 Afferent arc of BR is formed by the sensation fibers of trigeminal nerve while efferent arc is formed by motor nerve fibers.5-8 BR occurs with electrical or mechanical stimulation of supraorbital nerve and includes three responses: Early response is the ipsilateral response to the stimulation (R1), and two late responses are the ipsilateral and contra lateral responses (R2i and R2k).9 R1 is a cutaneous originated oligosynaptic reflex, which is transported by trigeminal afferent nerve fibers.
We now know that inserting needles into the skin and manipulating them or using high- or low-intensity electrical stimulation results in a number of physiologic events: stimulation of small myelinated type II and III afferent nerve fibers; release of beta-endorphins and neurotransmitters such as serotonin and substance P; and activation of the dorsal horn nuclei at the spinal cord level, the brain stem level, and the hypothalamic-pituitary level.
Picker to examine the neurophysiologic effects of spinal manipulation showed that there is an impact of spinal manipulation on primary afferent nerves from paraspinal tissues, the motor control system and pain processing.
TRPA1 presents on afferent nerves, which can detect and react to potentially damage, such as stress, physical and chemical stimuli.
[23,24] In addition, the peripheral terminals of primary afferent nerves innervating somatic tissues also express NMDA receptors.
Pan, "Role of primary afferent nerves in allodynia caused by diabetic neuropathy in rats," Neuroscience, vol.