nerve

(redirected from nerves)
Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Idioms, Wikipedia.
Related to nerves: anxiety, Cranial nerves, sciatic nerve

nerve:

see nervous systemnervous system,
network of specialized tissue that controls actions and reactions of the body and its adjustment to the environment. Virtually all members of the animal kingdom have at least a rudimentary nervous system.
..... Click the link for more information.
.

Nerve

 

the cordlike association of nerve tissues that links the brain and nerve ganglia by innervation to the other organs and tissues of the body.

A nerve primarily consists of nerve fibers. In vertebrates many nerves converge to form a bundle that is surrounded by a connective tissue sheath, the perineurium; the thin interstitial layers of connective tissue that separate the individual fibers deep within the bundle constitute the endoneurium. Finally, the entire nerve trunk, comprising several bundles, is covered by an additional sheath, the epineurium.

Nerves can be sensory (also called afferent or centripetal) or motor (also called efferent or centrifugal). Some nerves, for example, those innervating the skeletal muscles, mainly include myelinated, or medullated, fibers; others, for example, the sympathetic nerves, largely consist of unmyelinated, or unmedullated, fibers.

In reptiles, birds, mammals, and man 12 pairs of cranial nerves branch from the brain: the olfactory (cranial nerve I), the optic (cranial nerve II), the oculomotor (cranial nerve III), the trochlear (cranial nerve IV), the trigeminal (cranial nerve V), the abducent (cranial nerve VI), the facial (cranial nerve VII), the acoustic (cranial nerve VIII), the glossopharyngeal (cranial nerve IX), the vagus (cranial nerve X), the accessory (cranial nerve XI), and the hypoglossal (cranial nerve XII). Only the first ten pairs are present in fish and amphibians.

In man there are 31 pairs of spinal nerves: eight cervical, 12 thoracic, five lumbar, five sacral, and one coccygeal. Each pair innervates the effectors and receptors of a certain part of the body. The spinal nerves branch from the spinal cord into two roots—the posterior, or sensory, and the anterior, or motor. Both roots then combine to form a common trunk that consists of both sensory and motor fibers.

Several adjacent nerves can be combined into nerve plexuses, where an exchange of fibers between different nerves can take place. Three large plexuses are distinguished: the cervical, the brachial, and the lumbosacral. Each nerve plexus is the origin of several pairs of nerves; for example, the sacral portion of the lumbosacral plexus gives rise to the sciatic nerves.

Nerves that originate in the ganglia, trunks, and plexuses of the autonomic nervous system constitute a specific group. The optic nerve is remarkable for its large number of fibers; there are more than 1 million in the human optic nerve. Usually, however, there are 103 -104 fibers in a nerve. In invertebrates certain nerves are known to consist of only a few fibers. The peripheral nervous system in animals and man consists of aggregations of nerves.

D. A. SAKHAROV

nerve

[nərv]
(neuroscience)
A bundle of nerve fibers or processes held together by connective tissue.

nervure

Any one of the ribs of a groined vault, but esp. a rib which forms one of the sides of a compartment of the groining.

nerve

1. any of the cordlike bundles of fibres that conduct sensory or motor impulses between the brain or spinal cord and another part of the body
2. a large vein in a leaf
3. any of the veins of an insect's wing
References in classic literature ?
Still I quivered in every nerve to think how slight a sinking of the machinery would precipitate that keen, glistening axe upon my bosom.
So paralyzed were we by the apparition that we allowed him to pass before we had recovered our nerve.
To Jane the strange apparition of this god-like man was as wine to sick nerves.
Their long arms, their short and crooked legs, their close-set, evil eyes, and their low, receding foreheads gave them a bestial appearance that sent a qualm of paralyzing fright through the shaken nerves of the Belgian.
Again and again she would start and turn to peer into the blackness beyond the trees behind her as her overwrought nerves conjured the stealthy fall of padded feet.
Von Horn admired her nerve though he rather wished that she would ask some questions--it was difficult making progress in this way.
You appear to be so well acquainted with the favorable opinion which Miss Alicia and I entertain of each other, that I hope it will be no fresh shock to your nerves, if I inform you, in plain words, that I have come to Crickgelly to marry her.
But there was little sleep in camp that night until utter exhaustion overtook the harassed men toward morning; nor was there any return of the weird creature that had set the nerves of each of them on edge.
He, who was more delicately coordinated, more finely nerved and strung than any of them, had no nerves of this sort.
And it seemed to me that his eyes were strange, not only the expression, but the physical seeming, as though the optic nerves and supporting muscles had suffered strain and slightly twisted the eyeballs.
He was a man in perfect health, ignorant of the meaning of nerves, a man of proved courage.
I should think he'd be glad that if he did have the nerves he'd got money, too; shouldn't you?