A nerve is an enclosed, cable-like bundle of axons (the long, slender projections of neurons) in the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons to peripheral organs.
In the central nervous system, the analogous structures are known as tracts. Neurons are sometimes called nerve cells, though this term is potentially misleading since many neurons do not form nerves, and nerves also include non-neuronal Schwann cells that coat the axons in myelin.
Each nerve is a cordlike structure that contains many axons. These axons are often referred to as "fibres". Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium. The axons are bundled together into groups called fascicles, and each fascicle is wrapped in a layer of connective tissue called the perineurium. Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium.
Famous quotes containing the word nerve:
“There must be some nerve and heroism in our love, as of a winter morning.”
—Henry David Thoreau (18171862)
“Tom: All right, boys. Cmon. Why dont you say Im a yellow belly and a big mouth at that?
Shep: You yellow? Who thinks youre yellow? Did you hear what he said? A guy whos got the nerve to marry? Thats more than Flash Gordon ever did.”
—Billy Wilder (b. 1906)
“The American people is out to get the kaiser. We are bending every nerve and every energy towards that end; anybody who gets in the way of the great machine the energy and devotion of a hundred million patriots is building towards the stainless purpose of saving civilization from the Huns will be mashed like a fly. Im surprised that a collegebred man like you hasnt more sense. Dont monkey with the buzzsaw.”
—John Dos Passos (18961970)