nerve

A nerve is a nerve cell or string of them that are used for the biological purpose of sensing stimulus and internal bodily conditions. Used in expressions such as "get on my nerves" and "strike a nerve" to denote irritation.

Edmund S. Crelin, PhD, professor of Anatomy at the Yale University School of Medicine, testified that:

Nerves do not give off a flow of energy. Nerves are gland cells. They produce and release a hormone that causes the inhibition or the contraction of muscle cells and the inhibition or enhancement of secretion by a gland cell that includes another nerve cell. That is all they do, no more, no less. They do not actually conduct electricity or any other form of energy.

When a nerve cell undergoes its function of secreting a hormone, changes occur in its outer cell membrane that allow electrically-charged ions to move in and out of the cell in a step-wise fashion along the full extent of the nerve. This is what really occurs when a nerve is described as "conducting an impulse" or "firing." A spinal nerve at the intervertebral opening is actually a thin tube of connective tissue containing the extensions of millions of nerve cells. These extensions are the axons that are also described as "fibers." This latter term is misleading because it connotes a certain firmness such as fine wires would have. Nothing could be more incorrect. The axons are delicate, flimsy structures. Since they are merely elongated or drawn out parts of cells they need nourishment along with the cells that make up their sheaths. Therefore, delicate blood vessels are contained in what is called a nerve at the visible level. If compression of a nerve does not directly kill the axons, the axons may die because the compression cuts off the flow of blood in the vessels of the nerve. Compression of a nerve cell anywhere along its extent can cause it to secrete its hormone. If it is a sensory nerve cell, it can cause the brain to experience pain. If it is a motor nerve cell, the hormone can cause a muscle cell to contract.

If the motor nerve cells to a skeletal (voluntary) muscle die, the muscle will be paralyzed and also die. This is because the motor nerve cells continuously supply skeletal muscle cells with substances needed for their survival, above and beyond the hormone the nerve cells secrete to make the muscle contract. This is not the case with the motor nerve cells to glands, heart muscle, or smooth (involuntary) muscle. Complete severance of the motor nerves from the spinal nerves to the heart, glands (salivary, thyroid, liver, pancreas, etc.), and smooth muscle of the lungs, esophagus, stomach, gall bladder, intestines, etc., has only transient effects. The gland cells and smooth and cardiac muscle cells not only survive, but function normally. They surely do not become diseased.

This was in response to a Pennsylvania chiropractor's claim that pinched nerves caused a reduction in the flow of "nerve energy" to some part of the body, with detrimental effects to that part of the body's health.

Nerve (?), n. [OE. nerfe, F. nerf, L. nervus, akin to Gr. sinew, nerve; cf. string, bowstring; perh. akin to E. needle. Cf. Neuralgia.]

1. Anat.

One of the whitish and elastic bundles of fibers, with the accompanying tissues, which transmit nervous impulses between nerve centers and various parts of the animal body.

⇒ An ordinary nerve is made up of several bundles of nerve fibers, each bundle inclosed in a special sheath (the perineurium) and all bound together in a connective tissue sheath and framework (the epineurium) containing blood vessels and lymphatics.

2.

A sinew or a tendon.

Pope.

3.

Physical force or steadiness; muscular power and control; constitutional vigor.

he led me on to mightiest deeds, Above the nerve of mortal arm. Milton.

4.

Steadiness and firmness of mind; self-command in personal danger, or under suffering; unshaken courage and endurance; coolness; pluck; resolution.

5.

Audacity; assurance.

6. Bot.

One of the principal fibrovascular bundles or ribs of a leaf, especially when these extend straight from the base or the midrib of the leaf.

7. Zool.

One of the nervures, or veins, in the wings of insects.

Nerve cell Anat., one of the nucleated cells with which nerve fibers are connected; a ganglion cell.<-- = neuron, a word listed only in a different sens in W1913 --> -- Nerve fiber Anat., one of the fibers of which nerves are made up. These fibers are either medullated or nonmedullated. in both kinds the essential part is the translucent threadlike axis cylinder which is continuous the whole length of the fiber. -- Nerve stretching Med., the operation of stretching a nerve in order to remedy diseases such as tetanus, which are supposed to be influenced by the condition of the nerve or its connections.<-- #!? -->

© Webster 1913.

Nerve (?), v. t. [imp. & p. p. Nerved (?); p. pr. & vb. n. Nerving.]

To give strength or vigor to; to supply with force; as, fear nerved his arm.

© Webster 1913.