Find the word definition

Crossword clues for myelin

The Collaborative International Dictionary

myelin \my"e*lin\, myeline \my"e*line\, n. [Gr. myelo`s marrow.] (Physiol. Chem.)

  1. A soft white substance constituting the medullary sheaths of nerve fibers, and composed mainly of cholesterin, lecithin, cerebrin, protein, and some fat.

  2. One of a group of phosphorized principles occurring in nerve tissue, both in the brain and nerve fibers.

Douglas Harper's Etymology Dictionary

also myeline, "soft material found in nerve tissues," 1867, from German Myelin (1854), from Greek myelos "marrow; the brain, innermost part," of unknown origin.


n. (context neuroanatomy English) A white, fatty material, composed of lipids and lipoproteins, that surrounds the axons of nerves.


n. a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers [syn: myeline, medulla]


Myelin is a fatty white substance that surrounds the axon of some nerve cells, forming an electrically insulating layer. It is essential for the proper functioning of the nervous system. It is an outgrowth of a type of glial cell.

The production of the myelin sheath is called myelination or myelinogenesis. In humans, myelination begins early in the 3rd trimester, although little myelin exists in the brain at the time of birth. During infancy, myelination occurs quickly, leading to a child's fast development, including crawling and walking in the first year. Myelination continues through the adolescent stage of life.

Schwann cells supply the myelin for the peripheral nervous system, whereas oligodendrocytes, specifically of the interfascicular type, myelinate the axons of the central nervous system. Myelin is considered a defining characteristic of the (gnathostome) vertebrates, but myelin-like sheaths have also been seen in some invertebrates, although they are quite different from vertebrate myelin at the molecular level. Myelin was discovered in 1854 by Rudolf Virchow.

Usage examples of "myelin".

The axon is like a thin line running down the axis of the interrupted cylinder formed by the myelin sheath.

Jase by this time was taking a daily handful of pills: myelin enhancers to slow the loss of nerve tissue, neurological boosters to help the brain rewire damaged areas, and secondary medication to treat the side effects of the primary medication.

Genetic engineering solved this problem: scientists could synthesize the genes that code for the production of myelin toxin, reproduce them artificially in the lab, and insert them into bacterial cells.

If a bacterial strain compatible with myelin toxin could be found, the transplanted genes would multiply along with the bacteria.

This receives its name because demyelination occurs in many patches, spread out over the body, the soft myelin being replaced by a scar of harder fibrous tissue.

Such demyelination may come about through the effect on the myelin of a protein in the patient's blood.

The little matter of myelin sheathing,6 since it had already been disproven by laboratory research which included the reaching of birth, was discarded.

The fatty myelin sheath of these fibers lend the interior of the cerebrum a whitish appearance, and this is the white matter of the brain.

A trunch, used at full load, will strip the myelin sheath from axons and dendrites.

What's more, the axon is insulated by a thick myelin sheath, so that the wave energy will not be lost to the outside, but will be kept tightly within the axon.

The myelin sheath of the nerve fibers develops hard patches and this eventually results in permanent paralysis.

Above, he thought, the myelin sheath of nerve fibers which had developed the sclerotic patches which were killing her.

More frightening, alien terms such as leukodystrophy and DNA mutation and myelin sheath were mentioned to the parents during this tensely wailful period.

Even nerves without myelin sheaths have axons that are surrounded by layers of small Schwann's cells with, of course, nuclei.

Axons had been splayed open in many places, the myelin sheaths broken and disrupted, destroying the axon'.