Wiktionary
n. (context neuroanatomy English) An envelope of myelin that surrounds nerve fibres.
WordNet
n. a layer of myelin encasing (and insulating) the axons of medullated nerve fibers [syn: medullary sheath]
Usage examples of "myelin sheath".
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.