from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The protein component of the myelin sheath
from the GNU version of the Collaborative International Dictionary of English
- n. A substance, resembling keratin, present in nerve tissue, as in the sheath of the axis cylinder of medullated nerve fibers. Like keratin it resists the action of most chemical agents, and by decomposition with sulphuric acid yields leucin and tyrosin.
from The Century Dictionary and Cyclopedia
- n. A substance allied to ceratin.
Sorry, no etymologies found.
The axis-cylinder is said by some to be enveloped in a special reticular sheath, which separates it from the medullary sheath, and is composed of a substance called neurokeratin.