myelin

noun

1. (countable, uncountable)A white, fatty material, composed of lipids and lipoproteins, that surrounds the axons of nerves.

   “As the result of prolonged action of water upon myelin, bird's-nests-cells are also said to be produced, and we are certain we have seen, as the result of such prolonged action of water, the appearances thus compared.”

   “This gene controls the production of an insulating sleeve that wraps around neurons. Known as myelin, it is crucial for long-range communication in the brain.”