myelin sheath

noun Anatomy.
  1. a wrapping of myelin around certain nerve axons, serving as an electrical insulator that speeds nerve impulses to muscles and other effectors.

Origin of myelin sheath

First recorded in 1895–1900
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

myelin sheath in Medicine

myelin sheath

n.
  1. The insulating envelope of myelin that surrounds the core of a nerve fiber or axon and that facilitates the transmission of nerve impulses, formed from the cell membrane of the Schwann cell in the peripheral nervous system and from oligodendroglia cells.medullary sheath
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