myelin sheath

American  

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.

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Etymology

Origin of myelin sheath

First recorded in 1895–1900

Example Sentences

MS is a disease of the brain and central nervous system, in which the immune system mistakenly attacks the fatty myelin sheath that normally protects the nerves, like insulation around electric wires.

From BBC • May 29, 2026

These metabolites support the growth and maturation of oligodendrocytes, which in turn helps rebuild the myelin sheath.

From Science Daily • Apr. 15, 2026

Demyelination is the process in which the myelin sheath -- a protective, insulating layer surrounding nerve fibers in the brain and spinal cord -- is damaged or destroyed.

From Science Daily • Jan. 6, 2026

Although existing treatments can help reduce inflammation, there are still no approved therapies that protect neurons or rebuild the damaged myelin sheath.

From Science Daily • Oct. 11, 2025

"There may be a way to intervene so that you can increase the myelin sheath," he said.

From Science Daily • Jan. 14, 2024