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

See Examples For:

myelin sheath

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

Oligodendrocytes, the cells that produce myelin to insulate nerve fibers, expressed fewer genes required for maintaining and regenerating the myelin sheath.

From Science Daily ● Nov. 24, 2025

In MS, the immune system mistakenly attacks the myelin sheath, a protective layer that insulates nerve fibers.

From Science Daily ● Oct. 11, 2025

In the brain, oligodendrocytes wrap around the long, skinny connections between nerve cells known as axons, where they produce a lipid membrane called a myelin sheath that coats the axon.

From Science Daily ● Mar. 28, 2024

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

From Science Daily ● Jan. 14, 2024