myelin

American  

[mahy-uh-lin] / ˈmaɪ ə lɪn /

Also myeline

noun

Biology.

1. a soft, white, fatty material in the membrane of Schwann cells and certain neuroglial cells: the substance of the myelin sheath.

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myelin British  

/ ˈmaɪɪˌliːn, ˈmaɪɪlɪn /

noun

1. a white tissue forming an insulating sheath ( myelin sheath ) around certain nerve fibres. Damage to the myelin sheath causes neurological disease, as in multiple sclerosis

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myelin Scientific  

/ mī′ə-lĭn /

1. A whitish, fatty substance that forms a sheath around many vertebrate nerve fibers. Myelin insulates the nerves and permits the rapid transmission of nerve impulses. The white matter of the brain is composed of nerve fibers covered in myelin.

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Other Word Forms

• myelinic
  adjective

Etymology

Origin of myelin

First recorded in 1865–70; myel- + -in ²

Example Sentences

Myelin is the protective sheath covering each nerve cell's axon -- the threadlike portion of a cell that transmits electrical signals between cells.

From Science Daily • Jan. 14, 2024

Myelin acts as an insulator that prevents current from leaving the axon; this increases the speed of action potential conduction.

From Textbooks • Jun. 9, 2022

Over 10 years, first for the Myelin Repair Foundation and then for the MS Society, he has made six tandem sky-diving jumps.

From New York Times • Jan. 14, 2022

Myelin, long considered inert insulation on axons, is now seen as making a contribution to learning by controlling the speed at which signals travel along neural wiring.

From Scientific American • Mar. 12, 2020

Myelin is often likened to the plastic coating around electrical wires—it insulates the neural circuits, making them about a hundred times faster than unmyelinated circuits.

From "The 57 Bus" by Dashka Slater