Medical Definition of Myelin

Myelin: The fatty substance that covers and protects nerves. Myelin is a layered tissue that surrounds the nerve fibers (axons). This sheath around the axons acts like a conduit in an electrical system, ensuring that messages sent by axons are not lost en route.

Quick GuideDementia, Alzheimer's Disease, and Aging Brains

Dementia, Alzheimer's Disease, and Aging Brains

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Last Editorial Review: 5/13/2016

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