Definition of Myelin

Myelin: The fatty substance that covers and protects nerves. Myelin is a layered tissue that sheathes the axons (nerve fibers). This sheath around the axon acts like a conduit in an electrical system, ensuring that messages sent by axons are not lost en route. It allows efficient conduction of action potentials down the axon. Myelin consists of 70% lipids (cholesterol and phospholipid) and 30% proteins. It is produced by oligodendrocytes in the central nervous system.