Myelin

Myelin is the sheath of fatty protein which surrounds the axon of a neuron. Myelin considerably increases the speed of the nerve signals which move down the axons. Myelin is produced by glial cells such as Oligodendrocytes and Schwann cells.

Myelin gives axons the white appearance, thus the "white matter" of the brain. Myelin is composed of about 80% lipid and about 20% protein. Some of the proteins that make up myelin are Myelin basic protein, Myelin oligodendrocyte glycoprotein, and Proteolipid protein.