The protective covering around nerve cells.
A layer of myelin that insulates some nerve cells and speeds the conduction of nerve impulses.
Segmented, fatty covering composed of myelin that covers the axons of some nerve fibers.
A fatty substance surrounding some neurons that acts as an electrical insulator, increasing the speed of nerve impulse transmission.
Layers of the cell membrane of Schwann cells (peripheral nervous system) or oligodendrocytes (central nervous system) that wrap nerve fibers, providing electrical insulation and increasing the velocity of impulse transmission.