Myelin

Myelin is a lipid-rich insulating sheath around many nerve fibers. It speeds electrical signal transmission and supports the axons it surrounds.

Saltatory conduction: Rapid nerve impulse propagation in myelinated axons, with action potentials regenerated at gaps between myelin segments. Myelin confines regenerative electrical activity to exposed gaps, making impulses appear to leap along the axon.
Oligodendrocyte: A central nervous system glial cell that forms myelin around segments of multiple axons. Oligodendrocytes produce myelin in the brain and spinal cord.
Multiple sclerosis: An immune-mediated disease in which damage to central nervous system myelin disrupts neural function. Inflammatory injury to myelin is a defining feature of this disease.
Unmyelinated nerve fiber: A nerve fiber that lacks a multilayered myelin sheath. Without myelin insulation, electrical signals propagate differently and generally more slowly.
Node of Ranvier: A short exposed gap between adjacent myelin segments along a nerve fiber. Voltage-gated ion channels concentrated at these gaps regenerate action potentials.
Schwann cell: A peripheral nervous system glial cell that forms myelin around one segment of one axon. Schwann cells produce myelin outside the brain and spinal cord.
Guillain–Barré syndrome: A group of acute immune-mediated peripheral nerve disorders that can cause weakness and sensory symptoms. Several forms involve immune injury to peripheral nerve myelin.
Conduction velocity: The speed at which an electrical impulse travels along a nerve fiber. Myelin is one major determinant of how quickly signals travel along axons.
Internode: The myelinated portion of an axon between two successive nodes of Ranvier. Each internode provides the insulated stretch that allows current to travel rapidly toward the next node.
Myelin basic protein: A major structural protein of central nervous system myelin that helps compact its membrane layers. Its abundance and structural role help stabilize central nervous system myelin.

Linked from 28 pages