ABSTRACT
The myelin sheath in the central nervous system is composed of multiple layers of oligodendrocyte cell membrane wrapped around the axon. The myelin sheath of a single axon is divided by nodes of Ranvier into short segments (internodal segments). A single oligodendrocyte provides an internodal segment of myelin to several axons in its vicinity. The function of myelin is to provide electrical insulation of the cell membrane of the axon so that the ion fluxes across the axon membrane, resulting in the action potential, take place only at the nodes of Ranvier. As a consequence, the action potential jumps from node to node (saltatory conduction) providing rapid transmission of the electrical impulse along the axon.
