If an axon is myelinated it means that it is surrounded by a myelin sheath, which acts as an electrical insulator. Myelin can be formed by glial cells and depending on the location of the axon, these cells differ in type. In the central nervous system axons are myelinated by oligodendrocytes and in the peripheral nervous system axons are myelinated by schwann cells. Myelination speeds up the rate of transmission of an action potential by a process called saltatory conduction. The action potential is propagated (jumps) between the regular gaps in the myelin sheath, known as Nodes of Ranvier .
- ↑ Alberts, B., Johnson, A., Lewis, J,. Raff, M., Roberts, K., and Walter, P., 2008. Molecular Biology of the Cell, 5th ed. New York: Garland Science.