Myelin

Myelinan electrically insulating fatty layer that surroundsaxonsmany neurons, especially those inperipheral nervous system. Itan outgrowthglial cells: Schwann cells supplymyelinperipheral neurons while oligodendrocytes supply itthose ofcentral nervous system.

The main consequence ofmyelin layer (or sheath)an increase inspeed at which impulses propagate alongmyelinated fiber. Along unmyelinated fibers impulses move continuously as waves, butmyelinated fibershop (or "propagate by saltation"). Whenfibersevered,myelin sheath providestrack along which regrowth can occur. Unmyelinated fibers do not regenerate.

Demyelination islossmyelinisroot causesymptoms experienced by patientsdiseases such as multiple sclerosistransverse myelitis. When an axon's myelin degrades duethese diseases, conduction can be impaired or lost.\n