Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Myelin is a fatty substance that forms an insulating sheath around the axons of many neurons. It increases the speed at which electrical impulses propagate along the nerve cells.
5 Must Know Facts For Your Next Test
Myelin is produced by oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system.
The myelin sheath is interrupted at intervals by nodes of Ranvier, which facilitate rapid conduction of nerve impulses.
Demyelination can lead to neurological disorders such as multiple sclerosis.
Myelination begins during fetal development and continues into young adulthood.
The primary function of myelin is to increase the speed and efficiency of electrical signal transmission in neurons.
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Related terms
Neuron: A neuron is a nerve cell that transmits electrical and chemical signals throughout the body.
Oligodendrocyte: An oligodendrocyte is a type of glial cell in the central nervous system responsible for producing myelin.
Schwann Cell: A Schwann Cell is a type of glial cell in the peripheral nervous system that produces myelin.