In the human nervous system, which cell type forms myelin in the central nervous system?

An oligodendrocyte forms myelin around nerve fibers in the human central nervous system.

The central nervous system consists of the brain and spinal cord. Oligodendrocytes extend processes that wrap segments of their cell membranes around axons, creating myelin sheaths. Myelin electrically insulates axons and allows nerve impulses to travel rapidly by jumping between gaps called nodes of Ranvier.

Schwann cells perform the corresponding myelinating role in the peripheral nervous system, outside the brain and spinal cord. One oligodendrocyte can myelinate parts of several axons, whereas a Schwann cell typically myelinates one segment of one axon. Astrocytes support neurons and help regulate the neural environment, while microglia act as resident immune cells of the central nervous system.