Which glial cells form the myelin sheath in the peripheral nervous system?

Which glial cells form the myelin sheath in the peripheral nervous system?

• A. Oligodendrocytes
• B. Schwann cells
• C. Astrocytes
• D. Microglia

Answer: (B)

Peripheral nervous system myelination is done by Schwann cells. These glial cells wrap around a single segment of an axon to form the myelin sheath, creating gaps called nodes of Ranvier that enable rapid signal transmission via saltatory conduction. In the CNS, oligodendrocytes handle myelination, with each oligodendrocyte extending multiple processes to insulate several axons. Astrocytes and microglia have other roles—astrocytes support metabolism and the blood–brain barrier, while microglia act as immune cells within the CNS. So, for the PNS, Schwann cells are the myelin-forming glia.

Peripheral nervous system myelination is done by Schwann cells. These glial cells wrap around a single segment of an axon to form the myelin sheath, creating gaps called nodes of Ranvier that enable rapid signal transmission via saltatory conduction. In the CNS, oligodendrocytes handle myelination, with each oligodendrocyte extending multiple processes to insulate several axons. Astrocytes and microglia have other roles—astrocytes support metabolism and the blood–brain barrier, while microglia act as immune cells within the CNS. So, for the PNS, Schwann cells are the myelin-forming glia.