What type of cells are the primary myelin-forming cells in the peripheral nervous system?

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

Answer: (C)

Schwann cells are the primary myelin-forming cells in the peripheral nervous system (PNS). Their main function is to wrap around the axons of peripheral neurons, forming the myelin sheath that insulates the axon and enhances the speed of electrical signal transmission. Each Schwann cell can myelinate a single segment of an axon, allowing for efficient conduction of nerve impulses.

In addition to myelination, Schwann cells play a role in the regeneration and repair of peripheral nerves after injury. When a nerve is damaged, these cells help facilitate the regrowth of axons and support the healing process by creating a favorable environment for regeneration.

Other cell types mentioned, such as microglia and astrocytes, have different roles in the nervous system. Microglia serve as the immune cells of the central nervous system (CNS), responsible for removing debris and responding to injury. Astrocytes are involved in supporting neuronal function, maintaining the blood-brain barrier, and regulating the extracellular environment. Oligodendrocytes, unlike Schwann cells, are the myelin-forming cells in the central nervous system, myelinating multiple axons at once.

Thus, Schwann cells are central to the myelination process