What is the main role of Schwann cells in the nervous system?

• A. Support synaptic transmission
• B. Produce myelin sheath in the CNS
• C. Produce myelin sheath in the PNS
• D. Regenerate damaged neurons

Answer: (C)

Schwann cells play a vital role in the peripheral nervous system (PNS) by producing the myelin sheath that insulates axons. This myelin sheath is essential for the efficient transmission of electrical impulses along the nerve fibers. By wrapping around the axons, Schwann cells increase the speed of action potentials through a process known as saltatory conduction, where the action potential jumps between the nodes of Ranvier (the gaps in the myelin sheath).

In contrast, the production of myelin sheath in the central nervous system (CNS) is carried out by oligodendrocytes, not Schwann cells. While Schwann cells can also assist in the regeneration of damaged peripheral nerves, their primary function remains the formation of myelin sheaths in the PNS. Therefore, the correct answer highlights Schwann cells' crucial role in myelination within the specific context of the peripheral nervous system.