Question: what glial cells produce myelin sheaths?
Answer: Depending on the location, different glial cell types make myelin in a different manner. Schwann cells make myelin in the peripheral nervous system (PNS: nerves) and oligodendrocytes in the central nervous system (CNS: brain and spinal cord). In the PNS, one Schwann cell forms a single myelin sheath (Figure 1A).