Which cell forms the myelin sheath in the peripheral nervous system?

Which cell forms the myelin sheath in the peripheral nervous system?

• A. Perineurium
• B. Schwann cell
• C. Satellite cell
• D. Neuron

Answer: (B)

In the peripheral nervous system, the myelin sheath around axons is produced by Schwann cells. These glial cells wrap their membranes around a single axon segment, laying down multiple layers to insulate the axon. That insulation speeds up electrical signaling through saltatory conduction, allowing impulses to jump from one node of Ranvier to the next. Schwann cells also play a role in guiding axon regeneration after injury in the PNS. Perineurium surrounds a nerve fascicle, providing protection but not forming myelin. Satellite cells support neuron cell bodies in ganglia, maintaining the local environment. Neurons are the signaling cells themselves and do not create the myelin sheath. For completeness, in the CNS, oligodendrocytes perform the myelination, typically wrapping multiple axons.

In the peripheral nervous system, the myelin sheath around axons is produced by Schwann cells. These glial cells wrap their membranes around a single axon segment, laying down multiple layers to insulate the axon. That insulation speeds up electrical signaling through saltatory conduction, allowing impulses to jump from one node of Ranvier to the next. Schwann cells also play a role in guiding axon regeneration after injury in the PNS.

Perineurium surrounds a nerve fascicle, providing protection but not forming myelin. Satellite cells support neuron cell bodies in ganglia, maintaining the local environment. Neurons are the signaling cells themselves and do not create the myelin sheath. For completeness, in the CNS, oligodendrocytes perform the myelination, typically wrapping multiple axons.