Which structure forms the insulating layer around many peripheral axons?

Which structure forms the insulating layer around many peripheral axons?

• A. Schwann cell
• B. Cytoplasm
• C. Myelin sheath
• D. Node of Ranvier

Answer: (C)

The insulating layer around peripheral axons is the myelin sheath. In the peripheral nervous system, Schwann cells wrap around an axon, laying down many layers of membrane to form this sheath. That multilayer insulation increases membrane resistance and lowers capacitance, so electrical impulses jump quickly from one node of Ranvier to the next (saltatory conduction). The nodes themselves are gaps between myelin segments and are not the insulating layer, while cytoplasm is just the inside fluid of the cell.

The insulating layer around peripheral axons is the myelin sheath. In the peripheral nervous system, Schwann cells wrap around an axon, laying down many layers of membrane to form this sheath. That multilayer insulation increases membrane resistance and lowers capacitance, so electrical impulses jump quickly from one node of Ranvier to the next (saltatory conduction). The nodes themselves are gaps between myelin segments and are not the insulating layer, while cytoplasm is just the inside fluid of the cell.