Which type of ion channels are highly concentrated in the nodes of Ranvier?

• A. Calcium channels
• B. Ligand-gated potassium channels
• C. Chloride channels
• D. Voltage-gated sodium channels

Answer: (D)

Verified step by step guidance

1. Understand the function of the nodes of Ranvier: These are gaps in the myelin sheath of axons that facilitate rapid conduction of nerve impulses.
2. Recognize the role of ion channels in nerve impulse transmission: Ion channels allow ions to move across the neuronal membrane, which is crucial for generating action potentials.
3. Identify the specific ion channels involved in action potential propagation: Voltage-gated sodium channels are essential for the depolarization phase of the action potential.
4. Consider the location of these channels: Voltage-gated sodium channels are highly concentrated at the nodes of Ranvier to enable the rapid influx of sodium ions, which is necessary for the propagation of action potentials along myelinated axons.
5. Conclude that the high concentration of voltage-gated sodium channels at the nodes of Ranvier is critical for the saltatory conduction of nerve impulses, allowing for efficient and rapid signal transmission along the axon.