Question

what is the term used for the opening of the voltage - gated sodium channel at the nodes of ranvier due to the presence of sodium ions?
hyperpolarization
action potential
resting potential
saltatory conduction

Explanation:

• Hyperpolarization: Refers to a change in a cell's membrane potential that makes it more negative than the resting potential. It is not related to the opening of voltage - gated sodium channels at the nodes of Ranvier.
• Action potential: A rapid rise and fall in membrane potential. While action potentials involve sodium channels, the specific term for the opening of voltage - gated sodium channels at the nodes of Ranvier (which are spaced along myelinated axons) is not simply "action potential" in this context.
• Resting potential: The baseline membrane potential of a cell when it is not actively transmitting an impulse. It has no direct relation to the opening of voltage - gated sodium channels.
• Saltatory conduction: In myelinated neurons, the action potential "jumps" from one node of Ranvier to the next. At each node, voltage - gated sodium channels open due to the presence of sodium ions (as the depolarization from the previous node spreads electrotonically to the next node), which is characteristic of saltatory conduction.

Answer:

Saltatory conduction