Refer to the figure showing the conduction of an action potential traveling from left to right in a myelinated axon.Note the action potential at node 2. Which statement about section 2 of the axon is true? A) Depolarization is caused here by the opening of voltage-gated K⁺ channels. B) The speed of the action potential in this axon depends mostly on its diameter. C) Na⁺ channels remain open here until the action potential has reached the axon terminal. D) A loss of signal will occur as the action potential travels to each adjacent node. E) Na⁺ channels will inactivate at this node and enter a refractory state.

Question

Quizplus · Accepted Answer

At node 2, Na+ channels will inactivate and enter a refractory state, which allows for the action potential to continue propagating along the axon.  Option A is incorrect because voltage-gated K+ channels do not cause depolarization; they actually contribute to repolarization. Option B is incorrect because myelination also plays a significant role in the speed of action potential conduction. Option C is incorrect because Na+ channels will already be inactivated at this point, and option D is incorrect because there is no loss of signal as the action potential jumps from node to node.

Refer to the Figure Showing the Conduction of an Action