Once the threshold potential is reached,
A)K⁺ channels open.
B)Na⁺ channels close.
C)an action potential is inevitable.
D)the interior of the cell becomes negative with respect to the outside.

Question

Quizplus · Accepted Answer

The threshold potential is the critical voltage level that a neuron must reach to generate an action potential. Upon reaching the threshold, voltage-gated sodium channels open, allowing sodium ions to rush into the cell, causing depolarization and triggering an action potential. Therefore, choice C is the best answer as it accurately describes what happens when the threshold potential is reached. Choices A and D are incorrect as they do not capture the entire process, and choice B is incorrect as sodium channels are actually opening at this stage, not closing.

Once the Threshold Potential Is Reached