Question

After an action potential, the opening of additional voltage-gated ________ channels and the inactivation of sodium channels cause the membrane to return to its resting membrane potential.

a) Sodium
b) Potassium
c) Calcium
d) Chloride

Answer 1

After an action potential, additional potassium channels open and sodium channels. The correct answer is option b).

Step-by-step explanation:

After an action potential, the opening of additional voltage-gated potassium channels and the inactivation of sodium channels cause the membrane to return to its resting membrane potential. The first channels to open are the sodium ion channels during the depolarization phase, triggering the start of the action potential.

Then, voltage-gated potassium ion channels open, allowing potassium ions to flow out of the cell, leading the membrane to repolarize, and the inside of the membrane becomes negative again. As the sodium channels inactivate, no more sodium can enter the cell.

Following this, the potassium channels eventually close, and the sodium-potassium pump restores the resting membrane potential. The action potential moves down the axon like a wave, and this cycle allows the neuron to return to a state where it can transmit another action potential if stimulated.