Question

How would the absolute refractory period be affected if voltage-gated sodium channels remained inactivated?

A) It would be longer than normal.
B) It would be shorter than normal.
C) It would be the same whether the channels remained inactivated or not.
D) None of the answers are correct.

Answer 1

The absolute refractory period would be longer than normal (option A) if voltage-gated sodium channels remained inactivated, as a new action potential cannot be initiated until these channels recover from inactivation.

Step-by-step explanation:

If voltage-gated sodium channels remained inactivated, the absolute refractory period would be affected by becoming longer than normal (option A). During the absolute refractory period, another action potential cannot be initiated because the voltage-gated Na+ channels are inactivated and unable to open.

If these channels remain in this state, they cannot transition back to the resting state, and hence, no new action potential can be generated until they recover from inactivation. The flow of K+ out of the cell during the refractory period further prevents depolarization, requiring an even stronger stimulus should the channels return to the resting state.