Question

When a sodium ion is rushing into a nerve cell, the cell is unable to produce another action potential regardless of how strong a stimulus is applied. This time is called the:

a) Relative refractory period
b) Threshold stimulus period
c) Absolute refractory period
d) Action potential period

Answer 1

When a sodium ion is rushing into a nerve cell, preventing the production of another action potential, this time is called the absolute refractory period (Option C).

Step-by-step explanation:

The time when a nerve cell is unable to produce another action potential despite a stimulus, due to the influx of sodium ions, is referred to as the absolute refractory period. This period occurs because the voltage-gated Na+ channel is inactivated, and no action potential can start during this phase.

After the Na+ channels return to their resting state, a new action potential can only be initiated by a stronger stimulus than the one that caused the original action potential due to the flow of K+ out of the cell, which leads to hyperpolarization and extends the time before the membrane can be depolarized again.

Thus, the correct option is C.