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Multiple Choice
During the relative refractory period, a larger-than-normal depolarizing stimulus can:
A
close all voltage-gated sodium channels
B
initiate a second action potential
C
prevent any action potential from occurring
D
cause the neuron to become hyperpolarized
Verified step by step guidance
1
Understand the concept of the relative refractory period: During this phase, some voltage-gated sodium channels have returned to their resting state and are capable of opening again, but the neuron is still recovering from the previous action potential. The membrane potential is closer to the threshold but not fully reset.
Recall the role of voltage-gated sodium channels in action potential initiation: These channels open in response to a depolarizing stimulus, allowing sodium ions to flow into the cell, which drives the membrane potential toward the threshold for an action potential.
Consider the conditions during the relative refractory period: While some sodium channels are ready to open, the neuron requires a larger-than-normal depolarizing stimulus to reach the threshold because the membrane potential is still partially hyperpolarized or recovering.
Evaluate the options provided: Closing all voltage-gated sodium channels would prevent any action potential from occurring, which is not consistent with the relative refractory period. Hyperpolarization occurs during the absolute refractory period, not the relative refractory period. A larger-than-normal depolarizing stimulus can initiate a second action potential during the relative refractory period.
Conclude that the correct answer is: 'initiate a second action potential,' as this aligns with the physiological state of the neuron during the relative refractory period and the requirement for a stronger stimulus to overcome the partially reset membrane potential.