Question:
Action potential in nerve fibers is unidirectional primarily due to which of the following mechanisms
Action potential in nerve fibers is unidirectional primarily due to which of the following mechanisms
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Refractory period = One-way street for the nerve impulse.
Updated On: May 15, 2026
- Immediate decrease in extracellular potassium after repolarization
- Activation of sodium channels during depolarization
- Inactivation of voltage-gated sodium channels during the refractory period
- Increased membrane permeability to ions
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The Correct Option is C
Solution and Explanation
Step 1: Concept
Action potentials travel along an axon in one direction, from the cell body to the axon terminals.
Step 2: Meaning
Refractory period is the time during which a cell cannot be re-excited.
Step 3: Analysis
After sodium channels open during depolarization, they enter an inactivated state. They cannot reopen until the membrane has repolarized and returned to the resting state.
Step 4: Conclusion
This "inactivated" zone behind the moving impulse prevents the signal from traveling backward. Final Answer: (C)
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