Absolute refractory period during nerve impulse conduction is the period of

Options

A. Repolarization
B. Depolarization
C. Both repolarization and depolarization
D. Neither repolarization and depolarization

Answer

**Step-by-Step Solution:**

1. **Understanding Refractory Periods**: The refractory period is the time during which a neuron is unable to fire another action potential. It is divided into two types: absolute refractory period and relative refractory period.

2. **Defining Absolute Refractory Period**: The absolute refractory period is the phase during which no new action potential can be initiated, regardless of the strength of the stimulus. This occurs immediately after an action potential.

3. **Phases of Action Potential**:
- **Depolarization**: This is the initial phase where sodium channels open, allowing sodium ions to flow into the neuron, causing the inside of the neuron to become more positive.
- **Repolarization**: Following depolarization, potassium channels open, allowing potassium ions to flow out of the neuron, which helps to restore the negative internal environment of the neuron.

4. **Role of Ion Channels**: During the absolute refractory period, the sodium channels are inactivated (closed) and cannot reopen until the membrane potential returns to a resting state. This is crucial because it ensures that action potentials only travel in one direction along the neuron.

5. **Conclusion**: The absolute refractory period is primarily associated with the repolarization phase of the action potential. It is during this time that the neuron cannot respond to any new stimulus.

**Final Answer**: The absolute refractory period during nerve impulse conduction is the period of repolarization.

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