A short period during whirh a nerve is unable to conduct nerve impulse is called : \

Options

A. Synaptic delay
B. Refractory period
C. Resting potential
D. Critical period

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the term that describes a short period during which a nerve is unable to conduct a nerve impulse.

2. **Identifying Key Terms**:
- Nerve impulse: The electrical signal that travels along the nerve.
- Conduct: The ability of the nerve to transmit this signal.
- Short period: Indicates a temporary state.

3. **Evaluating Options**:
- **Synaptic Delay**: This refers to the time taken for a signal to cross a synapse, not a period of inactivity in a nerve.
- **Refractory Period**: This is the period after an action potential during which a nerve cannot respond to a new stimulus.
- **Resting Potential**: This is the state of the neuron when it is not conducting an impulse, but it is not a period of inactivity.
- **Critical Period**: This term is not commonly used in the context of nerve impulse conduction.

4. **Defining Refractory Period**: The refractory period is divided into two phases:
- **Absolute Refractory Period**: The nerve cannot respond to any stimulus, no matter how strong.
- **Relative Refractory Period**: The nerve can respond, but only to a very strong stimulus.

5. **Conclusion**: Based on the definitions and the context of the question, the correct answer is **Refractory Period**.

### Final Answer:
The short period during which a nerve is unable to conduct a nerve impulse is called the **Refractory Period**.

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