Which set of ions is necessary for the nerve impulse conduction?

Options

A. `Na^(+) and K^(+)`
B. `Na^(+) and Ca^(++)`
C. `Ca^(++) and K^(+)`
D. `Na^(+) and Mg^(++)`

Answer

### Step-by-Step Solution:

1. **Understanding Nerve Impulse Conduction**:
- Nerve impulse conduction refers to the process by which electrical signals are transmitted along the nerve cells (neurons). This process involves changes in the electrical charge across the neuron's membrane.

2. **Role of Ions in Nerve Impulse**:
- The conduction of nerve impulses primarily involves the movement of specific ions across the neuron's membrane. The key ions involved are sodium (Na⁺) and potassium (K⁺).

3. **Depolarization Phase**:
- When a nerve impulse is initiated, sodium channels open, allowing sodium ions to flow into the neuron. This influx of sodium ions causes depolarization, which is a change in the electrical charge inside the neuron, making it more positive.

4. **Repolarization Phase**:
- After depolarization, potassium channels open, allowing potassium ions to flow out of the neuron. This efflux of potassium ions helps to restore the original negative charge inside the neuron, a process known as repolarization.

5. **Conclusion**:
- The primary ions necessary for nerve impulse conduction are sodium (Na⁺) and potassium (K⁺). Other ions like calcium (Ca²⁺) play roles in neurotransmitter release but are not directly involved in the conduction of the nerve impulse itself.

### Final Answer:
The set of ions necessary for nerve impulse conduction is **Sodium (Na⁺) and Potassium (K⁺)**.

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