In axon of a neuron, the impulse is generated by exchange of

Options

A. Sodium and potassium
B. Magnesium and chlorine
C. Calcium and potassium
D. Sodium and chlorine

Answer

To answer the question, "In the axon of a neuron, the impulse is generated by the exchange of," we can break down the process step by step:

### Step-by-Step Solution:

1. **Understanding Neurons**: Neurons are the basic structural and functional units of the nervous system. They are specialized cells that detect, receive, and transmit stimuli.

2. **Parts of a Neuron**: A typical neuron consists of three main parts: the cell body, dendrites, and axon. The axon is specifically responsible for conducting nerve impulses.

3. **Resting State of the Axon**: In the resting state of the axon, the membrane is polarized. This means that the interior of the axon is negatively charged compared to the outside. The membrane is impermeable to sodium ions (Na+) and permeable to potassium ions (K+). Additionally, negatively charged proteins are present inside the axoplasm, contributing to the negative charge.

4. **Depolarization**: When a stimulus is applied to the axon, the membrane at the site of the stimulus becomes permeable to sodium ions. This allows sodium ions to rapidly enter the axon, causing the interior to become positively charged (depolarization). This change in charge is crucial for the conduction of the nerve impulse.

5. **Restoration of Resting Potential**: After the influx of sodium ions, the membrane quickly becomes permeable to potassium ions. Potassium ions then flow out of the axon, restoring the resting potential and repolarizing the membrane.

6. **Conclusion**: The generation of the nerve impulse in the axon is primarily due to the exchange of sodium (Na+) and potassium (K+) ions.

### Final Answer:
The impulse in the axon of a neuron is generated by the exchange of **sodium and potassium ions**.

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