The generation and propagation of an action potential involves several key steps:

1. **Resting Potential**: In a resting neuron, the inside of the neuron is negatively charged relative to the outside. This is due to the distribution of ions across the neuron's membrane, including sodium (Na+) and potassium (K+) ions. The resting membrane potential is typically -70 mV.

2. **Stimulus**: A stimulus causes the cell membrane at that point to depolarize (become less negative). If the stimulus is strong enough and reaches the threshold potential (usually -55 mV), it triggers an action potential.

3. **Depolarization**: Once the threshold potential is reached, voltage-gated Na+ channels open. Na+ ions rush into the neuron due to the concentration gradient, making the inside of the neuron positively charged relative to the outside. This rapid change in charge is the depolarization phase of the action potential.

4. **Repolarization**: At the peak of the action potential (+40 mV), the Na+ channels close and voltage-gated K+ channels open. K+ ions rush out of the neuron, returning the charge inside the neuron to a negative value. This is the repolarization phase.

5. **Hyperpolarization**: Sometimes, the K+ channels stay open a bit too long, causing more K+ to leave the neuron than is necessary. This results in the neuron becoming more negative than the resting potential, a state known as hyperpolarization.

6. **Return to Resting Potential**: The neuron's sodium-potassium pump restores the original distribution of Na+ and K+ ions, returning the neuron to its resting potential and readying it for the next action potential.

7. **Propagation of the Action Potential**: The action potential propagates down the neuron's axon like a wave. The influx of Na+ ions during depolarization causes the next section of the neuron to reach threshold and depolarize. This continues all the way down the axon to the synaptic terminals, where it triggers the release of neurotransmitters into the synapse.

This entire process happens very quickly, in just a few milliseconds, and allows neurons to transmit information over long distances.

Question

The generation and propagation of an action potential involves several key steps:

1. **Resting Potential**: In a resting neuron, the inside of the neuron is negatively charged relative to the outside. This is due to the distribution of ions across the neuron's membrane, including sodium (Na+) and potassium (K+) ions. The resting membrane potential is typically -70 mV.

2. **Stimulus**: A stimulus causes the cell membrane at that point to depolarize (become less negative). If the stimulus is strong enough and reaches the threshold potential (usually -55 mV), it triggers an action potential.

3. **Depolarization**: Once the threshold potential is reached, voltage-gated Na+ channels open. Na+ ions rush into the neuron due to the concentration gradient, making the inside of the neuron positively charged relative to the outside. This rapid change in charge is the depolarization phase of the action potential.

4. **Repolarization**: At the peak of the action potential (+40 mV), the Na+ channels close and voltage-gated K+ channels open. K+ ions rush out of the neuron, returning the charge inside the neuron to a negative value. This is the repolarization phase.

5. **Hyperpolarization**: Sometimes, the K+ channels stay open a bit too long, causing more K+ to leave the neuron than is necessary. This results in the neuron becoming more negative than the resting potential, a state known as hyperpolarization.

6. **Return to Resting Potential**: The neuron's sodium-potassium pump restores the original distribution of Na+ and K+ ions, returning the neuron to its resting potential and readying it for the next action potential.

7. **Propagation of the Action Potential**: The action potential propagates down the neuron's axon like a wave. The influx of Na+ ions during depolarization causes the next section of the neuron to reach threshold and depolarize. This continues all the way down the axon to the synaptic terminals, where it triggers the release of neurotransmitters into the synapse.

This entire process happens very quickly, in just a few milliseconds, and allows neurons to transmit information over long distances.

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