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When the action potential begins, sodium...

When the action potential begins, sodium gates open, allowing to cross the membrane. Now the polarity changes to:

A

negative outside and positive inside

B

positive outside and negative inside

C

there is no difference in charge between outside and inside

D

any one of the above could be correct

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The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding Resting Potential:** - At rest, a neuron has a resting potential where the inside of the membrane is negatively charged compared to the outside. This is primarily due to a higher concentration of potassium ions (K+) inside the cell and a higher concentration of sodium ions (Na+) outside the cell. 2. **Initiation of Action Potential:** - When a neuron is stimulated, voltage-gated sodium channels open. This allows sodium ions (Na+) to flow into the neuron. 3. **Change in Membrane Polarity:** - As sodium ions enter the neuron, the inside of the membrane becomes positively charged relative to the outside. This change in charge is referred to as depolarization. 4. **Polarity During Action Potential:** - At the peak of the action potential, the inside of the neuron is now positively charged, while the outside is negatively charged. Therefore, the polarity changes to negative outside and positive inside. 5. **Conclusion:** - The correct answer to the question is that when the action potential begins, the polarity changes to negative outside and positive inside.
**Step-by-Step Solution:** 1. **Understanding Resting Potential:** - At rest, a neuron has a resting potential where the inside of the membrane is negatively charged compared to the outside. This is primarily due to a higher concentration of potassium ions (K+) inside the cell and a higher concentration of sodium ions (Na+) outside the cell. 2. **Initiation of Action Potential:** - When a neuron is stimulated, voltage-gated sodium channels open. This allows sodium ions (Na+) to flow into the neuron. ...
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