In the presence of an antagonist that specifically targets the voltage-gated Na+ channels in muscle, an action potential in an alpha motor nerve would result in:
Question
In the presence of an antagonist that specifically targets the voltage-gated Na+ channels in muscle, an action potential in an alpha motor nerve would result in:
Solution
An antagonist that specifically targets the voltage-gated Na+ channels in muscle would prevent the influx of Na+ ions into the muscle cells. This would inhibit the depolarization phase of the action potential in the muscle, preventing it from reaching the threshold potential necessary to trigger muscle contraction.
Here are the steps:
- The antagonist binds to the voltage-gated Na+ channels in the muscle cells, blocking them.
- This prevents Na+ ions from entering the muscle cells when an action potential arrives from the alpha motor nerve.
- Without the influx of Na+ ions, the muscle cells cannot depolarize, or change their membrane potential from negative to positive.
- This means the muscle cells cannot reach the threshold potential necessary to trigger an action potential of their own.
- Without an action potential in the muscle cells, they cannot contract.
So, in the presence of such an antagonist, an action potential in an alpha motor nerve would not result in muscle contraction.
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