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All of the following statements about a nerve impulse are true, except
which one?
A. The magnitude of an impulse is always the same
B. After one impulse there is a refractory period when the axon cannot
be restimulated
C. A nerve impulse can pass along an axon in one direction only
D. It has a threshold below which it cannot be stimulated
E. The resting potential of an axon is - 70mV
The answer is B but i am confused why. I thought that the whole point of the refractory period was to make it impossible for further action potentials to be generate (as the sodium voltage gated channels are closed)?
which one?
A. The magnitude of an impulse is always the same
B. After one impulse there is a refractory period when the axon cannot
be restimulated
C. A nerve impulse can pass along an axon in one direction only
D. It has a threshold below which it cannot be stimulated
E. The resting potential of an axon is - 70mV
The answer is B but i am confused why. I thought that the whole point of the refractory period was to make it impossible for further action potentials to be generate (as the sodium voltage gated channels are closed)?
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i think maybe its because it says “impulse” rather than “action potential”? because there’s always a refractory period after an action potential but maybe it’s because they aren’t the same thing. they’re similar but not the same. nerve impulse=the “message” carried by the neurones and action potential=the change in voltage AFTER the impulse is received. I was confused as well (i think this question is a BBO sample paper one, right?) but i guess the whole point is to make it difficult!
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