mushed
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Report Thread starter 11 months ago
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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)?
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kezza123321
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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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