The following four steps describe the initiation of an impulse to the

The following four steps describe the initiation of an impulse to the

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The following four steps describe the initiation of an impulse to the “resetting” of a neuron to prepare  for a second stimulation:  1. Action potential.  Unlike a graded potential, an action potential is capable of traveling  long distances. If a depolarizing graded potential is sufficiently large, Na +  channels in the  trigger zone open. In response, Na +  on the outside of the membrane becomes depolarized  (as in a graded potential). If the stimulus is strong enough—that is, if it is above a certain  threshold level—additional Na +  gates open, increasing the flow of Na +  even more, causing  an action potential, or complete depolarization (from –70 to about +30 millivolts). This in  turn stimulates neighboring Na +  gates, farther down the axon, to open. In this manner, the  action potential travels down the length of the axon as opened Na
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This note was uploaded on 11/10/2011 for the course PT 101 taught by Professor Staff during the Spring '10 term at Texas State.

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