PHYSIOLOGY
NEUROTRANSMISSION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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potassium gates close and sodium gates open
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the Na+/K+ pump pumps sodium out of the neuron and potassium into the neuron
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potassium gates open and sodium gates close
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another action potential can be propagated
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Detailed explanation-1: -The inactivation gates of the sodium channels close, stopping the inward rush of positive ions. At the same time, the potassium channels open. There is much more potassium inside the cell than out, so when these channels open, more potassium exits than comes in.
Detailed explanation-2: -Opening of these channels causes a rapid depolarization. When the voltage-gated Na+ channels inactivate and voltage-gated K+ channels open, the action potential peaks (between 0 and +40 mV).
Detailed explanation-3: -Depolarization also opens voltage-gated K+ channels, allowing K+ efflux, which, together with rapid Na+ channel inactivation, quickly repolarizes the membrane during the falling phase of the action potential. This enables the cell to propagate electrical signals quickly and with high efficiency.