EMBRYOLOGY
NERVOUS SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The sodium-potassium pump shuttles ions across the membrane.
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The membrane depolarizes above a certain threshold potential.
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Voltage-gated potassium channels open, and K+ ions diffuse out of the neuron.
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There is an undershoot of the resting potential.
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Detailed explanation-1: -[5] Depolarizing current from an action potential travels very rapidly through the cytoplasm of axons, insulated by myelin until reaching the next node of Ranvier. At each node, the membrane depolarizes above the threshold voltage, and the influx of sodium ions again initiates the action potential through Nav.
Detailed explanation-2: -Synaptic inputs to a neuron cause the membrane to depolarize or hyperpolarize; that is, they cause the membrane potential to rise or fall. Action potentials are triggered when enough depolarization accumulates to bring the membrane potential up to threshold.
Detailed explanation-3: -On depolarization of the membrane to the less negative threshold voltage, the Na+ channels open, resulting in an influx of positively charged ions (the inward Na+ current) and rapid reversal of membrane polarity.