PATHOLOGY MCQ
IMMUNE RESPONSE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Once the threshold potential is reached in a neuron, which of the following occurs?
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the interior of the cell becomes negative
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K+ channels open
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Na+ channels close
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an action potential is generated
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Explanation:
Detailed explanation-1: -The threshold potential opens voltage-gated sodium channels and causes a large influx of sodium ions. This phase is called the depolarization.
Detailed explanation-2: -At each node, the membrane depolarizes above the threshold voltage, and the influx of sodium ions again initiates the action potential through Nav. This pattern of node-to-node propagation, saltatory conduction, can increase the conduction velocity by more than an order of magnitude over unmyelinated axons.
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