PATHOLOGY MCQ
NERVOUS SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated potassium channels farther down the axon.
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Potassium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon.
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Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon.
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Potassium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated potassium channels farther down the axon.
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Detailed explanation-1: -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.
Detailed explanation-2: -The action potential travels down the axon as voltage-gated ion channels are opened by the spreading depolarization. In unmyelinated axons, this happens in a continuous fashion because there are voltage-gated channels throughout the membrane.
Detailed explanation-3: -The action potential propagates along the axon of the cell in a rather simple manner. When the cell membrane of the axon hillock is stimulated enough, depolarization will take place. The influx of sodium ions into the cell will cause the inside of the cell to become positively charged, thereby reversing the polarity.
Detailed explanation-4: -An action potential is a transient, electrical signal, which is caused by a rapid change in resting membrane potential (-70 mV). This occurs when the threshold potential (-55 mV) is reached, this causes a rapid opening in the voltage-gated sodium channels leading to an influx of sodium ions into the cell.