NERVOUS SYSTEM SPECIAL SENSE
PERIPHERAL NERVE
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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threshold voltage, -55mV
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resting voltage, -70mV
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threshold voltage, -70mV
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resting voltage, -55mV
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Detailed explanation-1: -Most often, the threshold potential is a membrane potential value between –50 and –55 mV, but can vary based upon several factors. A neuron’s resting membrane potential (–70 mV) can be altered to either increase or decrease likelihood of reaching threshold via sodium and potassium ions.
Detailed explanation-2: -The threshold potential is usually around-50 to-55 mV. It is important to know that the action potential behaves upon the all-or-none law. This means that any subthreshold stimulus will cause nothing, while threshold and suprathreshold stimuli produce a full response of the excitable cell.
Detailed explanation-3: -As the membrane potential reaches +30 mV, slower to open voltage-gated potassium channels are now opening in the membrane. An electrochemical gradient acts on K+, as well. As K+ starts to leave the cell, taking a positive charge with it, the membrane potential begins to move back toward its resting voltage.