STANDARDZoology-Neural Control and Coordination
STANDARD Zoology Nerve Impulse MCQ Question
Type: MCQ-conceptual-Medium-Class 11
During the propagation of a nerve impulse, the action potential results from the movement of
A
K⁺ ions from intracellular fluid to extracellular fluid
B
Na⁺ ions from extracellular fluid to intracellular fluid
C
K⁺ ions from extracellular fluid to intracellular fluid
D
Na⁺ ions from intracellular fluid to extracellular fluid
Correct Answer
Option B
Detailed Explanation
When a depolarizing graded potential or some other stimulus causes the membrane of the axon to depolarize to threshold, voltage gated Na⁺ channels open rapidly. Both the electrical and chemical gradients favor inward movement of Na⁺, causing the depolarizing phase of the action potential, changing the membrane potential from –55 mV to +30 mV.
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