Q. During the propagation of a nerve impulse, the action potential results from the movement of
A) Na⁺ ions from extracellular fluid to intracellular fluid
B) K⁺ ions from extracellular fluid to intracellular fluid
C) Na⁺ ions from intracellular fluid to extracellular fluid
D) K⁺ ions from intracellular fluid to extracellular fluid
Explanation
[Solution from source] At the stimulated site voltage-gated Na⁺ channels open and Na⁺ rushes in from the extracellular fluid, reversing the polarity and producing the action potential. K⁺ moving outward causes repolarisation afterwards, not the action potential itself. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.