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An action potential is ultimately caused by:

a. changes in membrane permeability.
b. changes in membrane potential.
c. influx of potassium ions.
d. efflux of sodium ions.
e. Na+/K+ ATPase.

1 Answer

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Final answer:

An action potential is caused by changes in membrane permeability, specifically when a stimulus makes the cell membrane permeable to Na+ ions. This leads to depolarization and the influx of Na+ ions, resulting in a change in membrane potential. Repolarization occurs as the membrane becomes impermeable to Na+ ions and K+ ions move from high to low concentration.

Step-by-step explanation:

An action potential is ultimately caused by changes in membrane permeability. When a stimulus makes the cell membrane permeable to Na+ ions, depolarization occurs. This allows Na+ ions to enter the cell, resulting in a change in membrane potential. Repolarization follows as the membrane becomes impermeable to Na+ and K+ ions move from high to low concentration. In the long term, active transport through the Na+/K+ ATPase pump maintains the concentration differences necessary for the generation of action potentials.

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