An epithelial cell layer bathed in physiological saline solution on both apical and basolateral surfaces starts out in a steady state in which there is constant absorption of Na⁺, Cl^-, and H₂O. The addition of ouabain to the basolateral side will cause: A) Intracellular Na⁺ to rise and intracellular K⁺ to remain constant B) Intracellular Na⁺ to fall and intracellular K⁺ to rise C) Intracellular Na⁺ to rise and intracellular K⁺ to fall D) Intracellular Na⁺ to remain constant and intracellular K⁺ to fall E) Intracellular Na⁺ to remain constant and intracellular K⁺ to remain constant

Question

Quizplus · Accepted Answer

Ouabain inhibits the Na+/K+ ATPase pump, leading to an accumulation of Na+ inside the cell and a decrease in K+ inside the cell as the pump can no longer exchange intracellular Na+ for extracellular K+.

An Epithelial Cell Layer Bathed in Physiological Saline Solution on Both