Aldosterone acts primarily on which segment of the nephron to regulate sodium and potassium balance?
- A Proximal convoluted tubule
- B Thick ascending limb of loop of Henle
- C Late distal tubule and cortical collecting duct ✓
- D Thin descending limb of loop of Henle
Correct answer: C. Late distal tubule and cortical collecting duct
Explanation
Aldosterone acts on mineralocorticoid receptors in the principal cells of the late distal tubule and cortical collecting duct. It stimulates the synthesis of Na+/K+ ATPase and increases the number of apical Na+ channels (ENaC), promoting Na+ reabsorption and K+ secretion. The proximal tubule reabsorbs the bulk of filtered sodium but is not the primary aldosterone-sensitive segment.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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