A healthy adult has a glomerular filtration rate of 120 mL/min and a filtration fraction of 20%. A substance X is freely filtered, is not reabsorbed or secreted, and its renal arteriolar handling is being studied. What is the renal plasma flow in this individual?

• A 24 mL/min
• B 240 mL/min
• C 600 mL/min ✓
• D 1200 mL/min

Explanation

Filtration fraction = GFR / RPF, so RPF = GFR / FF = 120 / 0.20 = 600 mL/min. This is a straightforward clearance and hemodynamics calculation. The distractor 240 mL/min comes from multiplying GFR by FF (120 × 0.20 = 24, then misplaced decimal), and 1200 mL/min comes from inverting the ratio (120 / 0.10).

Reference: Ganong's Review of Medical Physiology, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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