Answer: About 180 litres.
- A About 1.5 litres
- B About 180 litres
- C About 10 litres
- D About 500 litres
Correct answer: B. About 180 litres
Explanation: The kidneys filter about 180 litres of fluid a day, though most of it is reabsorbed.
Filtrate flows through four functionally distinct stages of the nephron: Bowman's capsule filters blood, the PCT reabsorbs most useful substances unconditionally, the Loop of Henle builds a concentration gradient via counter-current exchange, the DCT secretes selected substances, and the collecting duct performs the final ADH-controlled water reabsorption.
Concept context
Nitrogenous waste, kidney structure, urine formation in the nephron, and hormonal regulation of excretion.
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