Why does the countercurrent multiplier system in the kidney's loop of Henle concentrate urine more effectively than a single-pass system?

💡 Explanation

The countercurrent multiplier uses active transport of solutes to create a concentration gradient in the medulla of the kidney; because of this gradient, water moves out of the collecting duct by osmosis, therefore concentrating urine, rather than a single-pass system only reabsorbing a fixed amount.

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