If a marathon runner develops severe dehydration during a race, which consequence follows regarding vasopressin's (ADH) activity on the collecting ducts?

💡 Explanation

In dehydration, plasma osmolality rises, stimulating ADH release. ADH increases aquaporin insertion into collecting duct cells, because this elevates water reabsorption from the filtrate back into the bloodstream; therefore, more water is conserved, rather than being lost as urine, and osmolality decreases.

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