GCEBiologyExcretion2023

Antidiuretic hormone (ADH) promotes water conservation in the body by

Aincreasing the rate of glomerular filtration in the Bowman's capsule
Bstimulating the proximal convoluted tubule to secrete more urea
Cincreasing the permeability of the collecting duct to waterCORRECT
Ddecreasing the reabsorption of sodium ions in the loop of Henle
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Why the answer is C, and why the others tempt you.
ADH, secreted by the posterior pituitary gland, acts on the cells of the collecting duct and distal convoluted tubule, increasing their permeability to water by inserting aquaporin channels into the cell membranes. This allows more water to be reabsorbed by osmosis into the surrounding hypertonic medullary tissue, producing concentrated urine. ADH does not directly affect glomerular filtration rate or urea secretion.
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