Biology Homeostasis PMDC Conceptual Practice
PMDC Verified Question 42 of 99
The reabsorption of water from renal collecting ducts into the hypertonic medullary interstitium is directly increased by:
A
Magnesium ions
B
High urine pH
C
Aldosterone
D
Antidiuretic hormone (ADH)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Antidiuretic hormone (ADH)
Concept: Endocrine regulation of collecting duct permeability.

Solution: ADH (vasopressin) triggers the insertion of aquaporin-2 water channels into the luminal membranes of collecting duct principal cells, promoting water reabsorption.

Why other options are incorrect:
  • Option A & Option B: Magnesium concentration and pH do not act as primary hormonal signals for aquaporin insertion.

  • Option C (Aldosterone): Primarily stimulates active sodium reabsorption and potassium secretion.

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