Biology Homeostasis PMDC Conceptual Practice
PMDC Verified Question 11 of 99
Antidiuretic hormone (ADH) regulates blood water potential by directly increasing water permeability in the:
A
Collecting duct
B
Ascending limb of the Loop of Henle
C
Descending limb of the Loop of Henle
D
Proximal convoluted tubule
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Collecting duct
Concept: Target site and action of ADH.

Solution: ADH binds to V2 receptors on principal cells of the collecting duct (and late DCT), triggering insertion of aquaporin-2 channels into the luminal membrane to facilitate water reabsorption.

Why other options are incorrect:
  • Option B: The ascending limb is impermeable to water under all conditions.

  • Option C: The descending limb is passively permeable to water independent of ADH.

  • Option D: The PCT reabsorbs water obligatorily independent of ADH levels.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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