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Question #45758
The Question
A patient suffers from massive hypotonic fluid loss (polyuria) and intense thirst despite having elevated serum levels of Antidiuretic Hormone (ADH) with a normal biological half-life. Based on the principles of chemical coordination and renal physiology, which of the following correctly identifies the underlying molecular defect?
Options
- A.
ADH fails to cross the phospholipid bilayer of the collecting duct cells to interact with its intracellular receptors.
- B.
Defective osmoreceptors in the hypothalamus fail to stimulate the neurohypophysis, disrupting the feedback loop.
- C.
A failure in the membrane-bound receptor's secondary messenger cascade (cAMP) prevents the insertion of Aquaporin channels.
- D.
Hyperactivity of the counter-current mechanism in the vasa recta washes out the medullary interstitial osmolarity gradient.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Diuretic Dynamics|Hormone Half-life Logic|Secondary Messenger Cascade
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating 'Excretory Products' with 'Mechanism of Hormone Action'.
Students often reflexively link Diabetes Insipidus only to a deficiency of ADH (Central DI).
This question forces them to apply the concept of peptide hormone signaling (membrane receptors -> secondary messengers -> cellular response) to deduce that a receptor/cAMP failure produces the same physiological outcome (hypotonic polyuria) even when the hormone is abundant.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Diuretic Dynamics |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |