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Question #45416
The Question
A patient presents with severe polyuria and dehydration. Blood analysis reveals abnormally high levels of a nonapeptide hormone synthesized in the hypothalamus and released from the pars nervosa. Intravenous administration of a synthetic analogue of this hormone fails to reduce urine volume. Which of the following best explains this physiological state?
Options
- A.
A mutation in the membrane-bound receptors of the collecting duct, preventing secondary messenger generation and causing elevated hormone levels due to absent negative feedback.
- B.
A defect in the intracellular receptors of the renal tubules, preventing the hormone-receptor complex from interacting with the genome to express aquaporins.
- C.
Hypersecretion of the hormone from the adenohypophysis due to a loss of inhibitory factors from the hypothalamus.
- D.
Failure of the hypothalamo-hypophyseal portal system to transport the synthesized hormone from the hypothalamus to the posterior pituitary.
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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
Hormone Receptors Location|Adenohypophysis vs Neurohypophysis Origin
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Differentiating between hormone deficiency and hormone resistance (receptor mutation), while simultaneously testing the biochemical classification of hormones and their specific receptor locations (membrane-bound vs. intracellular).
Students often confuse the transport mechanisms (axonal vs. portal) and receptor types for pituitary hormones.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Chemical Coordination and Integration - Class 11 |
| Concept | Adenohypophysis vs Neurohypophysis Origin |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |