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Question #45724
The Question
A patient suffers a localized ischemic injury that selectively destroys the hypothalamic osmoreceptors, while the Juxtaglomerular Apparatus (JGA) remains fully functional. If this patient experiences a significant drop in glomerular blood flow, which of the following physiological consequences will most likely occur?
Options
- A.
Severe hypernatremia, because Aldosterone-driven sodium retention proceeds without the osmoreceptor-mediated behavioral thirst response.
- B.
Severe hyponatremia, because the lack of ADH prevents water reabsorption, leading to excessive dilution of the blood plasma.
- C.
Complete suppression of the RAAS cascade, as Renin secretion by JG cells strictly requires synergistic signaling from the neurohypophysis.
- D.
Compensatory hypersecretion of Atrial Natriuretic Factor (ANF) to directly stimulate the thirst center and restore blood volume.
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
ADH|Angiotensin II|Hypothalamus|Posterior_Pituitary
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often conflate the triggers for RAAS and ADH, assuming they are a single inseparable pathway.
While they work synergistically to restore blood volume, their primary sensors are distinct.
The trap lies in understanding that uncoupling these systems (active RAAS + inactive osmoreceptors) leads to unchecked physiological sodium retention without the compensatory behavioral water intake, causing hypernatremia.
Option B serves as a 'Common Half-Truth' trap by correctly stating ADH prevents water reabsorption, but incorrectly concluding it leads to plasma dilution.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | RAAS Pathway Feedback Loop |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |