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Question #46206
The Question
During vertebrate embryogenesis, the mesodermally-derived notochord induces the formation of the renal architecture. Suppose a teratogenic mutation specifically prevents the elongation of the nephric tubular segment that dips deep into the renal medulla, while cortical structures remain relatively intact. Which of the following physiological homeostatic imbalances would be the primary and most direct consequence of this developmental failure?
Options
- A.
The counter-current multiplier system would fail, preventing the establishment of a hyperosmolar medullary interstitium of up to 1200 mOsmol/L.
- B.
The counter-current exchange mechanism would fail due to the absence of the vasa recta, leading to an obligatory loss of glucose in the urine.
- C.
Obligatory reabsorption of water and essential nutrients would cease, as the proximal convoluted tubule fails to develop a brush border.
- D.
Conditional reabsorption of Na+ and water would halt due to the inability of the macula densa to secrete aldosterone.
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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
Notochord|Glomerular_Filtration|Mesodermal_Induction
Why This Question Is Tricky
Common Mistakes
The Conceptual Pivot lies in distinguishing the anatomical location (medulla vs. cortex) and the specific physiological roles of the counter-current multiplier (Loop of Henle) versus the exchanger (Vasa recta).
The question traps students who confuse the multiplier/exchanger functions, misattribute the sites of glucose reabsorption, or fall for the functional confusion regarding hormone secretion sites (Macula densa vs Adrenal cortex).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Evolutionary Notochord Progression |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |