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Question #45717
The Question
A pharmacological agent specifically inhibits the active transport of Na+, K+, and Cl- in the thick ascending limb of Henle's loop. Which of the following will be the primary physiological consequence of this inhibition?
Options
- A.
The vasa recta will actively secrete NaCl into the medullary interstitium to maintain the 1200 mOsmL-1 gradient.
- B.
The medullary interstitial osmotic gradient will diminish, preventing water reabsorption from the collecting duct even in the presence of ADH.
- C.
The descending limb of Henle's loop will become actively permeable to electrolytes to compensate for the disrupted multiplier.
- D.
Obligatory water reabsorption in the Proximal Convoluted Tubule (PCT) will drastically decrease due to the loss of the medullary gradient.
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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
Vasa_recta|Henle’s_Loop|Furosemide
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the 'permeability factor' and the 'driving force' for water reabsorption.
Students often assume ADH alone concentrates urine, forgetting that ADH merely inserts aquaporins (permeability).
The actual osmotic driving force pulling water out of the collecting duct is the medullary gradient generated by the thick ascending limb (the multiplier).
If the multiplier fails, ADH is rendered functionally ineffective.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Counter-Current Exchanger |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |