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Question #45714
The Question
A desert mammal is subjected to extreme environmental heat stress, causing a critical drop in cellular ATP production due to the impairment of mitochondrial enzymes in its renal tissue. Based on the principles of the counter-current mechanism, which of the following will be the primary physiological consequence?
Options
- A.
Failure of active NaCl transport in the thick ascending limb, resulting in the production of dilute urine even if ADH is secreted.
- B.
Impairment of passive NaCl efflux from the thin ascending limb, causing a collapse of the medullary gradient and severe diuresis.
- C.
Inability of the vasa recta to actively pump NaCl into the medullary interstitium, resulting in urine that is isosmotic to the cortex.
- D.
Failure of active water reabsorption in the descending limb of the Loop of Henle, leading to immediate dehydration.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Counter-Current Mechanism Multiplier|Thermal Tolerance Ranges|Active Solute Transport
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that ADH is the sole factor for concentrating urine, forgetting that ADH only provides the 'permeability' (aquaporins).
The actual 'driving force' for water reabsorption is the medullary osmotic gradient, which is strictly dependent on the ATP-driven active transport of NaCl in the thick ascending limb.
The trap also tests the exact locations of active vs. passive transport in the Loop of Henle.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Counter-Current Mechanism Multiplier |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |