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Question #45715
The Question
A patient with severe hyperkalemia (elevated extracellular K+ levels) is observed to produce highly concentrated urine despite having abnormally low plasma osmolarity. Assuming the counter-current multiplier system in the Loop of Henle is structurally intact, which of the following best explains this physiological anomaly?
Options
- A.
Hyperkalemia directly accelerates the active transport of NaCl in the thick ascending limb, hyperactivating the medullary concentration gradient.
- B.
Elevated extracellular K+ depolarizes the resting membrane potential of hypothalamic osmoreceptors, triggering non-homeostatic ADH release.
- C.
High K+ levels hyperpolarize the osmoreceptor membranes, increasing their sensitivity to minor changes in blood volume.
- D.
Hyperkalemia inhibits the Na+/K+ ATPase in the collecting duct, forcing obligatory water reabsorption independent of ADH.
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
Loop of Henle|Resting Membrane Potential Ionic Flux|ADH (Vasopressin) Logic
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often isolate human physiology chapters.
They understand the Counter-Current Mechanism and RMP separately but fail to integrate them.
The trap relies on the misconception that abnormal urine concentration must always stem from a direct defect in the Loop of Henle (the multiplier), ignoring the upstream neuro-endocrine feedback loop where ionic imbalances (like K+) disrupt the synaptic signaling of osmoreceptors.
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 |