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Question #45708
The Question
A specific nephrotoxin completely inhibits the basolateral Na+/K+ ATPase pumps in the simple cuboidal brush-border epithelium of a mammalian nephron. Which of the following statements regarding the immediate physiological fallout is INCORRECT?
Options
- A.
Secondary active transport of high-threshold substances like glucose and amino acids is halted, leading to their appearance in urine.
- B.
Obligatory water reabsorption fails, causing a massive increase in the volume of filtrate entering the descending limb of the Loop of Henle.
- C.
Facultative reabsorption in the distal convoluted tubule (DCT) and collecting duct will fully compensate for the massive filtrate overflow under maximal ADH and Aldosterone stimulation.
- D.
The osmolarity of the tubular fluid leaving the PCT will remain approximately isotonic to the cortical interstitium, but its total volume will be abnormally high.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Glomerular Filtration Fraction|Proximal Convoluted Tubule Selectivity|Resting Membrane Potential Ionic Flux
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Quantitative Nuance and Functional Overlap.
Students often overestimate the compensatory power of the endocrine system (ADH/Aldosterone) on the distal nephron.
The trap relies on failing to quantitatively distinguish between the massive 'obligatory' bulk reabsorption in the PCT (which handles the vast majority of the 180L/day filtrate) and the limited, fine-tuning 'facultative' reabsorption in the DCT/CD.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Glomerular Filtration Fraction |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |