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Question #45740
The Question
The Proximal Convoluted Tubule (PCT) is lined by simple cuboidal brush border epithelium that facilitates the bulk reabsorption of filtrate. If a pharmacological agent selectively and completely inhibits the Na⁺/K⁺-ATPase pumps on the basolateral membrane of the PCT, which of the following physiological consequences will NOT occur?
Options
- A.
Appearance of glucose and amino acids in the urine despite normal blood plasma concentrations.
- B.
Decreased secretion of H⁺ ions into the tubular lumen, potentially contributing to metabolic acidosis.
- C.
The filtrate leaving the PCT and entering the descending limb of Henle becomes highly hypotonic.
- D.
A drastic reduction in the obligatory reabsorption of water, leading to profound volume depletion.
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
Proximal Convoluted Tubule Selectivity|Diuretic Dynamics|Sodium-Potassium Pump
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Location-Specific Osmolarity.
Students often mistakenly equate 'massive water loss/diuresis' with 'hypotonic filtrate' at the site of inhibition.
They fail to realize that because the PCT epithelium is highly aquaporin-rich and freely permeable, any unabsorbed solutes will hold water osmotically, keeping the luminal fluid strictly isotonic to plasma.
The trap tests the distinction between volume reduction and osmolarity changes in specific nephron segments.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Proximal Convoluted Tubule Selectivity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |