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Question #46367
The Question
During extreme, high-intensity exercise, skeletal muscles undergo rapid anaerobic glycolysis, leading to severe localized lactic acidosis and elevated pCO2. Which of the following statements regarding the physiological consequences of this metabolic stress is INCORRECT?
Options
- A.
The localized increase in H+ concentration and pCO2 shifts the oxygen-haemoglobin dissociation curve to the right, facilitating O2 unloading.
- B.
The extreme systemic drop in pH continuously accelerates the ion channel kinetics in the SA and AV nodes, ensuring cardiac output rises linearly with metabolic demand.
- C.
Chemoreceptors in the aortic arch and carotid artery are strongly stimulated by the elevated pCO2 and H+ concentration, signaling the respiratory rhythm centre.
- D.
Skeletal muscle cells regenerate NAD+ from NADH during the reduction of pyruvic acid to lactic acid, a process catalyzed by lactate dehydrogenase.
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
Conducting System Sequence|Haldane Effect vs. Bohr Effect|Fermentation Limitations
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume physiological compensatory mechanisms (like heart rate increasing during exercise) scale infinitely.
The trap relies on confusing the sympathetic nervous system's initial stimulatory effect with the direct, depressive biochemical effect of extreme acidosis (low pH) on cardiac electrophysiology and conduction velocity.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Body Fluids and Circulation - Class 11 |
| Concept | Conducting System Sequence |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |