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Question #46322
The Question
A mountaineer rapidly ascends to an altitude of 5,000 meters, experiencing acute hypoxia. Which of the following best describes the immediate neural feedback mechanism and its subsequent physiological conflict regarding oxygen transport?
Options
- A.
Hypoxia stimulates central chemoreceptors in the medulla to increase ventilation, causing CO2 washout, respiratory alkalosis, and a rightward shift of the O2-Hb dissociation curve.
- B.
Hypoxia stimulates peripheral chemoreceptors in the aortic and carotid bodies to increase ventilation, causing CO2 washout, respiratory alkalosis, and a leftward shift of the O2-Hb dissociation curve.
- C.
Hypoxia directly stimulates the pneumotaxic center to decrease inspiratory duration, leading to CO2 retention, respiratory acidosis, and a leftward shift of the O2-Hb dissociation curve.
- D.
Hypoxia inhibits the chemosensitive area adjacent to the rhythm center, causing hypoventilation, CO2 accumulation, and a rightward shift of the O2-Hb dissociation curve.
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
Carotid_Body|Medulla_Oblongata|Partial_Pressure_Gradient_Logic
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT line that high altitude acclimatization 'decreases Hb affinity for O2' (a long-term adaptation via 2,3-BPG shifting the curve right).
However, they fail to synthesize the immediate acute effect: hyperventilation causes CO2 washout (alkalosis), which shifts the curve to the left.
Additionally, it tests a critical Location Trap: central chemoreceptors (medulla) respond to CO2/H+, whereas only peripheral chemoreceptors respond to significant drops in pO2.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Breathing and Exchange of Gases - Class 11 |
| Concept | Neural Regulation Feedback |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |