Solved UPSC CDS/OTA Question
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Q · Respiratory System medium · 45s
The partial pressure of oxygen in arterial blood at sea level (PaO₂) is approximately:
TopicRespiratory System
Question Typemultiple choice
Difficultymedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
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At sea level, atmospheric PO₂ is ~159 mmHg, alveolar PO₂ ~100 mmHg, and arterial PaO₂ typically ~95–100 mmHg. Maintaining this gradient ensures efficient oxygen diffusion into blood.
Final Answer: Option A - 100 mmHg