A slight rise in arterial PCO₂ from normal resting values at sea level is a much stronger stimulus for increasing ventilation than a comparable fall in arterial PO₂ under the same conditions.

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Quizplus · Accepted Answer

This is because the respiratory system is primarily regulated by the need to maintain proper acid-base balance in the body, which is controlled by arterial PCO₂ levels. A rise in arterial PCO₂ signals the need to increase ventilation in order to eliminate excess CO₂ and restore acid-base balance, while a fall in arterial PO₂ is more of a signal to increase perfusion to tissues in need of oxygen. Therefore, a slight rise in arterial PCO₂ is a stronger stimulus for increased ventilation.

A Slight Rise in Arterial PCO₂ from Normal Resting Values