Control of respiration · Physiology

The 'breaking point' of breath-holding is primarily determined by the buildup of which substance?

  1. Arterial PO2
  2. Arterial PCO2
  3. Blood nitrogen levels
  4. Lactic acid in the muscles
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Correct answer: Arterial PCO2

While low oxygen eventually contributes, the irresistible urge to breathe during a breath-hold is primarily driven by the accumulation of arterial CO2, which stimulates both central and peripheral chemoreceptors.

Difficulty: Medium Question 37 of 40

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