You take 20000 breaths a day
Respiratory System
The breathing reflex is triggered by rising CO₂ in the blood, detected as a pH drop by chemoreceptors in the medulla oblongata — not by falling O₂. Hold your breath to see this firsthand.
Lung Volume2.50 L
O₂ Saturation98.0%
Blood pCO₂40.0 mmHg
Blood pH7.40
Resp. Rate12 bpm
Diaphragm contracts, thoracic volume increases, pressure drops, air rushes in.