At normal alveolar ventilation the respiratory center is stimulated by:
Correct answer: B. CO2 concentration in venous blood
- A. O2 concentration in venous blood
- B. CO2 concentration in venous blood
- C. CO2 concentration in arterial blood
- D. O2 concentration in arterial blood
Explanation
The body's respiratory centre in the medulla is normally stimulated by an increased concentration of carbon dioxide, and to a lesser extent, by decreased levels of oxygen in arterial blood. Stimulation of the respiratory centre causes an increase in the rate and depth of breathing, thus blowing off excess carbon dioxide and reducing blood acidity.
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