Question

The respiratory centre in the brain is stimulated by $C{O}_2$

• A. $C{O}_2$ concentration in venous blood
• B. $O_2$ concentration in arterial blood
• C. $C{O}_2$ concentration in arterial blood
• D. $O_2$ concentration in venous blood

Answer 1

The correct option is A

$C{O}_2$ concentration in venous blood

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.