Question

If the CO${}_2$ concentration in the blood increases, the rate of breathing will

• A. Decrease.
• B. Have no effect.
• C. Increase.
• D. Depends on the individual.

Answer 1

The correct option is C Increase.

• The level of CO${}_2$ usually drives the breathing rate. If the level of CO${}_2$ in blood increases by 10%, the rate of breathing almost doubles.
• When the CO${}_2$ dissolves, it combines with the water in the blood to form carbonic acid. As this acid builds up, it decreases the pH of the blood.
• This pH change is detected by the respiratory center i.e., medulla oblongata and speeds up breathing rate in order to get rid of the extra CO${}_2$. Option C is correct.