Question

When $C{O}_2$ concentration in blood increases, breathing becomes

• A. Slow and deep
• B. Faster and deeper
• C. Shallower and slow
• D. There is no effect on breathing

Answer 1

The correct option is B Faster and deeper

During breathing process, the level of CO${}_2$ in blood acts directly on the brain as the respiratory mechanism is controlled by the medulla oblongata, part of the hind brain. High levels of carbon dioxide correspond with high levels of acid (low pH) and signal the need for more oxygen. A rise in PCO${}_2$ (a condition called as hypercapnia) decreases the pH level of cerebrospinal fluid. This excites the central chemoreceptors resulting in an increase in the depth and rate of respiration, a condition called hyperventilation. The resulting increase in alveolar ventilation flushes carbon dioxide out of the blood which increases the blood pH

So, the correct answer is 'Faster and deeper'