Question

Forced deep breathing during rest for some time is followed by temporary stoppage of breathing because of.

• A. Low $C{O}_2$ in blood
• B. High $C{O}_2$ content in blood
• C. High oxygen content in blood
• D. Low oxygen content in blood

Answer 1

Answer: (A)

Low $C{O}_2$ in blood

• Deep breathing rises the $O_2$ level of the blood. By excess formation of oxyhaemoglobin, the acidity of blood increases.
  
• To control it, more of free $C{O}_2$ changes into bicarbonate ions and the free $C{O}_2$ level in the blood decreases.
  
• So due to lack of stimulant for inspiratory centre cessation of breathing takes place, after some time, $O_2$ is consumed by the tissues and rise in $C{O}_2$ stimulates breathing again. So, the correct answer is option A.