Answer:
Increased blood levels of carbon dioxide
Step-by-step explanation:
Breathing is involuntary in nature which means it is not under our control. Respiration is regulated by both nervous and chemical means.
Nervous regulation involves:
a) respiratory rhythm center located in the medulla region of hind brain. It regulates respiratory rhythm according to the need of the body.
b) Pneumotaxic center is present in the pons region of hind brain. It reduces the duration of inspiration thereby altering the respiratory rate.
Chemical regulation:
There are certain chemosensitive areas which are sensitive for chemicals in the region adjacent to rhythm center. The chemoreceptors present here are sensitive to CO2 and H+ ions. These chemoreceptors gets activated when there is increase in CO2 and H+ ion concentration which in turn activates the respiratory rhythm center for altering the rate of respiration.
Increased CO2 in blood - the rate and depth of respiration increases
Decreased CO2 in blood - the rate and depth of respiration decreases