Question

Which chemical factor is most important in controlling respiration?

Answer 1

Respiration is the process which involves the breakdown of food by the oxygen. The oxygen is inhaled and the carbon dioxide is exhaled by the process of breathing. This exchange of gases takes place in the alveoli present in the lungs.

Complete answer:
The process of breathing involves intake of oxygen from the air and exhalation of carbon dioxide. The oxygen taken in is utilised by the muscles and the cells for the breakdown of food whereas the by-product of cellular respiration that is the carbon dioxide is exhaled to outside.
The respiration is controlled by the respiratory centre which is located at the stem of the brain known as medulla oblongata. The rate of respiration is dependent on the several factors like-
Chemical factors like carbon dioxide, oxygen and hydrogen ions. These are detected by the chemoreceptors which are located in the brain and the arteries and aorta. The carbon dioxide level increase stimulates the respiratory centre for more oxygen intake. Thus, the rate of respiration increases. The increase in the carbon dioxide concentration increases the hydrogen ion or low pH in the blood.
Body temperature- The increase in body temperature as in case of exercise increases the rate of respiration.
Thus, we can say that the rate of respiration is controlled by the carbon dioxide, oxygen and hydrogen ions.

Note-
The mechanism of breathing involves intake of oxygen through the nasal cavity. It reaches the lungs where the gaseous exchange takes place through the alveoli. The intercostal muscles in the diaphragm help in increasing the volume of the thoracic cavity.