How are oxygen and carbon dioxide exchanged in our body during respiration?
Gaseous exchange in our body takes place in the alveoli of lungs. The oxygen of air diffuses out from the alveoli walls into the blood. As the blood passes through the tissues of the body, the oxygen present in it diffuses into the cells. This oxygen combines with the digested food present in the cells, to release energy. Carbon dioxide gas, which is produced as a waste product during respiration in the cells of the body tissues, diffuses into the blood. Blood carries the carbon dioxide back to the lungs, where it diffuses into the alveoli.