The main function of the alveoli is gas exchange. The alveoli are part of the respiratory system, and are the smallest respiratory unit with the function of respiratory exchange. The main function of the alveoli is gas exchange, where oxygen absorbed through the alveoli is converted into oxygen-rich blood in the capillaries, and then transported to all parts of the body through the heart. In addition, while oxygen enters the blood through the alveolar capillary membrane, carbon dioxide, a metabolic product of the blood, also enters the alveoli through the alveolar capillary membrane, and is discharged with respiration, completing the gas exchange. In the human body, the lungs are a very important part, usually to do a good job of lung health. More exercise such as jogging and walking can strengthen lung function.