What is the main function of the lungs in the respiratory system?

The main function of the lungs in the respiratory system is gas exchange between air and blood. This process occurs in the alveoli, small air sacs in the lungs where oxygen from the air is absorbed into the blood, and carbon dioxide, a waste product of metabolism, is expelled from the blood to be exhaled.

This gas exchange is crucial for maintaining the body's oxygen levels and removing carbon dioxide, where hemoglobin in red blood cells binds to oxygen and transport it to tissues throughout the body. The efficiency of this gas exchange process is vital for sustaining cellular respiration, which is the mechanism through which cells generate energy.

While filtering air and moving air between the environment and the body are important functions associated with the respiratory system, they are secondary to the primary purpose of the lungs. Preventing respiratory infections is also a vital role of the overall respiratory system but is not a primary function of the lungs themselves. The lungs themselves serve primarily to facilitate the exchange of gases, which is essential for supporting life.