What is the main function of the respiratory system?

The main function of the respiratory system is to exchange gases, specifically to bring oxygen into the body and remove carbon dioxide from it. This process occurs primarily in the lungs, where oxygen from inhaled air diffuses into the bloodstream, and carbon dioxide, which is a waste product of metabolism, diffuses from the blood into the air in the lungs to be exhaled. This gas exchange is crucial for maintaining the body’s pH balance and supporting cellular respiration, which provides energy for the body's functions.

The respiratory system works closely with the circulatory system, but its primary role is not to circulate blood; that function belongs to the cardiovascular system. Additionally, the respiratory system does not digest food or produce hormones; those functions are associated with the digestive system and the endocrine system, respectively. Understanding the specific role of the respiratory system highlights its importance in sustaining life by facilitating essential physiological processes.