The Lungs and Breathing

The cells of the body have a constant requirement for oxygen to power the various metabolic reactions that release energy from ingested nutrients to produce ATP. In the process of cellular metabolism carbon dioxide is created as a waste product, which if not eliminated accumulates in the body and dangerously lowers the pH of the tissues and blood, which inhibits a myriad number of vital chemical reactions.  The primary method by which we obtain oxygen and eliminate carbon dioxide is respiration.