Which body system is responsible for breathing and supplying the body with oxygen?

The respiratory system is fundamentally responsible for breathing and supplying the body with oxygen. It consists of various structures such as the lungs, trachea, and diaphragm, which work together to facilitate the process of gas exchange. When air is inhaled, oxygen from that air enters the lungs and diffuses into the bloodstream, where it is transported to cells throughout the body. Simultaneously, carbon dioxide, a waste product of cellular metabolism, is exhaled from the lungs, highlighting the respiratory system's role in both supplying oxygen and removing carbon dioxide.

In contrast, the muscular system primarily focuses on movement; while it does play a role in the mechanics of breathing through muscle contractions, it is not responsible for the gas exchange itself. The circulatory system, composed of the heart and blood vessels, works to transport oxygenated blood throughout the body but does not directly handle the breathing process. The nervous system, while crucial for regulating both breathing and the overall function of the respiratory and circulatory systems, does not directly facilitate the intake of oxygen itself. Therefore, the respiratory system is the key player in supplying the body with the oxygen it needs for survival.