Which system is primarily responsible for gas exchange in the body?

The respiratory system is primarily responsible for gas exchange in the body, a critical process that involves the intake of oxygen and the expulsion of carbon dioxide. This system includes the lungs, airways, and the muscular framework that facilitates breathing.

During respiration, oxygen from the air enters the alveoli in the lungs, where it diffuses into the bloodstream before being transported to the body's tissues. Simultaneously, carbon dioxide—a waste product of cellular metabolism—diffuses from the blood into the alveoli to be exhaled. This exchange is vital for maintaining the body's pH balance and overall metabolic function.

While the circulatory system also plays a crucial role by transporting gases to and from the lungs and the rest of the body, it does not directly facilitate gas exchange. Instead, it works in tandem with the respiratory system to ensure that the oxygen collected and carbon dioxide expelled are effectively delivered and managed throughout the organism. The nervous system regulates the process of breathing but is not directly involved in gas exchange itself, and the digestive system primarily deals with the breakdown of food and nutrient absorption, not gas exchange.