Which two gases are primarily exchanged in the lungs?

The primary gases exchanged in the lungs during respiration are carbon dioxide (CO2) and oxygen (O2). This process occurs in the alveoli, tiny air sacs in the lungs where the exchange takes place. Oxygen is inhaled from the atmosphere into the alveoli, where it diffuses into the bloodstream. Simultaneously, carbon dioxide, which is a metabolic waste product produced by cells, diffuses from the blood into the alveoli to be exhaled. This exchange is crucial for maintaining proper levels of oxygen and carbon dioxide in the body, which is vital for cellular respiration and overall metabolic function. The understanding of this gas exchange process is foundational in anatomy and physiology, particularly in relation to respiratory health and function. Other gases listed, such as nitrogen, hydrogen, helium, and carbon monoxide, do not play a primary role in this essential exchange within the respiratory system.