How are gases exchanged in the alveoli?

Gases are exchanged in the alveoli through a process called diffusion. Oxygen from the inhaled air passes through the alveolar membrane into the surrounding capillaries, where it binds to hemoglobin in red blood cells. Simultaneously, carbon dioxide in the blood diffuses from the capillaries into the alveoli to be exhaled. This exchange occurs efficiently due to the thin walls of the alveoli and the large surface area they provide.