Gas Exchange in the Respiratory System: Where and How It Happens

Gas exchange occurs in the respiratory system in the alveoli, which are small air sacs located at the end of the bronchioles in the lungs. Oxygen from the air that is breathed in diffuses across the walls of the alveoli and into the bloodstream, where it binds to hemoglobin in red blood cells to be transported to the body's tissues. At the same time, carbon dioxide from the body's tissues diffuses into the bloodstream and is carried back to the lungs, where it is released into the alveoli and then expelled from the body during exhalation. This process of gas exchange is facilitated by the thin walls of the alveoli, which allow for efficient diffusion of gases between the lungs and bloodstream.