Exchange of gases takes place in the alveoli.
Exchange of gases in humans
Alveoli have thin and moist walls, which enable gaseous diffusion. Oxygen is transported from the lungs to the bloodstream during gas exchange. Carbon dioxide is transferred from the bloodstream to the lungs at the same time. It occurs in the lungs, between the alveoli and a network of small blood vessels known as capillaries, which are found in the alveoli’s walls.