The actual exchange of gases takes place in the [[1]] of the lungs.

While breathing in and out, oxygen and carbon dioxide are exchanged between the blood and alveoli in the lungs. 

When oxygen is inhaled from the air, it gets to the body's tissues via the alveoli, blood, and tissues throughout the body.

The exchange of gases occurs in the lungs, between the alveoli and a network of small blood vessels called capillaries, which will be in the alveoli’s walls. 

Alveoli have thin and moist walls, which allows gaseous diffusion.