The body needs a constant supply of oxygen for a process called Cellular Respiration. Breathing in this oxygen allows the waste carbon dioxide to get out of the body.
Exchange of Gases Lungs are made up of clusters of alveoli. These are like large sacks, they have a large surface area and are kept moist. This is so the gas exchange can
They then lead on to the alveoli. The alveoli have a rich blood supply which maintains a concentration gradient in both directions. Oxygen is constantly removed from the lungs
and into the bloodstream. And the same happens but in vice versa for the carbon dioxide. This is called gas exchange. The membrane of these alveoli is also very thin, allowing the gas to