The lungs

Lungs do three specific things :

1, inhalation, bringing air into the lungs by contracting the diaphragm and intercostal muscles, which expands the chest cavity, pulling air into the lungs.

2, when air is in the lungs the oxygen is absorbed by red blood cells and taken around the body. When it has run out blood comes back to the lungs and this repeats.

3, exhalation pushing carbon dioxide from the blood into the lungs and breathing it out.

The Alveoli (or air sacs) are about 2-3 cells thick and let air into the blood and CO2 out of the body

The surface area of your lungs is about the size of half a tennis court!