The lungs supply the organs and tissues of the body with oxygen. They are divided into areas called lobes: the right lung has three lobes and the left has two.
The lungs are covered by a lining called the pleura, which has two layers, and the inner layer covers the lungs. The outer layer is beside the ribcage and a muscle called the diaphragm, which separates the chest from the upper abdomen.

The lungs are part of our respiratory system, which includes:

  • the nose and mouth
  • trachea
  • tubes that lead to each lung (bronchi)
  • lungs

When we breathe,the air passes into the nose or mouth and goes through the trachea, where it splits into two airways that go down each side of the lung (bronchi).

The air passes through each of the bronchi and into the lungs through smaller tubes called bronchioles. At the end of the bronchioles there are tiny air sacs called alveoli. This is where the oxygen from the air we have taken inenters the blood and circulates throughout the body.
At the same time carbon dioxide goes from the blood into the alveoli. We rid ourselves of carbon dioxide when we exhale.