The lungs

The lungs are part of our breathing (respiratory) system. Our lungs take in oxygen and supply it to our organs and tissues.

About the lungs

The lungs are the parts of the body that we use to breathe. They supply oxygen to the organs and tissues of the body. The lungs are divided into areas called lobes. The right lung has three lobes and the left lung has two lobes.

The lungs are covered by a lining called the pleura, which has two layers. The inner layer covers the lungs. The outer layer lines the ribcage and a sheet of muscle called the diaphragm. The diaphragm separates the chest from the upper tummy (abdomen).


Structure of the lungs and pleura
Image: Structure of the lungs and pleura




The respiratory system

The lungs are part of our respiratory (breathing) system. This system includes the:

  • nose and mouth
  • windpipe (trachea)
  • two tubes (bronchi) that branch from the windpipe to each lung
  • lungs.

The respiratory system

When we breathe in, air passes from our nose or mouth through to the windpipe (trachea). The trachea divides into two tubes (airways) that go to each lung. These tubes are called the right and left bronchus.

Air passes through each bronchus into the lungs through smaller tubes called bronchioles. At the end of the bronchioles, there are tiny air sacs called alveoli. This is where oxygen from the air we have breathed in (inhaled) passes into the blood. Then oxygen is circulated through the blood around the body.

A waste gas called carbon dioxide passes from the blood into the air sacs (alveoli). We get rid of carbon dioxide when we breathe out (exhale).

The lymphatic system

The lymphatic system helps protect us from infection and disease. It also drains lymph fluid from the tissues of the body then returns it to the blood.

The lymphatic system is made up of fine tubes called lymphatic vessels that connect to groups of lymph nodes throughout the body. Lymph nodes (sometimes called lymph glands) are small and bean-shaped. They filter bacteria (germs) and disease from the lymph fluid. When you have an infection, lymph nodes often swell as they fight the infection.

Sometimes, cancer can spread through the lymphatic system. If the cancer cells spread outside the lungs, they are most likely to go to lymph nodes nearby in the chest.


Lymph nodes close to the lungs