We all need to breathe. Bringing new air into the body and getting rid of old air and wasted gas is an essential part of daily living. And the lungs are a core component of this vital task.

The lungs are part of the respiratory system, and are divided into lobes or sections. The right lung has three lobes and the left lung has two lobes. You can think of each lobe as a balloon: It inflates when you breathe in and deflates when you breathe out.

Each lung sits next to the heart. They are safeguarded by a thin tissue called the pleura. Inside the lungs are millions of tiny air sacs called alveoli. These sacs — about 300 million total — are overlapped or interwoven by capillaries, which are fine blood vessels.