How do lungs work?
The lungs bring oxygen into the body and remove carbon dioxide. Air travels down branching airways to tiny air sacs called alveoli, where gases pass between the air and the blood.
When you breathe in, the diaphragm, a dome-shaped muscle under the lungs, tightens and moves down, while muscles between the ribs lift the chest. This enlarges the chest cavity and draws air in through the nose or mouth, down the windpipe and into the bronchi, which branch into smaller and smaller tubes called bronchioles.
At the ends of the bronchioles are about 300 to 500 million tiny air sacs, or alveoli, surrounded by tiny blood vessels. Oxygen passes through their thin walls into the blood, and carbon dioxide passes out to be breathed away. Spread flat, the alveoli would cover an area roughly the size of a tennis court.
Protecting the lungs
Tiny hairs called cilia and sticky mucus trap dust and germs, sweeping them out of the airways. Smoking damages these defenses and the alveoli. Regular exercise helps the lungs and breathing muscles work efficiently. Adults usually breathe about 12 to 20 times a minute at rest.
Did You Know?
The right lung is slightly larger than the left, which has a notch to make room for the heart.
This answer is general information, not medical advice. For a personal health question, talk to a doctor.