What Is Emphysema?

What Is Emphysema?

Emphysema is a lung disease that limits the movement of air into and out of your lungs, making breathing harder. Emphysema is most often caused by heavy, long-time cigarette smoking. Emphysema is one of a group of conditions called chronic obstructive pulmonary disease (COPD).

Healty airways with muscle, air sacs and blood vessels labeled.
Cross-section of healthy airways

Healthy Lungs

  • Inside the lungs are branching airways made of stretchy tissue. Each airway is wrapped with bands of muscle that help keep it open. Air travels in and out of the lungs through these airways.

  • The tubes branch into smaller passages called bronchioles. These end in clusters of balloon-like sacs called alveoli.

  • Blood vessels surrounding the alveoli absorb oxygen into the bloodstream. At the same time, the alveoli remove carbon dioxide from the blood. The carbon dioxide is then exhaled.

  • A dome-shaped muscle called the diaphragm lies below the lungs and is the main muscle used for breathing. The diaphragm flattens to draw air in as you inhale, and rises as you exhale.


Image showing cut away of collapsed airways, air sacs that have lost clustered shape and damaged blood vessels.

When You Have Emphysema

  • Airways become damaged. When the lung tissue gets baggy and loses its stretchiness, the surrounding airways collapse more easily and trap more gas in the chest. 

  • Damaged airways may collapse when you exhale, causing air to get trapped in the alveoli. This trapped air makes breathing harder.

  • Over time, the air sacs lose their clustered shape and drop out of these lung units. This may mean that less oxygen enters the blood vessels.

  • The alveoli enlarge and the diaphragm flattens. This makes it harder for the lungs to move air in and out.