How COPD Affects the Lungs

COPD includes two conditions: chronic bronchitis and emphysema. Chronic bronchitis is an inflammatory condition that affects the amount of air that can reach the lungs through the airways (in particular, the bronchi and bronchioles). 

As you can see in the video to the left, in COPD, thick mucus is secreted by the linings of the bronchioles, restricting the flow of air in and out of the lungs. This may cause the alveoli to become enlarged, or hyperinflated, and the lung to actually grow in size. This makes it even harder to breathe.

Chronic bronchitis occurs when the tubes (the bronchi and bronchioles) that deliver air to the lungs from the windpipe become inflamed, usually after long-term exposure to cigarette smoke.

By moving the slider to the left, you can see how the linings of smaller bronchioles thicken, and excess mucus is produced. As the inflammation progresses, the bronchioles swell, and airflow is further restricted. This limits the amount of air that can readily enter, or leave, the lungs. 

Chronic bronchitis is marked by a persistent, productive cough. The cough is called “productive” because the patient coughs up sputum, or mucus, clearing the airways. Here you can see how the inflamed cells lining the bronchi produce excess mucus, and flood the airway with sticky secretions. The mucus overwhelms the hair-like projections, called cilia, which line the airways and help to filter out foreign particles. The muscles of the bronchi spasm, dislodging the mucus temporarily. But more mucus soon floods the lining of the airway, causing more coughing.

When you breathe, air enters the lungs and finds its way to tiny sacs called alveoli, in which a gas exchange takes place: your body takes in oxygen from the air and expel carbon dioxide. Elastic proteins in the connective tissue supporting the alveoli allow the alveoli to stretch when we breathe in, and resume their original shape when we exhale. However, in people with emphysema, the elastic tissues supporting the alveoli are damaged—typically as a result of long-term cigarette smoking. As you can see by moving the slider from left to right, over time the alveoli collapse and can no longer absorb oxygen effectively.

Normally, the elastic tissue of the alveoli (tiny sacs in the lung) enables them to stretch during inhalation, and return to their original shape during exhalation. This allows your body to absorb oxygen and expel carbon dioxide-filled air. But in emphysema (as you can see in the video to the left) the alveoli collapse on exhale, making them unable to effectively rid the body of carbon dioxide. This leads to the feeling of “shortness of breath” that characterize emphysema.

Unfortunately, the damage done to your lungs by smoking is irreversible. However, quitting is still the most important treatment for COPD—stopping today can halt the damage being done to your lungs.

Although there is no cure for COPD, treatments are available to help reduce the swelling and excess mucus production that are hallmarks of chronic bronchitis. While the permanent damage is irreversible, drug therapy may help reduce the production of mucus in chronic bronchitis, while anti-inflammatory drugs, such as corticosteroids, may help reduce inflammation in the airways.

Treating COPD requires a multifaceted approach. Although it is primarily a physical ailment, a diagnosis of COPD can change your life, and have ramifications on your emotional and psychological well-being.

To continue to maintain a high quality of life, it is essential to stay active, focused, and proactive. Visit Healthline’s COPD Center to learn more about living with chronic bronchitis and emphysema.