Narrator: What is COPD? Chronic obstructive pulmonary disease, or COPD for short, is a lung disease that affects millions of people. COPD includes diseases such as emphysema and chronic bronchitis. A person with COPD may have either emphysema or chronic bronchitis, but most have both. Some people with COPD may also have asthma-like symptoms, such as wheezing.

Let's take a look inside the lungs to see what is happening. First, look at the normal lung. The air sacks, or alveoli, look like grapes. Now, look at the air sacks of emphysema. In emphysema, there is damage to the walls of the air sacks, or alveoli, in the lungs. This results in a smaller number of normal air sacks, making it more difficult to transfer oxygen into the blood stream. Also, the lungs may not be able to get rid of carbon dioxide as well. Damaged lungs also lose their stretchiness (or elasticity). 

Look back at the normal airway. The airway's clear. Now, look at the airway of chronic bronchitis. In chronic bronchitis, there's a long lasting cough and mucus production. The airways in the lungs become swollen and produce more mucus.