Let’s take a look inside the lungs to see what is happening. The air sacs, also called alveoli, and the airways have been damaged in COPD, most often by cigarette smoking or certain agents in the environment. In the healthy lung, the air sacs or alveoli look like a bunch of grapes. Look at the alveoli of emphysema. In emphysema, the walls of the alveoli are partially destroyed. This results in a smaller total number of alveoli in the lungs. Fewer air sacs mean that the lungs are not able to transfer oxygen into the bloodstream as well. Also the airways may collapse a little.