What happens to the lung in emphysema?
In emphysema, the walls of the air sacs (alveolar septae) are destroyed. Consequently, the individual air spaces (alveoli) become larger but irregular and decreased in number. These larger spaces are less efficient than normal sized alveoli for gas exchange. Thus, emphysema impairs diffusion of oxygen and carbon dioxide (gas exchange). The more extensive the emphysema, the poorer the gas exchange becomes. Also, in emphysema, the capillaries are destroyed with the rest of the alveolar wall. As a result, emphysema also disrupts the normal blood supply. Figure 4 contrasts the nasty appearance of a smoker’s emphysematous lung with a normal lung.