In emphysema, the alveoli are characterized as being over-_____ and under-______.

In emphysema, the alveoli are indeed characterized as being over-enlarged and under-ventilated. This condition leads to the destruction of alveolar walls, resulting in larger air spaces that do not effectively participate in gas exchange. The enlarged alveoli are unable to properly exchange oxygen and carbon dioxide due to a reduction in surface area and a decrease in the elasticity of the lung tissue.

The term "under-ventilated" accurately describes the impaired ability of these enlarged alveoli to facilitate appropriate airflow and gas exchange. This highlights the primary pathophysiological aspect of emphysema, where despite the increase in the size of the air spaces, the efficiency of breathing and oxygen transfer is compromised.

The importance of understanding this characteristic helps in recognizing the symptoms and complications associated with emphysema, as well as the interventions needed to manage the condition effectively.