What defines emphysema in terms of lung structure?

Emphysema is characterized by the abnormal and permanent enlargement of the alveoli, which are the tiny air sacs in the lungs responsible for gas exchange. This enlargement occurs due to the destruction of the walls between the alveoli, leading to decreased surface area for oxygen and carbon dioxide exchange. As the structural integrity of the lung tissue is compromised, the efficiency of breathing diminishes, resulting in airflow limitation and difficulty in expelling air.

In emphysema, the loss of elastic recoil in the lungs makes it challenging for the individual to exhale fully. This condition is most often associated with long-term exposure to irritants, particularly cigarette smoke, which contributes to the degenerative changes observed in the alveolar structure. Understanding this fundamental aspect of emphysema is crucial for recognizing its implications on respiratory function and management strategies for affected patients.