What characterizes the pathophysiology of emphysema?

The pathophysiology of emphysema is primarily characterized by the destruction of alveolar walls. In emphysema, the alveoli—tiny air sacs in the lungs where gas exchange occurs—become damaged and lose their elasticity. This destruction leads to a decrease in surface area available for gas exchange and the formation of larger, less efficient air spaces. As the alveolar walls break down, they fail to hold their shape during exhalation, causing air to become trapped in the lungs and resulting in difficulty breathing. Patients often experience symptoms such as shortness of breath and reduced exercise tolerance due to this compromised respiratory function.

In contrast, the other options describe characteristics that may be associated with other respiratory conditions. Increased mucus production, inflammation of the lungs, or constriction of blood vessels can occur in diseases such as chronic obstructive pulmonary disease (COPD) or asthma, rather than specifically defining emphysema's distinct pathological changes.