What is one of the key characteristics of diseases like emphysema?

One of the key characteristics of diseases like emphysema is decreased lung capacity. Emphysema is a chronic respiratory condition that primarily affects the alveoli, which are the tiny air sacs in the lungs where gas exchange occurs. In emphysema, the walls of the alveoli become damaged and lose their elasticity, leading to an expansion of the air spaces in the lungs. As a result, the surface area for gas exchange is significantly reduced, which impairs the ability to breathe effectively and results in decreased lung capacity.

As the disease progresses, individuals may find it increasingly difficult to fully exhale air from the lungs, leading to air trapping and further reduction in functional lung capacity. This is an essential characteristic of emphysema and distinguishes it from conditions associated with increased lung elasticity or improved respiratory function. Other options, such as high infection rates, can occur in some respiratory conditions; however, they are not defining features of emphysema itself.