Emphysema is characterized by which of the following?

Emphysema is a chronic respiratory condition that primarily affects the lungs, specifically the alveoli, which are the small air sacs responsible for gas exchange. The hallmark of emphysema is the enlargement of air spaces due to the destruction of the walls between the alveoli. This destruction leads to a reduction in the surface area available for gas exchange and results in the characteristic symptoms of shortness of breath and reduced airflow.

In this condition, the elastic fibers that help maintain the structure of the alveoli are damaged, leading to an inability to properly exhale air from the lungs. This causes air to become trapped, contributing to the enlargement of the air spaces. Therefore, option C accurately describes the pathophysiology of emphysema, making it the correct answer.

Other options, while they represent various lung conditions or issues, do not accurately depict the primary characteristics of emphysema. For example, constriction of the airways is more related to conditions such as asthma or chronic bronchitis. Blockage of the alveolar ducts and fluid accumulation in the lungs are more indicative of other pathologies like pulmonary edema or pneumonia. Understanding the specifics of emphysema helps clarify why enlargement of the air spaces and destruction of the alveolar walls