Destruction of alveoli reducing gas exchange is characteristic of which condition?

• A. Emphysema
• B. Pneumonia
• C. Pulmonary Edema
• D. Congestive Heart Failure

Answer: (A)

Alveolar destruction lowers the surface area and disrupts the tiny air sacs where gas exchange occurs. In emphysema the walls between alveoli are damaged, creating larger, fewer alveolar spaces and losing much of the capillary network that normally surrounds them. That big drop in surface area for diffusion means less oxygen can move into the blood, and carbon dioxide less readily leaves it, especially with exertion. You also get loss of elastic recoil and air trapping, which further impairs effective ventilation.

Other conditions impair gas exchange differently. Pneumonia involves infection that fills alveoli with fluid and inflammatory debris, hindering exchange without destroying alveolar walls. Pulmonary edema and congestive heart failure involve fluid buildup in the interstitium or alveolar spaces, impairing diffusion, but not through destruction of the alveolar structures themselves.