Final answer:
Emphysema is a chronic lung disease in which the walls of the alveoli are damaged, leading to trapped air in the lungs and reduced gas exchange, usually caused by smoking tobacco.
Step-by-step explanation:
The presence of overdistended and nonfunctional alveoli is a condition called emphysema. Emphysema is a chronic lung disease that typically results from smoking tobacco, where the walls of the alveoli break down, leading to reduced surface area for gas exchange. This causes air to become trapped in the lungs after exhalation, decreases lung elastic recoil, and creates difficulties in breathing. In COPD (chronic obstructive pulmonary disease), emphysema refers to the specific lung changes associated with the disease, including the breakdown of connective tissues that reduces the number and elasticity of alveoli. Unfortunately, the damage to the alveoli in emphysema is irreversible.