Final answer:
COPD is a lung disease caused by chronic poor airflow and is primarily caused by long-term exposure to tobacco smoking. Emphysema, a condition within COPD, results in the breakdown of lung tissues and reduces the surface area for gas exchange.
Step-by-step explanation:
Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by chronic poor airflow, resulting in shortness of breath and a productive cough. It is caused primarily by long-term exposure to tobacco smoking, which leads to the breakdown of connective tissues in the lungs. The walls of the alveoli, the tiny air sacs in the lungs, are destroyed in a condition called emphysema, reducing the surface area for gas exchange. As a result, the patient can no longer fully exhale air from the lungs, leading to low oxygen levels and an accumulation of carbon dioxide in the blood.