COPD (chronic obstructive pulmonary disease) is a term used to describe long term conditions affecting the lungs, which causes breathing difficulties. COPD is mainly caused by smoking cigarettes. The two diseases that are responsible for almost all cases of COPD include:
Chronic bronchitis: develops when irritants are inhaled for a prolonged time, which inflames the tracheobronchial tree, leading to increased mucos production and a narrowed or blocked airway.
Emphysema: characterized by permanent enlargement of air spaces distal to the terminal bronchials. This leads to destruction of aveolar walls, which results in a break down of elasticity.