Asthma is a lung disease that creates inflamed, constricted bronchi (the major airways leading to each lung). The constriction results from contraction of the smooth muscles surrounding the airways. The inflammation stimulates excess mucus production. Because of these and other symptoms, asthma often resembles chronic bronchitis, a form of chronic obstructive pulmonary disease or COPD. However, there are differences between asthma and bronchitis.
