Asthma is due to a decrease in airflow in the major airways of the lungs. It can be caused by muscle spasms in the airways, swelling of cells lining the airways and excess mucus in the airways. The other two chronic obstructive pulmonary diseases are chronic bronchitis and emphysema.
Chronic bronchitis is caused by small abnormalities in the airways.
Emphysema is caused by destruction of the alveolar walls. All rights reserved.