Airway diseases include asthma, chronic obstructive pulmonary disease (COPD), bronchiolitis, and bronchiectasis (which also is the main disorder for persons with cystic fibrosis). People with airway diseases often say they feel as if they're "trying to breathe out through a straw.
The respiratory tract is the site of an exceptionally large range of disorders for three main reasons:
- it is exposed to the environment and therefore may be affected by inhaled organisms, dusts, or gases.
- It possesses a large network of capillaries through which the entire output of the heart has to pass, which means that diseases that affect the small blood vessels are likely to affect the lung.
- It may be the site of “sensitivity” or allergic phenomena that may profoundly affect function.