Pulmonology: an area of medicine that focuses on the health of the respiratory system. Pulmonologists treat everything from asthma to tuberculosis. The respiratory system includes the organs that help you breathe. The three major parts of this system are the airway, the lungs, and the respiratory muscles. Pulmonologists are specially trained in diseases and conditions of the chest, particularly pneumonia, asthma, tuberculosis, emphysema, and complicated chest infections.