The lung becomes over-inflated and each breath must be forced out. Emphysema also destroys the walls of the alveoli severely compromising oxygen extraction and the lung's ability to expel the waste product carbon dioxide. Bronchiectasis scars the airways of the lung so that it is difficult to clear secretions. Infections are a common complication. Lung tissue is destroyed and breathing becomes difficult.
Pulmonary hypertension affects only the blood vessels in the lung.
The blood vessels constrict forcing the pressure in the pulmonary artery higher and higher. The heart can work against mild pressure increases but if the process continues the heart eventually fails and the delivery of oxygen to the rest of the body fails as well. Cystic Fibrosis is a genetic abnormality that results in viscous, thickened lung mucus. Abnormally thickened secretions are extremely difficult to clear from the lungs. Over many years, individuals with this disease become unable to maintain normal airways and suffer recurrent bronchial infections and pneumonia and bronchospasm.