Lung disease falls into two categories: obstructive disease and restrictive disease. Obstructive disease is one in which there is an increased resistance to the movement of air through the air passageways of the lung. An example of an obstructive disease is asthma, because the bronchioles are constricted. Increases in total lung capacity, functional residual capacity, and residual volume indicates obstructive pulmonary disease, because of the difficulty in getting air out through the constricted passageways. Restrictive disease is one in which total lung capacity is decreased, because of structural or functional changes such that the lungs do not expand as they should. An example of a restrictive disease is tuberculosis; indicated by decreases
