Corticosteroids—A class of drugs, related to hormones naturally found in the body, that suppress the immune system. One example is prednisone, sold under many brand names including Deltasone.
End-stage lung disease—The final stages of lung disease, when the lung can no longer keep the blood supplied with oxygen. End-stage lungs in pulmonary fibrosis have large air spaces separated by bands of inflammation and scarring.
Farmer's lung—An allergic reaction to moldy hay, most often seen in farmers, that results in lung disease.
Inflammation—The body's reaction to an irritant, characterized by the accumulation of immune cells, redness, and swelling.
Lung function tests—Tests of how much air the lungs can move in and out, and how quickly and efficiently this can be done. Lung function tests are usually done by breathing into a device that measures air flow.
Mucous membranes—The moist coverings that line the mouth, nose, intestines, and other internal organs.
Pulmonary artery—The blood vessel that delivers blood from the heart to the lungs.
Sarcoidosis—A disease of unknown origin that results in clumps of immune cells and inflammation in organs throughout the body.
Anna Rovid Spickler D.V.M., Ph.D., The Gale Group Inc., Gale, Detroit,