pyoderma gangrenosum An ulcerating condition of skin that results in heaped borders with a typical appearance. Pyoderma gangrenosum appears to be mediated by the immune system, but the exact cause is unknown. The lesion usually begins as a soft nodule on the skin that then ulcerates. The ulcer enlarges, and the skin at the edge…
pyogenic arthritis Purulent arthritis with pus as a result of infection within the joint. See arthritis, septic.
pyrexia See fever.
pyrimidine One of the two classes of bases in DNA and RNA. The pyrimidine bases in DNA are thymine (T) and cytosine (C), and the pyrimidine bases in RNA are thymine (T) and uracil (U). See also purine.
pyuria Pus in the urine. Pyuria is a sign of inflammation, often related to infection.
pulmonary embolus A blood clot or foreign material that has been carried through the blood into the pulmonary artery or one of its branches, plugging the vessel.
pulmonary fibrosis Scarring throughout the lungs that can be caused by many conditions, such as sarcoidosis, hypersensitivity pneumonitis, asbestosis, and certain medications. Pulmonary fibrosis can also occur without an identifiable cause, in which case it is referred to as idiopathic pulmonary fibrosis. Symptoms include shortness of breath, coughing, and diminished exercise tolerance. Treatment involves use…
pulmonary function test A test that is designed to measure how well the lungs are working. Abbreviated PFT. PFTs gauge how the lungs are expanding and contracting (when a person inhales and exhales) and measure the efficiency of the exchange of oxygen and carbon dioxide between the blood and the air within the lungs.
pulmonary insufficiency A condition in which the valve between the right ventricle of the heart and the pulmonary artery is incompetent in its performance, allowing blood to slosh back from the pulmonary artery into the right ventricle.
pulmonary valve One of the four valves in the heart, which stands at the opening from the right ventricle in the pulmonary artery trunk. The pulmonary valve moves blood toward the lungs and keeps it from sloshing back from the pulmonary artery into the heart.
pulmonary vein One of four vessels that carry aerated blood from the lungs to the left atrium of the heart. The pulmonary veins are the only veins that carry bright-red oxygenated blood.
pulmonology The study and science of the anatomy, physiology, and pathology of the lungs.