Dictionary

portal vein A large vein formed by the union of the splenic and superior mesenteric veins. The portal vein conveys venous blood to the liver for detoxification before the blood is returned to circulation via the hepatic veins.

portal hypertension An elevated pressure in the veins of the portal circulation. Normally, the veins from the stomach, intestine, spleen, and pancreas merge into the portal vein, which then branches into smaller vessels and travels through the liver. If the vessels in the liver are blocked, it is hard for the blood to flow, causing…

porphyria One of a variety of hereditary diseases that are characterized by abnormalities in the reactions needed for the production of heme, an essential substance for the body, resulting in increased formation and excretion of chemicals called porphyrins. Most porphyrias affect the skin or the nervous system. Attacks may range from mild to severe. Besides…

pork tapeworm See Taenia solium.

popliteal pterygium syndrome An inherited condition that is characterized by a web (pterygium) behind the knee. Facial abnormalities in popliteal pterygium syndrome are cleft palate (with or without cleft lip), pits in the lower lip, and fibrous bands in the mouth. Genital abnormalities in popliteal pterygium syndrome are underdevelopment of the labia majora, malformation of…

popliteal fossa The hollow behind the knee.

popliteal Referring to the back of the knee. For example, the popliteal fossa is the hollow behind the knee.

Pompe disease An inherited deficiency of the enzyme alpha-glucosidase which helps the body break down glycogen, a complex carbohydrate that is converted to glucose for energy. Without the enzyme, glycogen builds up in the heart and other muscles, causing extensive damage. There are several different forms of Pompe disease which vary in severity. Pompe disease…

polysomy Y syndrome See XYY syndrome.

polysomnography Electronic monitoring of a sleeping patient to look for abnormalities in sleep patterns and/or brain waves. Polysomnography correlates electroencephalogram readings with observation of the patient. Usually, respiration, oxygen saturation, body position, and other factors are also measured during polysomnography. See also sleep apnea; sleep apnea, central; sleep apnea, obstructive; sleep disorders.

polypsis of the colon See familial adenomatous polyposis.

polyps-and-spots syndrome See Peutz-Jeghers syndrome.