plague An infectious disease that is caused by the bacterium Yersinia pestis, which mainly infects rats and other rodents. Fleas function as the prime vectors for carrying Y. pestis from one species to another. Transmission of the plague to people can also occur if people eat infected animals, such as squirrels. When someone has the…
plague, sylvatic A type of plague that is spread by ground squirrels and other wild rodents. Sylvatic plague is sometimes seen in the western portion of the US.
plantar Having to do with the sole of the foot.
plantar response See Babinski reflex.
plaque 1 The white, semihardened substance that forms on the teeth as a result of bacterial action on food particles and provides an ideal environment for dental caries (cavities). 2 A semihardened accumulation of substances, including cholesterol, on the inner walls of blood vessels that can lead to blood clot formation, heart attacks, and strokes….
plaque, skin A broad, raised area on the skin. A skin plaque is broader than it is high.
plasma The liquid part of the blood and lymphatic fluid, which makes up about half of the volume of blood. Plasma is devoid of cells and, unlike serum, has not clotted. Blood plasma contains antibodies and other proteins. It is taken from donors and made into medications for a variety of bloodrelated conditions.
pinealoma An uncommon slow-growing tumor of the pineal gland. Also known as a pinealocytoma and pineocytoma.
pineoblastoma A fast-growing brain tumor in the pineal gland that originates in neuroepithelial cells. This malignancy is considered by many to be one of the primitive neuroectodermal tumors (PNETs). Also known as pinealoblastoma.
pineocytoma See pinealoma.
pinguecula A yellow spot on the conjunctiva (the membrane that lines the sclera—the “white” of the eye—and the eyelids) usually toward the inside of the eye, that is believed to be related to ultraviolet light exposure or other irritants. A pinguecula looks fatty and is due to an accumulation of connective tissue. Also known as…
pinguicula See pinguecula.