American Medical Association Family Medical Guide - American Medical Association [811]
perforation A hole in the wall of an organ or tissue caused by disease or injury.
perimenopause The transition phase that begins years before a woman’s last menstrual period during which the body begins to slow its production of estrogen.
peristalsis Wavelike contractions of muscles that move food and waste products through the digestive system. Occurs from the moment of swallowing to the elimination of waste from the rectum. Also transports urine from the kidneys to the bladder.
pharmacogenomics The study of how heredity affects the body’s response to drugs.
pheresis See apheresis.
phosphorus An essential mineral (found in food) that is important for strong teeth and bones and that plays a role in many processes in the body.
photophobia An abnormal sensitivity to or intolerance of light; the sensation that light is painful to the eyes. Photophobia is a symptom of some nervous system diseases and eye disorders.
photosensitivity An abnormal skin reaction to exposure to sunlight, usually in the form of a rash.
Photosensitivity may be a symptom of some disorders or a side effect of particular medications.
phototherapy Also called light therapy or ultraviolet light therapy. Treatment of disease by exposure to light, particularly by concentrated light rays or light of specific wavelengths. Sunlight is the most basic form of phototherapy.
placenta Also called the afterbirth (because it is expelled after the baby is born). The organ that develops in the uterus during pregnancy and nourishes a fetus; transfers oxygen from the mother’s blood to the fetus’s blood and removes waste products from the fetus’s blood to the mother’s blood for excretion by her lungs and kidneys.
plaque, arterial Also called atheroma. A patch of fatty tissue in an artery wall that can reduce blood flow or cause thrombosis.
plaque, dental A sticky coating on the teeth (made up of saliva, food particles, and bacteria) that can cause tooth decay and gum disease if not removed.
plasma The nutrient-filled, liquid part of the blood that remains after the blood cells have been removed.
plasma exchange See plasmapheresis.
plasmapheresis Also called plasma exchange. A procedure used to remove or reduce the amount of unwanted substances in the liquid part of blood (plasma). In plasmapheresis, blood is removed from a vein (usually in an arm) with a needle and tubing that is attached to a machine called a cell separator. The machine separates the plasma from the blood cells by spinning the blood at a high speed or by filtering the blood through a membrane; the plasma is discarded. The separated blood cells are then mixed with a plasma substitute and reinjected (usually into the other arm).
platelet Also called a thrombocyte. A blood cell fragment needed for normal blood clotting.
polyp A mushroomlike growth of tissue on the skin or on a mucous membrane.
polyunsaturated fat A type of fat (found in corn, sunflower, safflower, sesame, flaxseed, and soybean oils) that reduces total blood cholesterol level but may also lower beneficial HDL cholesterol.
postmortem See autopsy.
posttraumatic stress disorder A persistent disturbance of emotions and behavior that develops after experiencing extreme trauma, such as being the victim of or witnessing a violent crime.
postural hypotension Abnormally low blood pressure that occurs when a person sits up or stands suddenly.
potassium An essential mineral that helps the body maintain water balance, conduct nerve signals, contract muscles, and maintain a normal heartbeat.
precancerous Describes a condition that has the potential to become cancerous.
primary hypertension Also called essential hypertension. High blood pressure with no known cause.
progesterone A female sex hormone produced by the ovaries that is essential for a healthy pregnancy by promoting the growth and functioning of the placenta.
prolapse