Dictionary

Body systems

Anatomy and the conditions of each body system, from the heart and lungs to the skin.

polyuriaPassing an abnormally large amount of urine, usually more than about 2.5 to 3 liters a day in an adult.

ponsThe part of the brain stem between the midbrain and the medulla.

post-traumatic stress disorderA mental health condition that develops after a person lives through or sees a terrifying event.

posteriorAt or toward the back of the body.

postpartumThe time after giving birth, usually the first six weeks, while the body returns to its non-pregnant state.

postpartum depressionDepression that starts during pregnancy or in the months after giving birth.

postpartum hemorrhageHeavy bleeding after birth: a total blood loss of 1,000 mL or more, or blood loss with signs of low blood volume, within 24 hours.

postpartum preeclampsiaPreeclampsia, a high blood pressure disorder of pregnancy, that begins or continues after the baby is born.

posturalRelating to the position of the body, such as lying, sitting or standing.

postureThe position in which a person holds the body when standing, sitting or lying.

PPROMPreterm premature rupture of membranes: the amniotic sac breaks before 37 weeks of pregnancy and before labor starts.

PR intervalThe part of an ECG from the start of the P wave to the start of the QRS complex.

Prader-Willi syndromeA genetic disorder that affects appetite, growth, muscle tone, learning and behavior.

prediabetesBlood sugar levels that are higher than normal but not yet high enough to be called diabetes.

preeclampsiaA disorder of pregnancy, starting after 20 weeks, that affects the blood vessels and organs such as the kidneys, liver and brain.

pregnancyThe time during which an embryo, then a fetus, develops inside the uterus, from conception to birth.

prelaborBefore labor begins.

preloadHow much the heart's ventricles are stretched by the blood filling them just before they squeeze.

prematureHappening before the expected or normal time, such as a baby born before 37 weeks of pregnancy.

premature rupture of membranesBreaking of the amniotic sac (the "water breaking") before labor has started.

premature ventricular contractionAn extra heartbeat that starts early from a ventricle instead of from the heart's normal pacemaker.

prenatalBefore birth; during pregnancy.

prenatal careHealth care for a pregnant person and the unborn baby during pregnancy, before birth.

presbycusisHearing loss that comes on slowly with aging, in both ears.

presbyopiaThe gradual loss, with age, of the eye's ability to focus on things up close.

presenting partThe part of the fetus that lies closest to the cervix and enters the birth canal first.

pressure injuryDamage to the skin and the tissue beneath it from pressure, or pressure with shear, usually over a bony area or under a device.

pretermBefore 37 completed weeks of pregnancy.

preterm laborLabor that begins after 20 weeks and before 37 weeks of pregnancy.

previaA Latin word meaning lying in front, used for something that lies over or near the cervix, ahead of the fetus.

probioticLive, helpful bacteria or yeasts taken in food or supplements to support the normal germs of the gut.

productive coughA cough that brings up mucus or sputum from the lungs.

progesteroneA female sex hormone that prepares the lining of the uterus for pregnancy and helps keep a pregnancy going, also given as a drug.

prognosisThe likely course and outcome of a disease, including the chance of recovery.

prolactinA hormone made by the pituitary gland that tells the breasts to make milk.

prolapseThe slipping or falling of an organ or part from its normal position.

prolonged decelerationA drop in the fetal heart rate of at least 15 beats per minute below baseline that lasts 2 minutes or more but less than 10.

pronationTurning the forearm so the palm faces down or backward; for the foot, rolling it so the weight is on the inner edge.

proprioceptionThe sense of where the parts of the body are and how they are moving, without looking.

prostaglandinA hormone-like fatty substance made in many tissues that acts on pain, inflammation, blood flow and uterine contractions; also drugs that copy it.

prostateA walnut-sized gland below the bladder in males that surrounds the urethra and makes part of the fluid in semen.

prostate cancerCancer that starts in the prostate, the gland below the bladder in males that helps make semen.

prostatitisInflammation of the prostate gland.

prosthesisAn artificial body part that replaces one that is missing or does not work, such as an artificial leg, joint, eye or heart valve.

prostheticDescribes an artificial part made to replace a missing or damaged body part, such as a limb, joint, eye or heart valve.

proteinA nutrient made of chains of amino acids that the body uses to build and repair tissue.

proximalNearer the center of the body, or nearer the place where a part is attached.

pruritusItching of the skin.

psoriasisA long-term immune-related skin disease in which skin cells grow too fast and pile up on the surface.

psychiatricRelating to psychiatry, the branch of medicine that diagnoses and treats mental illness.