Dictionary

pump-oxygenator See heart-lung machine.

punch biopsy A biopsy that is performed by using a punch, an instrument for cutting and removing a disk of tissue. For example, a punch biopsy of the skin may be done to make a diagnosis of skin cancer.

puncture, ear See ear puncture.

puncture, lumbar See lumbar puncture.

puncture wound An injury that is caused by a pointed object that pierces or penetrates the skin. Puncture wounds carry a danger of tetanus.

pupil The opening of the iris. The pupil may appear to open (dilate) and close (constrict), but it is really the iris that is the prime mover; the pupil is merely the absence of iris. The pupil determines how much light is let into the eye. Both pupils are usually of equal size. If they…

purified protein derivative (PPD) The material used in the skin test for exposure to tuberculosis infection.

purine One of the two classes of bases in DNA and RNA. The purine bases are guanine (G) and adenine (A). Uric acid, the offending substance in gout, is a purine end product. See also pyrimidine.

purpura Hemorrhage (bleeding) into the surface of the skin. The area of skin with purpura is greater than 3 millimeters in diameter. The appearance of an individual area of purpura varies with the duration of the lesions. Early purpura is red and becomes darker, then purple, and brown-yellow as it fades.

psychotropic drug Any drug capable of affecting the mind, emotions, and behavior. Some legal drugs, such as lithium for bipolar disorder, are psychotropic. Many illicit drugs, such as cocaine, are also psychotropic. Also known as psychodynamic drug.

PTCA Percutaneous transluminal coronary angioplasty.

pterygium A wing-like triangular membrane. Although a pterygium can be anywhere, including behind the knee, it commonly refers to a winglet of the conjunctiva. This pterygium may extend across the white of the eye, toward the inner corner of the eye. It is caused by prolonged exposure of the eyes to wind and weather, or…