Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «P»:
Pituitary adenoma: A benign tumor of the pituitary, the master gland that controls other glands and influences numerous body functions including growth. Although the tumor itself is not cancerous, it may affect pituitary function, and therefore may need to be removed. ...
Pituitary dwarfism: Dwarfism caused by a lack of
growth hormone, usually due to malfunction of the pituitary gland. Children with growth hormone deficiency may grow normally for the first two to three years of life but they then fall behind their peers in height. They are normally proportioned. Thi...
Pituitary gigantism: Excessive growth and too much height due to chronic overactivity of the pituitary gland which is located at the base of the brain. (Growth hormone is specifically made by the anterior pituitary gland.)
In pituitary gigantism, there is secretion of too much growth hormone before...
Pituitary gland: The main endocrine gland. It is a small
structure in the head. It is called the master gland because it
produces hormones that control other glands and many body functions
including growth. The pituitary consists of the anterior and
The anterior pituitary i...
Pituitary, anterior: The front portion of the pituitary, a small gland in the head called the master gland.
Hormones secreted by the anterior pituitary influence growth, sexual development, skin pigmentation, thyroid function, and adrenocortical function. These influences are exerted through the eff...
Pituitary, posterior: The back portion of the pituitary, a small gland in the head called the master gland.
The posterior pituitary secretes the hormone oxytocin which increases uterine contractions and antidiuretic hormone (ADH) which increases reabsorption of water by the tubules of the kidney....
Pityriasis alba: A mild form of eczema that occurs in young children and adolescents and produces mild patchy lightening and slight scaling of the skin of the face (particularly over the cheeks and around the mouth), the shoulders, or trunk.
The word "pityriasis" was used by the physician Hippocrate...
Pityriasis rosea: A common mild rash of unknown origin that can appear on a person of any age (most commonly at 10-35 years of age), may last from several weeks to several months, often begins with a "herald" patch, a large single pink patch on the chest or back and, within a week or so, more pink p...
PJS: Peutz-Jeghers syndrome....
PKD: Polycystic kidney disease....
PKU: Short for phenylketonuria. See: Phenylketonuria....
PKU, maternal: See Maternal phenylketonuria....
Placebo: A "sugar pill" or any dummy medication
For example, in a controlled clinical trial, one group may be given a real medication
while another group is given a placebo that looks just like it in order to learn if the differences observed are due to the medication or t...
Placebo effect: Also called the placebo response. A remarkable phenomenon in which a placebo -- a fake treatment, an inactive substance like sugar, distilled water, or saline solution -- can sometimes improve a patient's condition simply because the person has the expectation that it will be helpful...
Placebo response: A positive medical response to
taking a placebo, a sham medication as if it were an active medication. Up to
one-third of patients given a placebo may respond with a
reduction in symptoms, depending on the condition. This
phenomena is often laid to patients believing their