Dictionary

periphery 1 The outside or surface of a structure or the portion outside the central region. 2 The circumference of a circle or another geometric figure.

peristalsis The rippling motion of muscles in the digestive tract. In the stomach, this motion mixes food with gastric juices, turning it into a thin liquid.

peritoneal Having to do with the peritoneum.

peritoneal dialysis A dialysis technique that uses the patient’s own body tissues inside the abdominal cavity as a filter. A plastic tube called a dialysis catheter is surgically placed through the abdominal wall, into the abdominal cavity. A special fluid is then flushed into the abdominal cavity and washed around the intestines. The intestinal walls…

peritoneum The membrane that lines the abdominal cavity and covers most of the abdominal organs.

peritonitis Inflammation of the peritoneum, the membrane that lines the inner wall of the abdomen and pelvis. Peritonitis can result from infection, as by bacteria or parasites; injury and bleeding; or diseases, such as systemic lupus erythematosus. See also peritonitis, acute; peritonitis, chronic.

peritonitis, acute Sudden inflammation of the peritoneum that results in abrupt abdominal pain (acute abdomen). The most serious causes of acute peritonitis include perforation of the esophagus, stomach, duodenum, gallbladder, bile duct, bowel, appendix, colon, rectum, and bladder; trauma; intestinal obstruction; pancreatitis; vascular catastrophes (mesenteric thrombosis or embolism); and as an infectious complication of peritoneal…

peritonitis, chronic Longstanding inflammation of the peritoneum. Causes of chronic peritonitis include repeated attacks of infection such as from pelvic inflammatory disease, foreign substances such as talc, and chronic infections within the abdomen such as tuberculosis.

peritonsillar abscess A collection of pus behind the tonsils that pushes one of the tonsils toward the uvula. A peritonsillar abscess is generally very painful and is usually associated with a decreased ability to open the mouth. If left untreated, the infection can spread deep in the neck, causing airway obstruction and life-threatening complications.

pernicious vomiting of pregnancy See hyperemesis gravidarum.

personality disorder A disorder characterized by the long-standing use of mechanisms of coping in an inappropriate, stereotyped, and maladaptive manner. Personality disorders are enduring and persistent styles of behavior and thought, not atypical episodes. The personality disorders encompass a group of behavioral disorders that are different and distinct from the psychotic and neurotic disorders. The…

perspiration 1 The secretion of fluid by the sweat (sudoriferous) glands. These small, tubular glands are situated within the skin and in the subcutaneous tissue under it. They discharge fluid through tiny openings in the surface of the skin. Perspiration serves at least two purposes: It removes waste products such as urea and ammonia, and…