Peritoneum (definition of)
The peritoneum is the mesothelial lining surrounding the organs of the abdomen, i.e., the gastrointestinal tract, liver, gall bladder, spleen, etc. Like the mesothelium of the heart and lungs (see pericardium and pleura), it is made up of two membranes: the visceral peritoneum which covers the internal organs themselves and makes up most of the outer layer of the intestinal tract, and the parietal peritoneum covering the abdominal wall. The cells of both layers secrete lymphatic fluid that acts as a lubricant the organs to move against one another, facilitating the smooth movement of the digestive track without chafing. Peritoneal mesothelioma, is a type of cancer that originates in the abdomen and is known only to be caused by asbestos exposure. Medical scientists believe that asbestos fibers are either injested and lodged in the peritoneum or inhaled through the lungs and lymph nodes. Learn more about peritoneal mesothelioma.