Definition: thin sheet of tissue that lines the peritoneal cavity and secretes serous fluid, ehich serves as a lubricant and facilitates free movement between organs. Classified as parietal (portion of lining that forms a closed sac) and visceral (portion of lining that directly covers organs and various body structures). Characterized as intraperitoneal (inside the sac) and retroperitoneal (posterior or behind the sac).
Example: structures enclosed and generally covered by peritoneum inclue the liver, gallbladder, spleen, stomach, majority of the intestines, and ovaries. Structures behind and only anterior surfaces are covered by peritoneum include the pancreas, inferior vena cava, abdominal aorta, urinary system, colon, and uterus.