Mesenteries are double-layered serous membranes which attach to the loops of intestine, the stomach, and other abdominal organs. The serous fluid, together with the fat present, act as lubricants to prevent tearing and abrasion as these organs move within the cavity. The greater and lesser omenta are large fatty mesenteries which protect the organs. Similar double-layered membranes surround the heart as the pericardium, and the lungs as the pleural membranes. The peritoneal membranes line the peritoneal cavity and cover the organs.