The abdominopelvic cavity houses the majority of the digestive organs. Serous membranes, the same ones which line the abdominal cavity, cover the digestive organs and provide basic structural support. Simple squamous epithelium intermittently straddled with connective tissue creates the serous membranes. One of the main responsibilities of the serous membranes includes providing ample serous fluid lubrication for the digestive organs.
The visceral segment of the serous membranes encases the internal organs while the parietal segment is responsible for lining the body wall. Serous membranes which care for the needs of the lungs are known as pleurae while the serous membranes which care for the abdominal cavity are known as peritoneum, but are also referred to as peritoneal membranes. The entire abdominal cavity is lined by the parietal peritoneum. The back wall of the abdominal cavity contains the mesentery, which is where the parietal peritoneum folds over itself to create an existential fold. The mesentery serves both the gastrointestinal tract by giving it much needed support and more specifically serves the small intestine, permitting movement of the organ. The mesentery is where the vessels and nerves find their passage.
There is a specified segment of the mesentery which is designated to the support of the large intestine, which is known as the mesocolon. From there the peritoneal peritoneum becomes a continuation of the visceral peritoneum, starting with the encasement of the large intestine. These two peritoneum leave a space, which is deemed the peritoneal cavity. The adrenal glands, the pancreas,the abdominal aorta, the kidneys, and sections of the duodenum and the colon are considered to be retroperitoneal, meaning that these organs are found posterior to the parietal peritoneum. There are numerous extrusions from the parietal peritoneum, all of which are there to either help suspend organs from or anchor organs to the peritoneal cavity.
The liver is held to the abdominal cavity via the falciform, which is a serous membrane that has been reinforced with connective tissue. The greater omentum, which connects the stomach to the transverse colon, also forms a canopy of sorts over the small intestine. The greater omentum is responsible for the storage of fat, the support of various lymph nodes, providing protection in the event of an infection, and providing a cushioning for numerous visceral organs. In the event of significant but localized inflammation (such as appendicitis) the greater omentum is capable of sealing off the affected area to isolate the offending problem. The countering portion, the lesser omentum, traces along the lesser curvature of the stomach and finds its way to the upper duodenum until it finally reaches the inferior portion of the liver.