It is composed of a layer of mesothelium supported by a thin layer of connective tissue. The peritoneum both supports the abdominal organs and serves as a conduit for their blood and lymph vessels and nerves.
The peritoneum (pron.: /ˌpɛrɨtənˈiəm/) is the serous membrane that forms the lining of the abdominal cavity or the coelom—it covers most of the intra-abdominal (or coelomic) organs—in amniotes and some invertebrates (annelids, for instance). It is composed of a layer of mesothelium supported by a thin layer of connective tissue. The peritoneum both supports the abdominal organs and serves as a conduit for their blood and lymph vessels and nerves.
The abdominal cavity (the space bounded by the vertebrae, abdominal muscles, diaphragm and pelvic floor) should not be confused with the intraperitoneal space (located within the abdominal cavity, but wrapped in peritoneum). The structures within the intraperitoneal space are called "intraperitoneal" (e.g. the stomach), the structures in the abdominal cavity that are located behind the intraperitoneal space are called "retroperitoneal" (e.g. the kidneys), and those structures below the intraperitoneal space are called "subperitoneal" or "infraperitoneal" (e.g. the bladder).
Contents [hide]
1 Structure
1.1 Layers
1.2 Subdivisions
1.2.1 Omenta
1.2.2 Mesenteries
1.2.3 Other ligaments and folds
2 Development
3 Clinical aspects
3.1 Peritoneal dialysis
3.2 Primary peritoneal carcinoma
4 Classification of abdominal structures
5 Etymology
6 Additional images
7 References
8 External links
[edit]Structure
[edit]Layers
Although they ultimately form one continuous sheet, two types or layers of peritoneum and a potential space between them are referenced:
The outer layer, called the parietal peritoneum, is attached to the abdominal wall.
The inner layer, the visceral peritoneum, is wrapped around the internal organs that are located inside the intraperitoneal space.
The potential space between these two layers is the peritoneal cavity; it is filled with a small amount (about 50 mL) of slippery serous fluid that allows the two layers to slide freely over each other.
The term mesentery is often used to refer to a double layer of visceral peritoneum. There are often blood vessels, nerves, and other structures between these layers. The space between these two layers is technically outside of the peritoneal sac, and thus not in the peritoneal cavity.
[edit]Subdivisions
There are two main regions of the peritoneum, connected by the epiploic foramen (also known as the omental foramen or foramen of winslow):
The greater sac (or general cavity of the abdomen), represented in red in the diagrams above.
The lesser sac (or omental bursa), represented in blue. The lesser sac is divided into two "omenta":
The lesser omentum (or gastrohepatic) is attached to the lesser curvature of the stomach and the liver.
The greater omentum (or gastrocolic) hangs from the greater curve of the stomach and loops down in front of the intestines before curving back upwards to attach to the transverse colon. In effect it is draped in front of the intestines like an apron and may serve as an insulating or protective layer.
The mesentery is the part of the peritoneum through which most abdominal organs are attached to the abdominal wall and supplied with blood and lymph vessels and nerves.
According to en.wikipedia.