What Is the Peritoneum?

The peritoneum refers to a layer of serosa in the abdominal cavity of higher vertebrates, which is mainly composed of mesothelial cells, and is a layer of membrane-like tissue formed by the support of connective tissue. The peritoneum covers most of the organs in the abdominal cavity, and can secrete mucus to wet the surface of the organs, reducing friction between the organs. The blood, lymph and nerve tissues of the abdominal organs are connected to the outside world through the peritoneum. The peritoneum also has the effect of absorbing and protecting the internal organs.

The peritoneum refers to a layer of serosa in the abdominal cavity of higher vertebrates, which is mainly composed of mesothelial cells, and is a layer of membrane-like tissue formed by the support of connective tissue. The peritoneum covers most of the organs in the abdominal cavity, and can secrete mucus to wet the surface of the organs, reducing friction between the organs. The blood, lymph and nerve tissues of the abdominal organs are connected to the outside world through the peritoneum. The peritoneum also has the effect of absorbing and protecting the internal organs.

Chinese name

peritoneum

Foreign name

peritoneum

Exist

Higher vertebrate abdominal cavity

Make up

Mesothelial cells

1 Peritoneum 1, anatomical structure of peritoneum:

The peritoneum is the largest serous membrane in the whole body and the most complicated cloth distribution. Its area is about the same as that of the skin. It consists of the mesothelium and the connective tissue outside it. It covers the inner surface of the abdominal wall and pelvic wall, as well as the surface of the abdominal cavity and pelvic organs. The former is called the parietal peritoneum or peritoneal wall layer, which is developed from the mesoderm of the body wall; the latter is called the visceral peritoneum or peritoneal viscera, which is composed of the visceral wall Mesoderm develops. The parietal and visceral layers migrate to form a highly irregular latent cavity called the peritoneal cavity. In men, the peritoneal cavity is a closed cavity, and in women, it can communicate with the uterus and vagina through the abdominal cavity of the fallopian tube. Due to the different sources of the parietal layer and the visceral layer, the nerve distribution is also different. The parietal layer receives 7 to 11 pairs of intercostal nerves, subcostal nerves, and lumbar nerves. The parietal central layer is dominated by bilateral sacral nerves. The layers are innervated by sympathetic nerves. Therefore, the parietal layer is sensitive to pain and other sensations, while the visceral layer is the opposite. However, due to the expansion of the organs, the nerve plexus, ischemia or smooth muscle spasm can also cause pain. Dirty peritoneum is thin, is closely connected to the organs, and is not easy to peel off, so it is often regarded as a component of the organs, such as the serous membrane of the stomach and intestines. The parietal peritoneum is thick, except that it is closely connected to the abdominal wall under the diaphragm, umbilical ring and ventral white line. It is separated from the abdominal and pelvic walls by a layer of loose connective tissue, called extraperitoneal tissue. Divided into the posterior abdominal wall, pelvic region and anterior abdominal wall, extra-peritoneal tissue contains more fat, which is particularly abundant in the posterior abdominal wall, and has the function of fixing and protecting posterior abdominal organs such as the kidney.

2 Peritoneal 2, physiological significance of peritoneum:

The peritoneum has functions of reducing friction, absorption, defense and repair. Under normal circumstances, a small amount of serum is contained in the peritoneal cavity, which can lubricate the peritoneal surface and reduce friction during internal organ activities. The peritoneum is rich in capillaries and lymphatic vessels and can absorb a large amount of isotonic fluid, blood or air. It is believed that the mesothelium has the ability to phagocytose, and the serous fluid also contains migrating macrophages, which can freely enter and exit the peritoneal cavity and surrounding tissues. The peritoneum has a strong ability to repair. Damage caused by hypoxia or other reasons can be repaired by connective tissue. If there is too much hyperplasia, it will cause adhesions.

3 Peritoneum 3, the relationship between the peritoneum and the abdominal and pelvic organs:

The abdominal and pelvic organs can be divided into three categories according to the area covered by the peritoneum, which are called intraperitoneal, interpositional and extrinsic organs. Endogenous peritoneum refers to all organs that protrude toward the peritoneal cavity, and their surfaces are almost covered by the peritoneum, such as the stomach, upper duodenum, jejunum, ileum, cecum, appendix, transverse colon, sigmoid colon, ovary, fallopian tube and spleen. Peritoneal organs refer to organs covered by peritoneum on three sides and without peritoneum on the other side, such as ascending colon, descending colon, upper rectum, liver, gallbladder, bladder, and uterus. Extraperitoneal (rear) organ means that the organ is only covered by the peritoneum in the front, and there is no peritoneum on the other sides, such as the lower and lower duodenum, middle rectum, pancreas, kidney and ureter.