The potential space enclosed by the layers of peritoneum in the abdomen is known as peritoneal cavity.
It is one of the cavities in the coelom; the others being the pericardial and pleural cavity. The space between the two membranes, parietal and visceral peritoneum, forms the cavity. The parietal membrane is the outer membrane, and visceral, the inner. These membranes are smooth, transparent, and semi-permeable, and form the lining of the abdomen.
This cavity is divided into two parts―greater sac and lesser sac. The greater sac is further divided into supracolic and infracolic compartments by the transverse colon. The supracolic compartment includes the liver, gallbladder, and stomach, whereas, the infracolic compartment consists of intestines. The lesser sac, or the omental bursa, is situated behind the stomach and opens into the cavity through the epiploic foramen.
It is located in the abdomen, the thoracic cavity being above it and the pelvic cavity below. It is present posterior to the diaphragm. The diaphragm separates the peritoneal and the pleural cavities.
Here's a diagram showing the peritoneal membranes and the various organs covered by the peritoneum.
Peritoneal Cavity Organs
The visceral peritoneum covers the organs that are suspended from the wall of the abdomen. Organs which are covered by the peritoneum and have supporting mesentery are known as 'intra-peritoneal organs'. The liver, spleen, gallbladder, transverse colon, and the small intestine are examples of intra-peritoneal organs. The organs which are only partially covered by the peritoneum and without supporting mesentery are the 'retroperitoneal or extraperitoneal organs'. They are the pancreas, kidneys, uterus, duodenum, bladder, and ascending and descending colon.
The cavity is closed in males, whereas in females, there is a connection between the cavity and the reproductive organs as the uterine tubes or the oviducts open laterally into the cavity. This is the main reason for women being at a high risk for peritoneal infections.
The peritoneum also contains a small amount of pale yellow lubricating fluid. About 50 ml of serous fluid is secreted per day. This fluid helps to reduce the friction between the organs present in the abdominal cavity. It contains white blood cells, antibodies, and some biochemicals. Sometimes the level of the fluid increases, and it leads to excess accumulation in the abdomen. This excess fluid is called ascitic fluid and the condition is known as ascites, which is a common cause of the liver disease, cirrhosis. Ascites symptoms may include increased abdominal girth, extreme fatigue, or shortness of breath. The fluid level can be maintained by water restriction or diuretics, which help in flushing out the excess body fluids through urine.
Peritoneal cancer, also known as peritoneal mesothelioma, is a rare type of cancer and is often confused with ovarian cancer. It remains unnoticed for a long period of time, until it becomes quite serious. This is because the symptoms are quite vague and difficult to make out. It is only when the symptoms become too severe that one realizes that he/she has fallen prey to it. The common symptoms are:
- Frequent urination
- Abdominal pain
- Loss of appetite
- Unexplained weight gain or loss
- Vaginal bleeding
The symptoms are more or less similar to that of ovarian cancer, and are often treated in the same way. The treatment depends on the stage of cancer and its intensity. Various forms of treatment like surgical removal of the tumor, chemotherapy, involving the use of various anti-cancer drugs, or radiotherapy are used. If the patient has reached the last stage of cancer, where there are practically no chances of recovery, palliative treatment is used. Peritoneal cancer can be treated effectively if it is detected at an early stage.
The peritoneal cavity plays an important role in the functioning of the digestive system by protecting and lubricating the various digestive organs.
Disclaimer: This article is for informative purposes only and does not in any way attempt to replace the advice offered by an expert on the subject.