Peritoneum

A thin sheet lines your belly. It wraps around your organs. This sheet has two layers. One layer sticks to your belly wall. The other layer wraps your organs. A tiny bit of slippery fluid sits between them. This fluid lets your organs slide easily. Some parts hang like an apron. This helps protect your insides. It is a very busy place!

The peritoneum is a thin sheet that lines your belly. It forms a lining for the space where your organs live. This sheet has two main parts. The first part is called the parietal peritoneum. It sticks to the inside of your abdominal wall. The second part is the visceral peritoneum. This part wraps around your organs to protect them.

There is a small space between these two layers. This space holds a tiny bit of slippery fluid. This fluid helps your organs slide easily when you move. Some parts of the sheet hang down like an apron. This is called the greater omentum. It hangs in front of your intestines. It can help protect or insulate your insides.

The peritoneum also helps hold things in place. It forms folds called mesenteries. These folds attach your organs to your body wall. They also carry blood vessels and nerves to your organs. This way, your organs get the power and signals they need to work. The sheet also has two main areas. One is the greater sac. The other is the lesser sac. They connect through a small opening.

The peritoneum is a thin, continuous sheet that lines your belly. It forms the lining for your abdominal cavity. This cavity is the space bounded by your muscles, diaphragm, and backbone. The peritoneum is very important because it supports your organs. It also acts as a path for nerves and blood vessels. This lining helps keep everything in the right place.

This sheet works in a special way using two layers. The outer layer is called the parietal peritoneum. It attaches firmly to your abdominal and pelvic walls. The inner layer is the visceral peritoneum. This layer wraps around your organs for protection. It is thinner than the outer layer. Between these two layers is a small space called the peritoneal cavity.

Inside that small space, there is about 50 mL of slippery fluid. This is called serous fluid. It allows the two layers to slide freely over each other. This helps your organs move without friction. Some parts of the sheet form folds called mesenteries. These folds attach organs to the abdominal wall. They also carry blood and lymph vessels to the organs.

There are many different parts within this system. The stomach and intestines are called intraperitoneal because they are wrapped in the lining. The kidneys are called retroperitoneal because they sit behind the space. The bladder is called subperitoneal because it is below the space. Some folds, like the greater omentum, hang down like an apron. This apron hangs in front of the intestines to protect them.

Doctors use different tools to see how the peritoneum is doing. A CT scan can show the spaces in just 15 seconds. MRI scans can also be used, but they take 30 to 45 minutes. Sometimes, people use peritoneal dialysis to help their bodies. This uses a glucose solution to absorb waste through the lining. The word peritoneum comes from Greek words meaning "stretched over."

The peritoneum is a continuous serous membrane. It lines the abdominal cavity, which is the space bounded by the vertebrae, abdominal muscles, diaphragm, and pelvic floor. This membrane is essential for protecting and supporting the organs within the body. It consists of a layer of mesothelium supported by a thin layer of connective tissue. The peritoneum also acts as a conduit. It provides a path for blood vessels, lymphatic vessels, and nerves to reach the organs.

The peritoneum is organized into two distinct layers. The outer layer is the parietal peritoneum. This layer attaches directly to the abdominal and pelvic walls. The inner layer is the visceral peritoneum. This layer wraps around the visceral organs to provide protection. The visceral peritoneum is thinner than the parietal peritoneum. Between these two layers lies the peritoneal cavity. This is a potential space that contains about 50 mL of slippery serous fluid. This fluid allows the two layers to slide freely over each other without friction.

Anatomists classify abdominal structures based on their relationship to this membrane. Intraperitoneal structures are wrapped in the visceral peritoneum. Examples include the stomach, the jejunum, the ileum, the cecum, and the appendix. These organs are generally mobile. Retroperitoneal structures are located behind the intraperitoneal space. The kidneys, adrenal glands, and most of the duodenum are retroperitoneal. These organs are relatively fixed in place. Some are primarily retroperitoneal, while others, like the duodenum, are secondarily retroperitoneal because they lost their mesentery during development.

Other structures are classified as subperitoneal or infraperitoneal. These are located below the intraperitoneal space. The urinary bladder and the distal ureters are examples of these structures. The peritoneum also forms complex folds known as omentums, mesenteries, and ligaments. These folds connect organs to each other or to the abdominal wall. The mesentery is a double layer of visceral peritoneum. It attaches the gastrointestinal tract to the posterior abdominal wall. It carries vital supplies like the superior mesenteric artery and various lymph nodes.

There are two main regions within the peritoneal cavity. These are the greater sac and the lesser sac. The two sacs communicate through a passage called the epiploic foramen. The lesser sac is divided into two parts called omenta. The lesser omentum attaches the liver to the lesser curvature of the stomach. The greater omentum hangs from the greater curvature of the stomach. It loops down in front of the intestines and then curves back up. It attaches to the transverse colon. This structure acts like an apron to insulate or protect the intestines.

The peritoneum has significant clinical importance in medicine. Doctors use imaging to assess the peritoneal spaces. A CT scan is a fast method that takes about 15 seconds. MRI scans provide detail but can take 30 to 45 minutes. Patients with certain conditions might not tolerate the long MRI process. Peritonitis is a serious condition involving inflammation of the peritoneum. It often results from an infection or chemical irritation from gastric acid. Treatment usually requires antibiotics and surgery.

In some medical treatments, the peritoneum is used to filter the blood. This process is called peritoneal dialysis. A glucose solution is sent through a tube into the peritoneal cavity. The solution stays there for a set time to absorb waste products. This works because the peritoneal cavity contains a high number of arteries and veins. Waste moves from the blood into the fluid through a mechanism called diffusion. The name peritoneum comes from the Greek words meaning "stretched over."