The human body is indeed a marvel. Many people do take health issues for granted and only worry when their health becomes really bad or when they feel pain that interferes with their ability to live freely everyday. Hence, it is important to take care of your health to prevent health issues from getting out of hand and to avoid suffering for a long time. In this article, we will be learning about a structure that plays an important role in supporting the organs in the body known as peritoneum.
The peritoneum is a thin membrane or flat pace of tissue that lines the abdominal and pelvic cavities. It is composed of a layer of mesothelium (a type of tissue derived from mesoderm) and supported by a thin layer of connective tissue. The peritoneum covers the internal organ inside the abdomen. It protects, cushions and holds the organ in place. The peritoneum produces a small amount of lubricant to lessen the friction when the organs brush against each other. The peritoneum supports the abdominal organs and acts as a passageway for lymphatics, nerves and blood arteries.
Peritoneum consists of two layers. The parietal and the visceral peritoneum. The parietal peritoneum lines the peritoneal cavity and the diaphragm (thin muscle below the lungs). Peritoneal cavity is the region between the abdomen and pelvis. The visceral peritoneum covers the external surfaces of most abdominal organs such as stomach, liver, spleen and parts of the intestines.
The peritoneum develops into highly folded and complex structures. The folds and spaces of part of the peritoneum are known as the three types of peritoneum. Below are the three types of peritoneum:
1) Mesentery- The double layer of visceral peritoneum. It connects some of the abdominal organs to the abdominal wall. It serves as pathways for the blood vessels, nerves and lymphatic vessels going in and out from the organ.
2) Omentum- The abdominal structures formed from peritoneum and structurally similar to mesentery. It extends from the stomach and part of the duodenum to other abdominal organs. Omentum is fatty tissue with prominent patches of fat that gives a lace-like appearance. The lesser omentum consists of a double layer of visceral peritoneum. It is formed from the liver to the lesser curvature of the stomach. The lesser omentum attaches the stomach and duodenum to the liver. The greater omentum consists of four layers of visceral peritoneum. It is formed from the greater curvature of the stomach then extends into the parietal peritoneum to form a large sheet that covers the intestines. The greater omentum attached the stomach to the transverse colon. The greater omentum is also known as the abdominal policeman due to the immunity role it possesses should there be any infection to the peritoneum.
3) Ligaments- Peritoneal ligament is a double fold of peritoneum that connects the organs to each other and attaches the intestine to the abdominal wall. For example, hepatogastric ligament connects the liver to the stomach.
The peritoneum may seem like a structure that is not important as many may not have heard about the words itself. It may not be as popular as heart diseases or kidney diseases but when there is damage or diseases affecting the peritoneum, it is difficult to treat and in some cases may easily lead to death. One of the importance of the peritoneum is the pain it exhibited. This is known as abdominal referred pain. Referred pain occurs when the brain is unable to pinpoint the source of discomfort due to the pain receptor receiving multiple different pain signals from different tissues. Referred pain is associated with the areas of the skin known as dermatomes supplied by the same sensory fibre along with part of the spinal cord. Thus, pain is referred to according to the embryological origin of the organ. For example, the pain from the foregut structures such as stomach, oesophagus and liver are referred to as an epigastric pain. Referred pain in appendicitis (inflammation of the appendix), may be confusing. The pain starts at the umbilical region (the belly button area) as it belongs to the midguts structures and is part of the visceral peritoneum but as the appendicitis gets more inflamed, it irritates the parietal peritoneum which cause the pain to be localised to the right lower part of the abdomen.
Another importance of understanding the peritoneum is the peritonitis disease. Peritonitis is defined as inflammation within the peritoneal cavity. It may indicate other gastrointestinal diseases such as spontaneous bacterial peritonitis causing ascites (build-up of excess fluid within the peritoneal cavity) from liver disease such as worsening cirrhosis. Beside this, peritoneal adhesion can occur as a result of infection, surgery or infection to the peritoneum. This causes formation of fibrous scar tissue that leads to abnormal attachment between the visceral peritoneum of the nearby organs or between visceral and parietal peritoneum.
In essence, the peritoneum plays an important role in the human body. Disruption or damages to the structures can lead to diseases that potentially lead to disability or even death when it is not treated early. Hence, symptoms such as pain in the abdomen should not be taken lightly and it is best to get medical advice when you are unsure what causes it.