The mesentery is an organ that attaches all the digestive organs in the abdomen. It connects much of the intestines to the back abdominal wall, holding them in place when a person stands upright.

The organ also contains lymph nodes, which affect the body’s immune response.

Various primary and secondary health conditions involve the mesentery. Primary conditions originate in the mesentery itself, while secondary conditions originate from other parts of the body.

Keep reading to learn more about the mesentery, including its functions and how it plays a role in some conditions.

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The mesentery is an organ from which all abdominal digestive organs form and connect. In addition to the small and large intestines, connected organs include the spleen, liver, and pancreas.

Researchers previously thought the mesentery comprised multiple but separate parts that connected centrally. However, recent studies show that below the duodenum — the first part of the small intestine — the mesentery is a continuous collection of tissue.

Organs in the abdomen and pelvis belong to either the mesentery domain or the non-mesentery domain.

Those in the non-mesentery domain are the genitourinary organs, such as the bladder and genitals. In other words, the mesentery serves to organize and connect the digestive organs while keeping them separate from the genitourinary organs.

The functions of the mesentery are as follows:

Attaches digestive organs

The mesentery attaches most of the intestines to the back abdominal wall, preventing them from entering the pelvis when a person stands. Without this connection, the movement of feces through the intestines would slow or stop.

Regulates immune response

The mesentery contains lymph nodes — small glands that filter lymphatic fluid — which help remove bacteria and waste products from the body.

Lymph nodes in the mesentery sample bacteria from the nearby intestine and regulate the immune response.

Produces C-reactive protein (CRP)

This substance regulates blood sugar and fat metabolism and contributes to inflammation regulation. Although the liver is the main source of CRP production, the mesentery fat cells also produce it.

Learn more about CRP levels.

Fosters tissue repair

The mesentery may play a role in tissue repair after surgery or following the development of various conditions.

The following disorders involve the mesentery:

Primary conditions of the mesentery

These conditions originate from the mesentery itself rather than sources outside the mesentery. They include:

  • Volvulus: This refers to the twisting of the mesentery and attached intestine.
  • Internal hernia: Gaps or defects in the mesentery may cause an intestinal hernia, which is a protrusion of the intestine through the surrounding tissues.
  • Non-rotation: During embryonic development, the mesentery may not rotate in a typical way, preventing proper attachment. It is the most common cause of death due to abdominal crises within the first 12 months of life.
  • Mesenteric cysts: These sac-like pockets of fluid are uncommon. They may not produce symptoms. However, if they bleed, a person can experience severe abdominal pain.
  • Blood vessel conditions: These are among the most common mesenteric conditions. Blockage of a mesentery blood vessel due to a blood clot or narrowing of an artery — likely due to plaque — can be very serious.
  • Cellular conditions: Examples of these are:
    • mesenteric lipodystrophy, an inflammatory disease affecting the fat in the mesentery
    • mesenteric panniculitis, the development of long-term inflammation and fat tissue in the mesentery, resulting in thickening and scarring of the tissue
    • immunoglobulin G4-related sclerosing mesenteritis, a condition that manifests in thickening and scarring of the tissue with the death of fat cells and inflammation
  • Mesenteric adenitis: This is the inflammation of lymph nodes in the mesentery, which causes pain in the right lower part of the abdomen.

Secondary conditions of the mesentery

The continuous connectedness of the mesentery with digestive organs means it can play a role in homeostasis. Homeostasis is the process that helps the body maintain a steady state. However, this connectedness is also a means of disease spread.

Secondary conditions originate from sources outside the mesentery and include:

  • Crohn’s disease: This condition causes inflammation and irritation, most commonly in the small intestine and the beginning of the large intestine. Wrapping and thickening of mesenteric fat typically occur in Crohn’s disease.
  • Intestinal cancer: Cancer in the intestine can move to lymph nodes in the mesentery, resulting in the spread of cancerous tumors outside the intestine.
  • Non-abdominal conditions: The mesentery is the biggest contributor to belly fat, which regulates the body’s CRP levels. When this protein is not under optimal regulation, it contributes to diabetes, obesity, narrowing of the arteries, and metabolic syndrome — a cluster of conditions that occur together.

The mesentery attaches all the digestive organs in the abdomen.

Functions include holding the intestines in place, helping regulate the immune response through lymph nodes, and producing C-reactive protein.

Some examples of primary conditions that affect the mesentery include volvulus, internal hernia, and mesenteric adenitis. Some examples of secondary conditions involve Crohn’s disease and the spread of intestinal cancer.