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What is Mesentery?

The mesentery is a dual fold of membrane of peritoneal tissues that join the intestine to the abdominal wall and clasp it in place. Peritoneal tissues are found in the abdominal wall and coat the organs in the abdomen. Peritoneal fluid acts as a lubricant on the surface of the tissues. Earlier it was assumed mesentery to be made of separate structures, each with discrete attachment to the posterior abdominal wall. But recent findings reveal mesentery to be a homogeneous structure, thus re-nomenclature as an organ. 


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The root of mesentery extends from the duodenojejunal flexure to the ileocaecal joint. The root of mesentery is about 15cm long, traversing a third of the duodenum, the aorta, the inferior vena cava, the right ureter and the right gonadal arteries. The root of mesentery split the infrasonic compartment into upper (right) infrasonic space and lower (left infracolic space). The infracolic compartment consists of loops of small bowls estranged by ascending and descending colon from the paracolic gutter on both sides. 

The root is the tip where the mesentery fastens to the posterior abdominal wall, thus a bare area. The root of mesentery is long, contracted, slanting, originating from the left side of the L2 vertebra to the right of the sacroiliac seam, crisscrossing various abdominal organs.

Anatomy 

The pelvic region consists of the rectum, bladder, and genital organs, seminal vesicle, prostate in males, and uterus in females. The answer to what is mesentery is it is an organ that attaches the intestine to the abdominal wall made up of peritoneal tissues. Mesentery in small intestine keeps the intestine in place, preventing downfall to the pelvic region. It also stores fat conduit blood and lymph vessels and nerves to the intestines and permits some movement for digestion.  

Though mesentery is a contiguous structure, mesentery anatomy can be named according to viscera related to it. It originates from the back of the abdomen, where the aorta divides into another significant artery known as the superior mesenteric artery, also called the root of the mesentery. The mesentery branches off to different locations all the way through the abdomen holding small and large intestine and still allowing some movement. Mesentery tissues are made of peritoneal tissues that drape the pancreas and small intestine and extend down to the colon and upper portion of the rectum.

Different Parts of the Mesentery are:

  • The mesentery of the small intestine

  • Right mesocolon

  • Transverse mesocolon

  • Left mesocolon

  • Mesosigmoid

  • Mesorectum

Supplementary layers of connective tissues (Toldt's fascia) attachment of mesentery to the posterior abdominal wall.

Functions

The main mesentery function is to attach and uphold the intestine to the abdominal wall stopping falloff to the pelvic region. If the organ does not grow during fetal development, the intestine can get deformed or collapse. Consequently, the blood supply can stop or tissue death occurs both are adverse medical conditions. Contents of mesentery are lymph nodes which are small glands that combat infection. Lymph nodes are also found throughout the body. Lymph nodes located in the mesentery screen bacteria and produce immune responses whenever necessary. Mesentery also produces a protein named C-reactive (CRP), a symptom of inflammation; fat; fat cells embedded in the mesentery are also capable of producing this protein.

Dorsal mesentery facilitates movement, located between the pharynx and anus. It can be subdivided into caudal foregut, midgut and hindgut. The structure of dorsal mesentery is complex and broad due to the asymmetrical and strong growth of the stomach. It is a conduit to the gut for blood supply, nerves and lymphatics. In the area of the duodenum, it is called the dorsal mesoduodenum, and in the area of the colon, it is known as dorsal mesocolon. In an embryo of about thirty-seven days old, the foregut is attached to the posterior body by the dorsal mesentery.

Mesentery vs Omentum

The abdominal cavity and its organ play a major role in metabolic activities. The gastrointestinal cavity starting from the mouth ending at the anus is the most vital organ in the abdominal cavity. The mesentery and omentum are the two most supportive tissues present in the gastrointestinal tract. The mesentery tissues are embedded in the intestine, while omentums are resultant fat tissues playing a crucial role during infection or inflammation and located in front of the intestine. Omentum is a serous membrane of the peritoneum protecting the abdominal cavity and encompassing organs, which can be categorized into greater and lesser omentum.

Thus, this well-written article has extensively covered all the vital information regarding mesentery and what it does for your body. 

FAQs (Frequently Asked Questions)

1. What is the Significance of Mesentery?

The understanding and functionality of mesentery is a game-changer in medical science. Crohn's disease is a classic example. People suffering from Crohn's disease experience pain, diarrhoea and are unable to absorb nutrients from food due to infection in the digestive tract and bowel tissues. Patients suffering from this ailment have thick fat tissues on their mesentery. Excessive fat tissues in mesentery can produce proteins, including CRP, which can result in inflammation and bacterial infection. This association shows targeting mesentery tissues can be an effective way to treat Crohn's disease. Probiotic therapy to readdress dysfunction mesentery tissues can reduce inflammation, or surgery of affected mesentery portion can reduce the probability of recurring Crohn's disease after bowel resection.


2. What is Omentum?

Omentum is a layer of fatty tissues hanging from the stomach and liver, causing the intestine and other organs. It plays a crucial role in immune response and metabolism, though its complete function ability is not fully comprehended. As it has no discrete function, its importance can be easily overlooked. But it interacts with organs in intricate and vital ways. Most of the action takes place on a cluster of white blood cells encompassing the organ known as the milky spot. It acts as a screening system of the fluids that circulate through the omentum and plays a role in triggering an immune response. When foreign microbes are detected, the milky spots activate inflammatory molecules to mount a defence.


3. What is Mesenteric Panniculitis?

Mesenteric panniculitis is a chronic disease that affects the fat cells of the mesentery. It causes relentless inflammation, which can damage or demolish fat cells. This can lead to scar tissues and other symptoms. There are three phases of mesenteric panniculitis:

  • Mesenteric lipodystrophy is when fat cells are reinstated by cells from the immunity system.

  • Mesenteric panniculitis, in this stage, more immunity cells invade and replace fat, mesenteric cells resulting in inflammation.

  • Retractile mesenteritis when inflammation aggravates and scar tissues start to generate in the mesentery.

Though mesenteric panniculitis is not a life-threatening disease, symptoms can make daily life complicated. The exact cause of this disease is unknown, but it is an autoimmune ailment where regular cells are identified harmful by the immunity system and start attacking them, causing inflammation, scar tissues and other symptoms.


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