Introducing the Mesentery: Your Newest Organ

Medically reviewed by Daniel Murrell, MD on February 13, 2018Written by Jill Seladi-Schulman PhD on February 13, 2018

Overview

The mesentery is a continuous set of tissues located in your abdomen. It attaches your intestines to the wall of your abdomen and holds them in place.

In the past, the researchers thought the mesentery was made up of several separate structures. However, a 2016 article published in provided enough evidence to classify the mesentery as a single, continuous organ.

Keep reading to learn more about the structure of the mesentery and what its new classification as a single organ means for abdominal conditions, including Crohn’s disease.

Anatomy and function of the mesentery

Anatomy

The mesentery is found in your abdomen, where it surrounds your intestines. It comes from the area on the back side of your abdomen where your aorta branches off to another large artery called the superior mesenteric artery. This is sometimes referred to as the root region of the mesentery. The mesentery fans out from this root region to its locations throughout your abdomen.

mesentery

While the mesentery is a single structure, it has several parts:

  • Small-intestinal mesentery. This region is connected to your small intestine, specifically the jejunum and ileum regions. These are the last two regions of your small intestine before it connects to your large intestine.
  • Right mesocolon. This area of the mesentery runs flat along your posterior abdominal wall. Think of your posterior abdominal wall as the “back wall” of your body cavity.
  • Transverse mesocolon. This broad region of the mesentery connects your transverse colon to your posterior abdominal wall. Your transverse colon is the largest section of your large intestine.
  • Left mesocolon. Like the right mesocolon, this area of the mesentery also runs flat along your posterior abdominal wall.
  • Mesosigmoid. This region connects your sigmoid colon to your pelvic wall. Your sigmoid colon is the region of your colon just before your rectum.
  • Mesorectum. This part of the mesentery is connected to your rectum.

Function

The mesentery attaches your intestines to the wall of your abdomen. This keeps your intestines in place, preventing it from collapsing down into your pelvic area.

If the mesentery doesn’t properly form during fetal development, the intestines can collapse or twist. This than lead to blocked blood vessels or tissue death in the abdomen, which are both serious conditions.

Your mesentery also contains lymph nodes. Lymph nodes are small glands that are located throughout your body that help to fight off infections. They contain several types of immune cells and can trap pathogens, such as viruses and bacteria. Lymph nodes in the mesentery can sample bacteria from your intestines and generate an immune response when necessary.

Your mesentery can also produce a protein called C-reactive protein (CRP), which is a sign of inflammation. It’s usually produced in your liver, but fat cells in your mesentery can also produce it.

What does this mean for your health?

This new understanding of the mesentery and how it functions could be a game changer for how doctors understand and treat certain conditions. Crohn’s disease is a great example of this.

Crohn’s disease is a type of inflammatory bowel disease that causes inflammation of your digestive tract and bowel tissue. This inflammation can lead to pain, diarrhea, and trouble absorbing nutrients from food.

The mesentery of people with Crohn’s disease often has an increase in the amount and thickness of fat tissue. Fat cells in the mesentery can produce proteins that are associated with inflammation, including CRP. A linked this fat tissue in the mesenteries of people with Crohn’s disease to increased inflammation, CRP production, and bacterial invasion.

This connection suggests that targeting the mesentery might be an effective treatment option for Crohn’s disease. For example, a probiotic therapy was to improve inflammation-related dysfunction in mesentery tissue samples from people with Crohn’s disease. In addition, removing part of the mesentery may be an effective way to reduce the chance of Crohn’s disease returning after a bowel resection.

The bottom line

The mesentery is a newly classified organ in your abdomen. Researchers used to think it was made up of several parts, but recent research determined that it’s one continuous structure. This new understanding of the mesentery may help researchers better understand its role in certain conditions, including Crohn’s disease.

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