The mesentery: A 'new' organ you didn't know you had
Ashley Strickland | 1/12/2017, 6 a.m.
(CNN) In case you've ever wondered what connects your intestine to your abdomen, there's a word -- and now, a single organ -- for that: the mesentery. But don't worry; you haven't grown a new organ. It's always been there, performing important functions that affect systems throughout the body, from cardiovascular to immunological.
Leonardo da Vinci depicted it as one contiguous organ, and it remained that way for centuries until 1885, when Sir Frederick Treves' findings presented the mesentery as fragmented amongst the small intestine, transverse colon and sigmoid colon.
The research of Dr. J. Calvin Coffey, foundation chair of surgery at the University of Limerick, is reclassifying this part of the digestive system as a contiguous organ. In a new study, Coffey has established the anatomy and structure of the mesentery, using images and compiling research to show that the organ's continuity can be seen only when it's exposed in a certain way.
The current findings resonate with those of Carl Toldt, who accurately described the presence of the mesentery in 1878. But his research was largely overlooked. At the time, Treves' findings supported the statements of Henry Gray, who mentioned multiple mesenteries in the 1858 first edition of his book "Gray's Anatomy," the go-to medical textbook for students around the world.
Coffey's research has already prompted the latest edition of "Gray's Anatomy" to refer to the mesentery as a continuous organ.
What does it do?
Linking your gut to the rest of your body is an important task, and the mesentery performs it well.
Among its functions, it carries blood and lymphatic fluid between the intestine and the rest of the body. It also maintains the position of the intestine so that it's connected with the abdominal wall without being in direct contact.
That connection is key.
"Without a mesentery to keep the intestine connected, the intestine would have to attach directly to the body wall," Coffey said. "It is unlikely that it would be able to contract and relax along its entire length if it were directly in contact. It maintains the intestine in a particular conformation, 'hitched up,' so that when you stand up or walk about, it doesn't collapse into the pelvis and not function."
Although researchers know that the mesentery plays an important role in the intestinal, vascular, endocrine, cardiovascular and immunological systems, more research is needed to determine the extent of those roles.
But they do have evidence that the mesentery takes environmental signals from the intestine and orchestrates the body's response, Coffey said. One example is how bacteria are sampled in the lymph glands in the mesentery. In response, the glands then coordinate immune responses.
Why has it been misunderstood?
To look at the shape of the membrane, which Coffey calls remarkable, it's easy to see why the mesentery has been depicted differently. It has a spiral formation in the abdomen and is packaged along a spinal trajectory, starting in the upper abdomen and ending in the pelvis.