A membrane located in the human digestive system has been upgraded as an organ. The mesentery — previously known as a group of membranes by most scientists — is now known as a single structure and is considered an organ. The reclassification of mesentery brings the number of human organs to 79.

Previous anatomy books have noted that the mesentery is composed of fragmented membranes. Instead of being thought of as a whole, scientists once thought that these were different mesenteries located in different parts of the intestines.

What - And Where - Exactly Is The Mesentery?

The mesentery serves as a connection between the intestines and the abdomen. It contains several folds of tissues that serve as an anchor for the intestines within the abdominal wall. The organ begins from the rectum down to the small intestine located at the base of the stomach. Without the mesentery, the intestines would simply juggle around in the belly.

History Of The Mesentery

Interestingly enough, this is not the first time that the mesentery has been thought of as a single unit. Italian polymath Leonardo da Vinci identified the membranes as a single, contiguous structure. But then Sir Frederick Treves came along. The English surgeon was known for having treated Edward VII by draining an abscess in the royal's appendix.

Many of his peers considered Treves an expert when it came to matters of the gut. In his studies and talks, Treves presented the mesentery as a fragmented portion of the intestines that existed only sporadically, failing to give it any importance.

How The Mesentery Was Established As A Single Organ

In a study published in The Lancet, Dr. J. Calvin Coffey, professor at the University of Limerick's Graduate Entry Medical School in Ireland, found that Treves's study was false, and that the mesentery is its own continuous organ.

For Dr. Coffey, mesenteric science is now its own field of medical study in the same way that gastroenterology and neurology are.

"Up to now there was no such field as mesenteric science. Now we have established anatomy and the structure," he said.

Dr. Coffey also believes that the next step is determining the full function of the mesentery.

"If you understand the function you can identify abnormal function, and then you have disease. Put them all together and you have the field of mesenteric science, the basis for a whole new area of science."

Implications Of The Mesentery's Reclassification

The reclassification could change the way abdominal diseases are treated. Knowing how our digestive system works will lead to better understanding and treatment of abdominal diseases such as Crohn's and irritable bowel syndrome.

There is also a host of other diseases that affect the mesentery.

• Mesenteric artery ischemia narrows the arteries and prevents oxygen-rich blood from reaching the intestines.

• Mesenteric panniculitis is the inflammation of the fatty tissues within the mesentery, which causes scarring and fibrosis.

• Mesenteric lymphadenitis is the inflammation of the lymph nodes that attach the intestines to the abdominal wall.

"When we approach it like every other organ, we can categorize abdominal disease in terms of this organ," said Dr. Coffey, who believes that having better understanding of the mesentery's nature will lead to less invasive surgeries and faster patient recovery.

Gray's Anatomy, the most famous medical textbook, has already been updated with the reclassification.