Earlier this week many media outlets reported that a "new organ", the mesentery, had been discovered inside the human body. The story was covered by many national newspapers, including the Independent and MailOnline.
"Forget what you were told in biology class," wrote the Mail, "as researchers have classified a brand-new organ inside the human body." The Independent said it had been "hiding in plain sight".
The stories about the new discovery were based on a review article about the role of the human mesentery in health and disease, written by professors J. Calvin Coffey and D. Peter O'Leary at the University of Limerick, Ireland.
The review, published in medical journal The Lancet in November last year, gives reasons for why the mesentery, which is responsible for connecting the intestine to the abdomen, "should be subjected to the same investigatory focus that is applied to other organs and systems". The review also suggested that it should be viewed as one continuous organ, as opposed to the fragmented structure it is acknowledged as.
However, the headlines announcing that scientists have discovered a new organ were very misleading for a number of reasons. First, the mesentery was not discovered only recently – people have known about it for a very long time. For example, the mesentery was described by a professor at the Royal College of Surgeons, Frederick Treves, in a science article published by the British Medical Journal in 1885.
Second, the review article only suggested that the mesentery should be reclassified as an organ – whether it should or shouldn't be reclassified is still part of a scientific debate. So biologists on Twitter were understandably quick to respond:
Although it's controversial to say we've discovered a new organ, there's no doubt that the review plays an important part in our understanding of the human body. According the the authors, who wrote a blog post about their paper, the textbook Gray's Anatomy – one of the most famous human anatomy textbooks in the world – has been updated to include the new definition of the mesentery.
And, as the review also mentions, scientists are still in the early stages of understanding and detailing the various features of the mesentery.
A spokesperson from the British Society of Gastroenterology told BuzzFeed News it welcomes the review.
"The piece aims to stimulate and focus attention on the mesentery as a part of the abdomen – something previously studied infrequently," they said.
However, they also said that whether or not the mesentery should be considered an organ is still quite controversial, and there are many questions that need to be answered.
“The authors’ suggestion that the mesentery should be considered as an organ is certainly contentious at this point and there remain many unanswered questions such as whether the mesentery has a distinct functional unit, i.e. cell type," the spokesperson said.
They added: "Their review encourages much needed research. And helps other scientists to consider the role of the mesentery when studying diseases such as inflammatory bowel disease and conditions such as obesity."