As for your surprise, now you have one more body organ than you realized, it’s Mesentery. As of 2016 November, mesentery is officially recognized as an organ of human body. The Lancet Gastroenterology and Hepatology have published the reclassification of this new body part.
As this has been official now, the anatomy that had been laid down for more than 100 years has been incorrect and false. To surprise you all, it has not been found that what exactly does this organ which hides out in our digestive system actually do.
As of Wikipedia, Mesentery Means, “a fold of the peritoneum which attaches the stomach, small intestine, pancreas, spleen, and other organs to the posterior wall of the abdomen.”