Hint: The longest component of the digestive system is the small intestine. It spreads to the big intestine (cecum) from the stomach (pylorus) and consists of three parts: duodenum, jejunum, and ileum. The small intestine mesentery is a large and long fan-shaped mesentery connected to the small intestine jejunum and ileum, linking them to the posterior abdominal wall.
The mesentery is a double fold of peritoneal tissue suspended from the posterior abdominal wall by the small intestine and large intestine. It was previously assumed to be a series of distinct structures, each with different insertions into the back wall. The mesentery, however, has been found to be one contiguous structure in recent studies, which has led to calls for its reclassification as an organ.
In the abdominal cavity, mesenteries are double layers of peritoneum and are continuations of the visceral and parietal peritoneum with the serous membranes adhered back to back in order to secrete serous fluid into the peritoneal cavity by the outer mesothelium. This eliminates the pressure between the adjacent visceral surfaces and encourages those organs that occur during digestion to pass.
The mesentery binds the intestines to the abdominal wall and also helps store the fat, enabling the intestines to be supplied by blood and lymph vessels, as well as nerves.
Note: A further layer of connective tissue known as Toldt's fascia is connected to the abdominal wall to the regions of the mesentery that are flattened against the posterior abdominal wall (the right and left mesocolon and the medial mesosigmoid). Several lymphatic channels comprise the fascia.