The intestine is a part of the digestive system of humans and animals, consisting of a number of tube-shaped organs located one after the other and interconnected (processes). In the body they perform digestive, transport and secretory functions.
The beginning of the intestine is called the duodenum in humans and animals, the cecum in higher animals, and the ileum in monkeys and rabbits. The cecum communicates with part of the colon and forms a vermiform appendix. It is the beginning of the midgut, the length of which exceeds the length of the entire upper and lower intestine combined. In the area of the junction of the middle and small intestines in humans, at the apex of the spleen, there is an omental opening that opens into the cavity of the omental bursa, which contains a large number of fat deposits. Often between the intestine and the lower end of the visceral layer of the mesentery there is a small blind growth - Meckel's diverticulum, which often becomes inflamed.
The length of the human intestine reaches an average of 7 m ± 3.5 m. A special feature of the structure of long sections of the intestine is the presence of longitudinal folds along it. They help maintain the shape of tubular organs. Thanks to longitudinal folds and growth along the long axis, the human intestine can reach sizes of up to 8.5 - 9 m. Both the human and animal intestines lack muscle layers, vessels and nerves. However, there are transverse folds with widening of the lumen (pockets), especially at the junction of the small intestine and the large intestine. The size and number of these sections can vary even within one person, depending on appetite. Large veins supply blood not only to the walls, but also to the branches and sections of the intestine.