Intestine

The cavity in the bodies of multicellular animals serves the purpose of digestion and is part of the digestive system. Originally, this cavity was a simple hollow known as the primitive gut, with a connection to the outside world, as is the case with cnidarians. Later, this evolved into an external channel, the intestinal tract, which runs through the entire animal. This tract extends from a mouth opening to an anus opening, as is the case with bilaterians.

In a narrower sense, the section of the intestinal tract that begins behind the stomach and ends at the anus is called the intestine. Intestinal length varies depending on diet: in herbivores, the intestine is longer than in carnivores. For example, the intestine in cattle is 21 times as long as the body, while in cats it is only 4.5 times as long.

In the intestines, nutrients are extracted from the food pulp and released through the intestinal wall into the bloodstream for distribution throughout the body. The human intestine is 8-9 meters long in adults and is divided into the small intestine, large intestine, and rectum. It transports the food pulp, prepared in the stomach, to the anus through rhythmic contractions of its longitudinally and circularly arranged muscles.

In sheep, the duodenum, jejunum, and cecum are used for digestion. The duodenum and the sheep casing, are inserted without being turned inside out, with the mucous membrane, muscle layer and serous coatings removed.