intestine is the digestive system in most vertebrates.Should he just behind the stomach.In the intestine is permanently adopted the digestion of food, absorption of nutrients, as well as the removal (evacuation) of undigested substances.
Some animals digestive tract consists only of that department.The length of the intestines depends on the species of animals, especially of food they consumed, and age.
most primitive closed structure of the department of digestion occurs in flatworms and cnidarians (colonial cnidarians).The latter has a single gastrovascular cavity through which the exchange of substances between individuals, which feeds, and other members of the colony.In flatworms there is one opening for food intake and excretion of waste.
invertebrates (insects, molluscs) have intestines, consisting of three sections (front, back and middle intestine).In the front part of the mouth included, goiter, pharynx, esophagus, located at the rear of the anus and rectum, in the middle - in fact, the intestine, Malpighian tubes, stomach.Some corals have eversible out the intestines.Digestion is thus carried out outside.
lamprey larvae-peskoroek and Amphioxus have enough direct and small intestine.The body begins immediately after the oropharyngeal cavity.The length of the small intestine of adult lampreys (no more than the body itself).Authority starts immediately after the esophagus has a valve in the form of a spiral.Through this helical longitudinal fold area increases absorption and digestion.Spiral valve is present in sturgeons and sharks.
Many length of the intestine of vertebrates allows to divide it into sections - a direct, large and small intestine.This body displayed the secrets of the pancreas and liver.At the beginning of the intestine bony fish are located pyloric caeca (blind process).Their number may be different.Amphibians are the duodenum, and opens into the cloaca of the rectum.
Land herbivorous reptiles have a well developed cecum.It is located on the border of the large and small department.The length of the intestine (small) birds several times the length of the body.From the rear division, which opens into the cloaca, it separates the two blind outgrowths.Rectum and colon not.
herbivorous animals have a long enough intestine.Blind and thick sections at the same time they are developed well enough.The length of the colon in rodents can reach 53% of the total length of the intestine.At predator it is much shorter.For example, a sheep intestines, longer than the length of the body in 29-35 times, wild boar - 14, horses - 12, and the wolf - in 6 Thick department occupies a symbiotic microorganisms, which have the most well-developed herbivorous.
intestine in humans is the largest organ of the digestive system.It starts from the stomach and ends at the anus (anus).Food moves through the mass of peristalsis (wavelike contractions).In the digestion process taking part located in the body and its constituent micro flora.In this area the gastrointestinal tract is done not only to the digestion, absorption and useful elements of the food, the synthesis of certain hormones, immune processes.
In life, the length of the intestine in humans (adult) is about four meters.At birth, she was about three meters, more than the average growth of the newborn to six times.The length of the human intestines after the death of increases and is about seven to eight meters.This is due to the relaxation of muscles after death.
