Length of intestine
The intestine is the digestive systemin most vertebrates. It follows directly behind the stomach. In the intestine, the final digestion of the food taken, the absorption of nutrients, and the removal (evacuation) of undigested substances are carried out.
In some animals, the digestive tract consists only of this department. In this case, the length of the intestine depends on the type of animal, the characteristics of food used and age.
The most primitive closed structure of thisDepartment of digestion is observed in flatworms and coelenterates (colonial cnidaria). The second have a single gastrovascular cavity, through which there is a metabolism between the individual that feeds, and other members of the colony. Flatworms have one opening for food and waste disposal.
Invertebrates (insects, mollusks) possessintestine, consisting of three divisions (anterior, posterior and middle gut). The front part includes the mouth, goiter, pharynx, esophagus, in the back there is anus and rectum, in the middle - actually, intestines, Malpighian vessels, stomach. Some coral polyps have an outwardly curving intestine. Digestion, thus, is carried out external.
The larvae of lampreys and lancet haveenough straight and small intestine. The organ begins immediately after the oropharyngeal cavity. The length of the intestines of adult lampreys is small (not more than the body itself). The organ starts right after the esophagus, has a valve in the form of a spiral. Due to this screw-like longitudinal fold, the area of absorption and digestion increases. A spiral valve is present in sturgeons and sharks.
In many vertebrates, the length of the intestine allowsdivide it into sections - straight, thick and small intestine. This body displays the secrets of the pancreas and liver. At the beginning of the intestine of bony fish, pyloric appendages (blind processes) are located. Their number may be different. Amphibians have a duodenum, and a rectum opens in the cloaca.
The terrestrial herbivorous reptiles havewell developed cecum. It is located on the border of the thick and thin department. The length of the intestine (thin) of birds is several times the length of the body. From the back department, opening into the cloaca, it is separated by two blind outgrowths. Straight and large intestine no.
Herbivorous animals have enoughlong intestine. The blind and thick sections are well developed at the same time. The length of the large intestine in rodents can reach 53% of the total length of the entire intestine. Predators are much shorter. For example, a sheep has an intestine whose length exceeds the body length by 29-35 times, the boar in 14, the horse in 12, and the wolf in 6. The thick section is inhabited by a symbiotic microflora, which is most well developed in herbivores.
The human bowel is the largestbody of the digestive system. It starts from the stomach and ends with the anal opening (anus). The food mass is advanced by means of peristalsis (wave-like contractions). In the process of digestion, the microorganisms in the organ and its constituent microflora are involved. In this part of the digestive tract, not only digestion is carried out, but also the absorption of useful elements from food, the synthesis of individual hormones, and immune processes.
During life, the length of the intestine in a person (adult)is about four meters. At the time of birth, it is about three meters, which is more than the height of a newborn on average six times. The length of the human intestine after death increases and is about seven to eight meters. This is due to relaxation of the muscles after death.</ p>>