The structure of the thick and thin intestine

.


Colon. The structure and function of the large intestine.

Colonis the last section of the gastrointestinal tract and consists of six departments:
- The cecum (cecum, cecum) with an appendix (vermiform appendage);
- the ascending colon;
- transverse colon;
- descending colon;
- sigmoid colon;
- rectum.

General informationlength of large intestineis 1-2 meters, the diameter in the region of the cecum is 7 cm and gradually decreases to the ascending colon to 4 cm. Distinctive features of the large intestine compared with the thin are:
- the presence of three special longitudinal muscle bands or bands that begin near the appendix and end at the beginning of the rectum; they are located at an equal distance from each other (in diameter);
- the presence of characteristic swellings, which on the outside have the appearance of protrusions, and from the inside - bag-shaped depressions;
- the presence of processes of the serous membrane 4-5 cm long, which contain adipose tissue.

Mucosal cellsThe colon does not have villi, since the intensity of the absorption processes in it is significantly reduced.


ATthe large intestinesuction of water ends and feces are formed. For their formation and advancement of the large intestine by cells of the mucous membrane, mucus is secreted.

ATcolon lumenlives a large number of microorganisms with which the human body normally establishes a symbiosis. On the one hand, microbes absorb food residues and synthesize vitamins, a number of enzymes, amino acids and other compounds. In this case, a change in the quantitative and especially qualitative composition of microorganisms leads to significant disturbances in the functional activity of the organism as a whole. This can occur when the rules of nutrition - the consumption of large quantities of refined foods with low content of dietary fiber, excess food, etc.

Under these conditions, the so-calledputrefactive bacteria. in the process of vital activity, substances that exert a negative influence on a person. This condition is defined as a dysbacteriosis of the intestine. About it, we will tell in detail in the section devoted to the large intestine.

Fecal (fecal) massesmove along the intestine due to the undulating motions of the colon (peristalsis) and reach the rectum - the last department, which serves for their accumulation and excretion. In its lowest part there are two sphincters - inner and outer, which close the anus and open during defecation. The opening of these sphincters is normally regulated by the central nervous system. Desires for defecation in humans appear with mechanical stimulation of the receptors of the anus.

The structure of the intestine

Published by provizor on Tue, 06/08 / - 1: 8

.

Gastrointestinal tract of manis a complex system, the correct operation of which is vitally important for the organism. The intestine is located in the abdominal cavity, is responsible for digesting the ingested food, moving it, isolating the enzymes necessary for digesting, absorbing nutrients into the bloodstream. In addition, the intestine is the largest organ responsible for the immune system.

The structure of the intestine

The structure of the intestine includes 2 sections of the intestine - thick and thin. On any scheme of the intestine, they can be easily distinguished from each other. The average diameter of the small intestine is 3 cm, and the thickest - 4-10 cm. The length of the small intestine is 4 m, and the thickness - 2 m. The structure of the small intestine includes the 12-colon, the lean and ileum. The structure of the large intestine implies six departments. Divisions of the large intestine: the caecum; ascending, transverse, descending colon, sigmoid and rectum.

Intestinal walls

The structure of the intestinal wall includes 4 layers: mucous, submucosal, muscular and serous membranes. Each of these layers performs certain functions. For example, the serous membrane (located outside) produces a special fluid that moisturizes the abdominal cavity. Also there are stores of fat. The muscular membrane is responsible for peristalsis, and submucosal for the access of lymph and blood to the walls of the digestive canal. The work of the muscles of the intestines is affected by food, hormones and even the state of the nervous system. Useful bacteria in the intestines feed on the remains of undigested food and control the development of pathogenic bacteria. They must be present in sufficient quantities for the normal functioning of the whole organism.

Mucous membrane of the intestine

The structure of the intestine includes the intestinal mucosa located beneath all other layers and performing many tasks. Thanks to it, the digestion products are absorbed into the lymphatic and blood vessels of the intestine. The lymphatic nodules on it are responsible for protecting the body against infections. It is here that the enzymes necessary for digestion are developed, as well as mucus, moisturizing the food and protecting the surface of the digestive tract. On 1 sq. M. the mucosa of the small intestine is located 20-40 villi intestines, due to which the suction surface of the small intestine increases. There are no villi on the mucosa of the large intestine.

Glands of the intestine

The structure of the intestine implies the presence of special glands. The glands of the small intestine produce a digestive secret. These enzymes and those located on the surface of the intestine, contribute to the complete breakdown of food.

The digestive glands are not part of the large intestine. Existing glands produce mucus that promotes intestinal contents.

Intestinal cells

Intestinal cells are called enterocytes. The bulk of the cells are constricted, enterocytes, which are responsible for absorption and parietal digestion. Goblet cells produce mucus. 1% of cells, the location of which is in the small intestine, are acidophilic enterocytes, which contain digestive enzymes. There are also beskamchatye cells, which can multiply, and also turn into limb and goblet enterocytes. Be careful that you do not have enterocolitis of the intestine.

Small intestine. Departments, the structure of the wall of the small intestine

Small intestine(lat. intestinum tenue) - a section of the intestine in vertebrates, located between the stomach and the large intestine. The small intestine carries out the main function of absorbing nutrients from the chyme in the animals. The relative length and features of the structure of the small intestine largely depend on the type of nutrition of the animal.

The small intestine is divided into a human by a duodenum (lat. duodenum), skinny (lat. jejunum) and iliac (lat. ilium), with the lean forming 2/5, and the iliac 3/5 of the entire length of T. gut, reaching 7-8 m (from 472 cm to 1055, and on average 64 cm)

Twelve # 76; bowel # 769;(lat. duodénum) - the initial section of the small intestine in humans, the next immediately after the pylorus of the stomach. The characteristic name is due to the fact that its length is about twelve diameters of the finger of the hand.

The duodenum is closely anatomically and functionally connected with the pancreas and the biliary system. On the inner surface of the descending part of the duodenum there is a large duodenal papilla (), into which, through the sphincter of Oddi, a common bile duct and pancreatic duct (in most, but not in all-papillae, people fall into the common bile duct, but some go separately). Above the fecer papilla 8-40 mm can be a small duodenal papilla, through which an additional (santorium) pancreatic duct opens (this structure is anatomically is variable).

The duodenum has a special histological structure of the mucosa, making its epithelium more resistant to aggressiveness as gastric acid and pepsin, and concentrated bile and pancreatic enzymes than the epithelium of the more distal parts of the fine guts. The structure of the epithelium of the duodenum is also different from the structure of the epithelium of the stomach.

One of the main functions of the duodenum is to bring the pH of the food gruel from the stomach to alkaline, non-irritating more distal parts of the small intestine and suitable for the implementation of intestinal digestion. It is in the duodenum that the process of intestinal digestion begins. Another important function of the duodenum is to initiate and regulate secretion pancreatic enzymes and bile, depending on the acidity and chemical composition of the food mush.

The third most important function of the duodenum is to maintain feedback from the stomach - the implementation of reflex opening and closing of the pylorus of the stomach, depending on the acidity and chemistry of the incoming food pulp, as well as regulation acidity and peptic activity of secreted gastric juice through the secretion of humoral factors affecting the secretory function stomach.

That # 76; bowel # 769; human # 76; a(lat. jejunum) - the middle section of the small intestine, going after the duodenum and in front of the ileum. The name "skinny" comes from the fact that the dissection of the corpse anatomists found it empty.

The loins of the jejunum are located in the left upper part of the abdominal cavity. The jejunum is covered with peritoneum on all sides. The jejunum, unlike the duodenum, has a well-defined mesentery and is considered (together with the ileum) as a mesenteric part of the small intestine. There is no clearly defined anatomical structure dividing the skinny and ileum. However, there are clear differences between these two parts of the small intestine: the ileum has a larger diameter, its wall is thicker, it is richer provided with blood vessels. The jejunal loops lie mainly to the left of the median line, the ileum loops - mainly to the right of the median line. The mesenteric part of the small intestine is covered in front on a greater or lesser extent by an omentum.

The jejunum is a smooth-muscular hollow organ. In the wall of the jejunum there are two layers of muscle tissue: external longitudinal and internal circular. In addition, smooth muscle cells are present in the intestinal mucosa.

The length of the jejunum in an adult reaches, m. Women are shorter than men. In a living person, the gut is in a tonic tense state. After death, it stretches and its length can reach, m.

Acidity in the jejunum is neutral or slightly alkaline and is usually within 7-8 pH.

Motor activity of the jejunum is represented by various types of contractions, including peristaltic and rhythmic segmentation.

Podvzdo # 76; bowel # 769; human # 76;(lat. ileum) - the lower part of the small intestine, going after the skinny and in front of the upper part of the large intestine - with the caecum, which is separated from the last ileocecal valve (Baugner's valve). The ileum is located in the right lower part of the abdominal cavity and in the region of the right ileal fossa.

The ileum is covered on all sides by the peritoneum. The ileum, unlike the duodenum, has a well-defined mesentery and is considered (together with the jejunum) as a mesenteric part of the small intestine. There is no clearly defined anatomical structure that separates the ileum and jejunum. However, there are clear differences between these two parts of the small intestine: the ileum has a larger diameter, its wall is thicker, it is richer provided with blood vessels. The jejunal loops lie mainly to the left of the median line, the ileum loops - mainly to the right of the median line.

The ileum is a smooth-muscular hollow organ. In the wall of the ileum there are two layers of muscle tissue: external longitudinal and internal circular. In addition, smooth muscle cells are present in the intestinal mucosa.

The length of the ileum in an adult reaches, m. Women are shorter than men. In a living person, the gut is in a tonic tense state. After death, it stretches and its length can reach, m. The internal diameter of the gut is about 27 mm.

Acidity in the ileum is neutral or slightly alkaline and is usually in the range of 7-8 pH.

Motor activity of the ileum is represented by various types of contractions, including peristaltic and rhythmic segmentation

Structure of the small intestine:

The intestinal mucosa

Circular muscle layer

Longitudinal muscle layer

Inner surfacesmall intestinecovered with small outgrowths, which increases the suction area. Ifsmall intestineis an overloaded toxin, the speed and efficiency of the digestive process is reduced. In this case, the gut simply can not perform its physiological functions.

Sources: http://meduniver.com/Medical/Physiology/450.html, http://provizor.org/stroenie-kishechnika, http://allrefrs.ru/5-19493.html



.



No comments yet!

Share your opinion