The departments of the colon, its structure and functions

The organism is very complicated and at the same time surprisingly harmonious. Among the systems that ensure its vital activity, there is one that processes incoming substances from food, extracts the most useful of them, and gets rid of waste, all without the conscious participation of the person himself. The large intestine, whose structure and functions will be examined in more detail, is part of this mechanism. What do we know about him?

Gastroenteric tract

Every organism needs energy to maintain its vital functions. It can be obtained in many ways. For example, in humans, as in many other animals, for this purpose there is a gastrointestinal tract and, in general, the digestive system.

This part of the body is arranged quite difficult and is responsible for the complete processing of all incoming substances, maximum recovery of useful and disposal of residues. It all begins in the mouth, because it is here that food initially comes from. First, it is thoroughly crushed and mixed with saliva, which immediately starts the primary cleavage, and then falls into the stomach. Here, with the help of various substances, further treatment of the intake and absorption of carbohydrates, parts of water, ethanol and certain salts takes place.

The next stage is the small intestine. Here, the main digestion of food occurs, the breakdown of carbohydrates, proteins and fats to simpler constituents and their absorption for transport and delivery to cells. This is possible due to the special structure of the mucosa of this organ. The fact is that the internal surface of the intestine is covered with microvings - villi, which significantly increases the area of absorption. Also this department is an important part of the hormonal system, because here there is a synthesis of some peptide hormones that regulate the activity of the entire gastrointestinal tract and immune processes.

And, finally, the last stage of the gastrointestinal tract is the large intestine. The structure and functions of this organ should be considered separately and in detail, because they are no less interesting than the rest of the digestive system. And, of course, they are also very important.

Characteristics of the large intestine

Its name was given to this section of the digestive tract due to the fact that its internal lumen is larger than that of the previous part. It is curious that this is noticeable only when the dead body is opened, while in the live one the diameter of the large intestine and the thin are practically the same or differ only slightly. Nevertheless, this department of the gastrointestinal tract has a broader layer of muscle fibers and connective tissue. But all the same, the terms "thin" and "large intestine" are absent in the anatomical nomenclature and are considered to be incorrect.

The length of this organ is usually from 1 to 1.6 meters, the average diameter is about 6.5 centimeters, the exact figures depend on the specific part. Well, if we talk about the structure of the large intestine, then its walls consist of serous and muscular tissue, there is also a submucosa and the mucous membrane itself, which is lined with an internal cavity of the organ. There are no villi, but there is a large number of crypts - depressions of the epithelium, which promote better reabsorption.

Circulatory circulation of the colon is provided by the inferior and superior mesenteric artery. For the innervation meet the fibers of the vagus and spinal nerves. The outflow of blood is provided by the mesenteric veins.

Location:

The large intestine, the anatomy of which was described in general form a little earlier, begins after the buginia flap that separates the ileum and the cecum. This structure does not allow the reverse movement of chyme - gruel, obtained due to digestion of food.

Further the intestine passes upwards and to the left, encircling the previous department of the digestive tract, and then again descends, ending with the anus. Through it occurs the evacuation of feces, that is, the body gets rid of unnecessary remnants. However, sometimes the rectum is isolated separately from the thick one. In this case, the last section becomes the part called sigmoid.

Functions

The large intestine does not belong to physiologically active organs. Usually the main purpose of this body is the formation of stool and the disposal of the body. In fact, the functions of this body are wider.

First, it is here that the extraction of nutrients is completed. Everything useful that it was impossible to digest earlier is processed. For example, only at this stage can be extracted fiber. Also, residues of water and salts are almost completely sucked out of the chyme.

Secondly, the large intestine of a person is an important part of the immune system. Here there are colonies of bacteria of different types, mostly anaerobic. Some of them help digestion, others prevent the spread of pathogens, others produce enzymes that help the body work properly, as well as vitamins K, E, B ₆ and B ₁₂ , necessary for the whole body. In a word, the microflora of the large intestine is an important part of the protective barrier of the human body. And it is so powerful that it can cope even with single cancer cells, completely destroying them.

Thirdly, it is the structure of the large intestine, in particular its muscular layer, that provides a constant movement of digested food. In this case, a person can not even control it. The speed of peristalsis is usually constant and increases after a new portion of food enters the stomach. Thus, the muscles of the colon are responsible for maintaining a more or less constant speed of the food "conveyor".

Despite the fact that the gastrointestinal tract can cope with almost everything a person uses as food, do not thinklessly throw in yourself anything. Disrupt the work of the intestine is not difficult, and it can not be noticed right away. And when symptoms of his improper work appear, it can be very difficult to restore the balance, so it's better to stick to a healthy diet with enough fiber that perfectly stimulates the digestive tract.

Divisions of the large intestine: an overview

Traditionally, three main parts are distinguished: the blind, colon and rectum. Each of them also has its own sub-departments, which makes the structure of the body quite complex, with virtually no differences in function.

So, an appendix is attached to the cecum. The colon is divided into ascending, transverse and descending, as well as sigmoid sections. Finally, even in a straight line there is a separation into an ampulla and an anal canal with an anus. And each part has its own characteristics. Therefore, it is worth talking about the departments of the large intestine more. All of them are interesting in their own way.

Cecum

This department is located in the right ileal fossa and has the appearance of an almost round sac measuring about 6 x 7-7.5 centimeters. It is here that the thin and large intestines border. They are separated only by a small valve.

The main function that this part of the large intestine performs is the absorption of water from the incoming diet. In general, the structure of this department does not differ from the rest. By the way, it is here that the upper mesenteric artery closes as closely as possible to the intestine. Separating into a large number of branches, it is responsible for the blood supply to most of it.

Appendix

From the cavity of the cecum through a narrow passage, one can get into its appendage, an important one, though not a full-fledged department. It's about the appendix, or the appendix. For a long time it was believed that this is only a rudiment, since man is one of the few mammals along with rabbits and monkeys who have this part. Experiments were conducted during which children were given appendectomy, that is, they removed this appendage at an early age. As a result, many of them had serious problems with immunity.

Today it is believed that the appendix is a kind of farm for beneficial bacteria that colonize the intestines. Because of its special structure, almost no food is available. In addition, people with distant appendicitis find it extremely difficult to restore the microflora and to regulate the intestine, for example, after taking antibiotics. Nevertheless, it still remains a rudiment, since before taking the present species, it was a full-fledged part of the gastrointestinal tract and took part in digestion.

Unfortunately, operations to get rid of this process are carried out quite often. Appendicitis firmly ranks first among acute surgical operations. Over a year, 4-5 cases per 1000 people are recorded. With an early application for medical care, the outlook is favorable. The risk of death is extremely small, but increases if it is a perforation, as well as in the presence of such a factor as the elderly.

Colored

Just behind the cecum goes the next department, which is conditionally divided into 4 parts. The first of them - the ascending one - goes up the right side to the liver and ends with a smooth curve. The next sub-unit is the transverse colon. As it follows from its name, passes from right to left through the peritoneum. It also ends with a bend leading to the descending part, going from top to bottom along the left side. Sigmoid colon (the last part of this department) is located in the left ileal fossa. Its name was received as an S-shape.

Like other parts of the large intestine, this part is mainly responsible for the absorption of water and electrolytes and the formation of more solid contents from the chyme. After the mass is formed, colored in a dark color by the enzymes of the gallbladder and consisting of substances that are not necessary to the body, the epithelium exfoliated, etc., it proceeds further.

Straight

This is the last part of the intestine, the main task of which is to accumulate solid masses and remove them from the body. It is completely located in the cavity of the small pelvis and ends with the anal opening. It is curious that defecation is a complex physiological process controlled by the cerebral cortex, while in children at an early age it is purely reflex.

Normally, stool masses make up about a third of everything that was eaten. The frequency and quantity can vary depending on the diet and lifestyle. However, usually emptying the rectum occurs every day, and while the person gets rid of waste with a mass of 200 to 500 grams.

Methods of research

One of the most common complaints at any age is the pain in the abdomen. Quite often it's only a matter of increasing the pressure inside the intestine, for example, due to the accumulation of gases or simply spasms. Nevertheless, this body requires an attentive attitude towards itself, and therefore, if it is suspected that it is not working properly, it is worthwhile to contact the doctors, especially if the problems appear frequently.

An important role in the diagnosis is played by an anamnesis. The doctor can ask about the localization and features of the pain, frequency and nature of the chair recently, the diet.

The second method of investigation is palpation. The doctor probes the organs through the anterior abdominal wall, fixing the patient's complaints, paying attention to the tension of the muscles, etc. This helps in the first place to establish foci of soreness.

Also, the patient's stools are often used. Analysis of the chemical, macro- and microscopic, as well as bacterial composition can give an understanding of many processes occurring in the large intestine. For example, problems with microflora are diagnosed in this way.

To assess the suction function, X-rays can be used with contrast agents.

Finally, colonoscopy is also used if it is necessary to get a complete picture of what is happening in the intestine. With this study, a probe with a camera and a lamp at the end is inserted inside. With her help, the doctor displays an image on the monitor showing the intestinal cavity from the inside, and can find, for example, tumors. This method can be used to examine all parts of the large intestine.

Diseases

In the vast majority of cases of problems with the intestine, it is a disorder of the stool. Diarrhea, constipation, flatulence - most often the cause of these unpleasant phenomena are the errors in nutrition. In this form, lactose, gluten and some other substances may be intolerant. Dysbacteriosis can also disturb stool disorders or permanent exacerbations of allergies. At the same time, one should not engage in self-medication and take advertised drugs without consulting a doctor, especially if bowel disorders occur on an ongoing basis. This can only exacerbate the problems.

Enough inflammation in any part of the intestine can also be dangerous. If it is not treated, the mucous membrane becomes covered with ulcers, and then rotting processes begin. Even more dangerous is the appearance of formations in the lumen of the intestine. These can be malignant tumors or hemorrhoids, but both require medical attention. Fortunately, almost always the formations are located in the last department, which greatly facilitates access and diagnostics. And, as doctors are inclined to think, almost always bowel diseases, like the whole GASTROINTESTINAL TRACT, are a consequence of malnutrition and lifestyle. Fortunately, modern medicine is capable, if not completely cured, of a person, then to alleviate its condition as much as possible and to preserve the quality of life with minimal interference.

Be healthy!