The jejunum is one of the sections of the small intestine, the length of which is approximately 4-5 meters. The small intestine consists of the duodenum, followed by the lean, and only then - the ileum. The intestine is covered on all sides by a membrane, which is called the peritoneum and is attached to the back wall of the abdomen with the help of the mesentery. The human jejunum is located in the left half of the abdominal cavity. It is projected onto the anterior abdominal wall in the umbilical region, on the sides of the abdomen, and also in the left iliac fossa. The bowel loops are located in horizontal and oblique directions. The length of the jejunum is 2/5 of the total length of the small intestine. Compared to the ileum, the jejunum has thicker walls and a larger diameter of the internal lumen. It also differs in the number of villi and folds that are located in the lumen, the number of vessels, which are larger, but there are fewer lymphoid elements, on the contrary. clearthere are no borders of transition from one section of the intestine to another.
Wall structure
From the outside, the intestine is covered with a special shell throughout. This is the peritoneum, protecting it and smoothing the friction of the intestinal loops against each other. The peritoneum converges at the back of the intestine, and thus the mesentery of the jejunum is formed. It is in it that vessels and nerves pass, as well as lymphatic capillaries that feed the intestine and carry away from it not only the nutrients needed by the body, but also toxic decay products, which then neutralize the liver.
The second layer is smooth muscle tissue, which, in turn, forms two layers of fibers. Longitudinal fibers are located outside, and circular from the inside. Due to their contraction and relaxation, chyme (food that has been exposed to the active substances of the digestive tract in previous sections) passes through the intestinal lumen and gives the body all the beneficial substances. The process of successive contraction and relaxation of the fibers is called peristalsis.
Functionally important layer
The previous two layers provide normal function and protection, but the entire process of food absorption takes place in the last two. Under the muscular layer there is a submucosal layer, it is in it that the lean intestine has blood lymphatic capillaries, accumulations of lymphatic tissue. The mucous layer protrudes into the lumen in the form of folds, due to which the suction surface becomes larger. Additionally, the surface of the mucosa is increased by villi,you can see them only under a microscope, but their role here is very important. They provide a constant supply of nutrients to the body.
Villus
Villi are processes of the mucosa, the diameter of which is only one millimeter. They are covered by a cylindrical epithelium, and in the center there are lymphatic and blood capillaries. Also, the glands that are in the mucosa secrete many active substances, mucus, hormones, enzymes, which contribute to the process of digestion of food. The capillary network simply penetrates the mucosa and passes into the venules, merging, they, together with other vessels, form the portal vein, which carries blood to the liver.
The function of the lean intestine
The main function of the intestine is the processing and absorption of food that has previously been processed by the previous sections of the digestive tract. Food here consists of amino acids that used to be proteins, monosaccharides that used to be carbohydrates, as well as fatty acids and glycerol (what lipids have turned into). The structure of the jejunum provides for the presence of villi, it is thanks to them that all this enters the body and can be used as a nutrient material. Amino acids and monosaccharides enter the liver, where they are further reincarnated and then enter the systemic circulation, fats are absorbed by the lymphatic capillaries, and then enter the lymphatic vessels, and from there they disperse throughout the body with the lymph flow. Everything that is notpassed the test for usefulness in the jejunum, enters the further sections of the intestine, in which the final feces are formed.
From the norm to the disease - one step
The lean intestine has many functions and, in the absence of failures or diseases, functions normally without causing any special problems. But if a failure occurs, then it is time to contact a specialist. Examining the jejunum, like the entire small intestine, is difficult, and tests are important. First of all, it is worth investigating feces, which can tell what kind of failure occurred in the work of the intestines. But a banal inspection and palpation (palpation) will also not be superfluous.
There can be a lot of options for problems in the jejunum, but the main place is occupied by pathology of a surgical, therapeutic and infectious nature. Treatment depends on this, as well as the choice of a specialist who will help get rid of the disease.
With what to go to the surgeon?
It is worth contacting this specialist with diseases, the treatment of which will require surgical intervention. Oncology takes the lead here, malignant and benign processes can be very diverse, and their names depend on what cells the pathologist finds in their composition. Tumor growth can be both in the lumen of the wall and out. When the growth goes into the lumen, bleeding or blockage occurs, which requires immediate surgery.
May also be intestinal obstruction, which is caused by spasms, blockage of the intestinal lumen orintussusception (when one part of the intestine penetrates another). Surgical treatment in this variant of the disease of the jejunum also requires urgent surgical intervention. Obstruction can also be in other parts of the intestine, then a survey radiography of the abdomen becomes important, which will help to correctly establish the diagnosis.
Often there is a pathology such as diverticulitis. This is an inflammation of the jejunum, which is called a diverticulum. Normally, it is absent, and its presence is a congenital pathology. With its inflammation, timely diagnosis is required, which includes complaints of pain, fever, tension in the abdominal muscles. The final diagnosis is made on the operating table and then confirmed by a pathologist.
Other diseases
The jejunum can bring a lot of problems that the surgeon will have to deal with. Sometimes delay in making the correct diagnosis can lead to the death of the patient. What is Crohn's disease worth, which can result in bleeding, abscesses and other complications. Some ailments can lead to dysfunction of the jejunum, and in order to restore them, surgery is also required. So, for example, the adhesive process of the abdominal cavity, especially in places where this section of the small intestine is located, may require surgical excision of adhesions. Operational tactics of treatment are also used for helminthic invasion, when the lumen is clogged with a ball of helminths.
And with what to go to the therapist?
The therapist also has work to do. He, of course, has less work than a surgeon, but she is no less responsible. All diseases and inflammatory changes occurring in the jejunum fall on the shoulders of this specialist. These are colitis, which can be acute and chronic, irritable bowel syndrome and other pathologies. The use of a scalpel for these diseases is not required, but competently and correctly prescribed treatment will help get rid of the disease and restore the joy of life.
Infection does not sleep
It's no secret that the lean intestine contains a huge number of microorganisms in its lumen. Among them there are good and useful for the body, and there are bad ones that are constantly trying to harm. The immune system holds back the onslaught of pathogenic microflora, but sometimes it does not cope with its main task, and then infectious diseases begin. Often there may be unwanted neighbors in the body, helminths strive to get into an excellent habitat, which is the lean intestine for them.
Many diseases can develop in the lumen of the small intestine, such as dysentery, cholera, typhoid fever, salmonellosis and many others. The symptoms they cause vary, but they share a similarity - diarrhea. It can have a different color and smell, be with or without impurities, as well as with blood or water. The final point on the issue of determining the pathogen will be put by a bacteriological study of the released material. Then, based on the sensitivity of the pathogen toantibacterial drugs, appropriate treatment is prescribed. It is also possible to identify helminths, for this it is worth taking feces for analysis, and only an infectious disease specialist will help get rid of them.
