How do the small and large intestines interact? What are the features of the presented parts of the digestive tract? What role do the small intestines play in the absorption of nutrients? We will try to answer these and other questions in the material presented.
Divisions of the human small intestine
The following sections of the small intestine are distinguished:
- The duodenum connects to the perverse zone of the stomach. This initial section of the small intestine forms a horseshoe-shaped loop around the pancreas. The duodenum is located almost entirely in the retroperitoneal cavity. Only its small process, the ampoule, extends beyond the boundaries of the indicated space.
- The jejunum forms the upper section of the small intestine. It is presented in the form of seven loops that lie on the left side of the peritoneum.
- The ileum is located in the lower right region of the abdominal cavity. Its ending in the form of loops passes into the pelvic area. The ileum connectswith a straight line and is in close proximity to the bladder, uterus (in women).
Physical parameters
The above sections of the small intestine in different areas have an uneven diameter. In the distal zone, the indicator is 2-3 cm, in the proximal zone - 4-6. The thickness of the walls of the small intestine is 2-3 mm, and in the case of tissue contraction it reaches 4-5. The length of the small intestine as a whole can be 5-6 meters. At the same time, her weight in an adult is close to 650 g.
Small intestine: departments, functions
The most important processes of digestion take place in the small intestine. The mucous membrane of local tissues produces a huge amount of active enzymes. They process hummus, a food gruel created by stomach juices. Here, useful elements are absorbed into the lymphatic and blood capillaries, which ensure their transportation to the tissues of organs and systems. Consider what functions the sections of the small intestine perform:
- Duodenum - hydrolysis of proteins, carbohydrates, fats. It provides active production of digestive enzymes. It processes undigested food particles with bile, transports the contents of the stomach.
- The jejunum is a motor, absorptive, hormonal function, hydrolysis of polymers.
- The iliac zone is a transport-motor function. Provides absorption of substances formed as a result of hydrolysis. Recycles bile acids.
The ability of cells in the small intestine to produce hormones
The production of hormones is a special function of local tissues. The sections of the small intestine are not only part of the digestive tract, but also part of the endocrine system. It produces a wide range of hormones that regulate the transport, motor and digestive activity of the intestine.
The following set of endocrine cells is concentrated in the small intestine:
- I-cells – produce cholecystokinin;
- D-cells – somatostatin;
- M-cells – motilin;
- G-cells – gastrin;
- K-cells - insulinotropic glucose-dependent polypeptide;
- S-cells - secretin.
The bulk of hormone-producing cells is located in the jejunum and duodenum. A small part of them is in the iliac.
How does digestion work in the small intestine?
Digestion in the small intestine is performed as follows. The slurry coming from the stomach, pre-treated with saliva and gastric juice, has an acidic reaction. In the small intestine, the presented mass is exposed to alkaline action. This creates optimal conditions for the processing of nutrients by enzymes. The breakdown of the protein components of food gruel occurs under the influence of the following elements of intestinal juices:
- Enzymes enterokinase, kinasogen, trypsin process simple proteins.
- Erepsin breaks down peptides intoamino acids.
- Nuclease breaks down complex molecules of protein origin known as nucleoproteins into trace elements.
- The enzymes m altase, phosphatase, amylase and lactase break down carbohydrates.
- Lipase recycles fats.
After the synthesis of useful substances from food gruel with the help of enzyme processing, carbohydrate and protein components are absorbed by the villi of the small intestine. Further, trace elements enter the venous capillaries in the liver tissue. In turn, the fats are sent to the lymphatic system.
Diseases of the small intestine
The most common ailments that affect the sections of the small intestine are diarrhea and retention of feces in the conductive pathways. Disorders of defecation are often accompanied by the development of pain syndromes in the peritoneum. Quite often, with poisoning and disorders of the small intestine, abundant gas formation is observed. At the same time, the pain is of a short, moderate nature and is not the main factor of discomfort.
A common symptom of the development of malfunctions in the small intestine is rumbling in the peritoneum, a feeling of atypical movement in the abdomen. Most often, such manifestations are the result of abundant gas formation as a result of the consumption of legumes, cabbage, potatoes, rye bread. Significantly increase these symptoms can be at night.
Failures in the production of enzymes and the breakdown of food gruel into trace elements lead to more serious consequences. If aabsorption of food, due to the absorption of substances into the blood and lymphatic vessels, does not occur properly, this can lead to weight loss, weakening of bone and muscle tissue. The consequences of indigestion are often hair loss, dry skin, swelling in the limbs.
There are several basic conditions that lead to the development of pathologies in the small intestine:
- Malabsorption - malabsorption of nutrients.
- Maldigestia - low digestive activity.
If we talk about insufficiently high-quality processing of food gruel, such phenomena occur against the background of a low content of enzymes in intestinal juices. Low fermentation can be either acquired or genetic. Usually, pathologies of this plan are a consequence of chronic inflammation, endocrine diseases, and surgical interventions.
Diagnosis
To diagnose the development of diseases of the small intestine, specialists resort to the following research methods:
- capsule examination;
- USD;
- colonoscopy;
- endoscopy;
- fibroscopy;
- radiography.
As far as tests are concerned, there are standard procedures. The patient gives a stool sample, blood is taken. The stools are examined for the presence of helminths. When studying blood, the speed of movement of red blood cells is taken into account. Additionally, diagnostics are performed, which allows you to evaluate the work of the liver andthyroid.
Treatment
Therapy, aimed at restoring the functions of the small intestine, involves, first of all, the elimination of the underlying disease. With a lack of enzymes in intestinal juices, drugs containing their synthetic substitutes are taken. In case of weight loss, funds for parenteral tissue nutrition are prescribed. The latter contain emulsions of fats, amino acids, protein hydrolysates, concentrated glucose.
If problems are caused by intestinal dysbacteriosis, antibiotics are prescribed. The latter can provoke partial or complete destruction of beneficial flora. For this reason, after therapy, the patient is prescribed to take "Bificol", "Lactobacterin" or "Colibacterin" - biological preparations, which have a positive effect on the restoration of intestinal biocenosis.
Quite often, patients who suffer from disorders in the work of the small intestine are prescribed medications that cause hardening of the feces. These include drugs with a high content of calcium, bismuth. If the formation of liquid stools causes insufficient adhesion of fatty acids, activated charcoal is used to eliminate the problem. All of the above negative manifestations require prior medical attention. To bring the small intestine back to normal, it is important to abandon self-medication, timely diagnose and resort to an adequate, developedtherapy specialist.
In closing
So we have considered what the small intestine is, departments, the structure of the presented part of the digestive tract. As can be seen, local tissues are directly involved in the processing of food, its splitting into individual microelements. The small intestine produces enzymes, vitamins, hormones, substances that enhance the protective functions of the body. At the same time, the occurrence of a deficiency of beneficial bacteria that live on its walls always leads to the development of pathological conditions.
