Increase in the amplitude of the s wave in v1 v3. Weak r wave progression what is it. Why is an electrocardiogram performed?

COLON

Functions:

1 suction water and electrolytes from chyme and fecal formation;

2 suction compounds formed as a result of the activity of intestinal microflora: vitamins K and B, products of fiber hydrolysis;

3 mechanical - pushing the contents of the intestine (feces) in the distal direction and removing them from the body;

4 endocrine - due to the presence of DES cells in the intestinal epithelium, which produce hormones that have local and systemic effects;

5 immune - is provided by diffuse lymphoid tissue in the intestinal wall, as well as by special structures - single lymph nodes and their accumulation in the appendix.

Colon comprises four departments: cecum with appendix, colon (ascending, transverse and descending), sigmoid and rectum. Although it is significantly shorter in length than the small intestine, being only about 1.5 m, the duration of passage of undigested food debris through it reaches 90% the total duration of stay of nutrients in the intestine (2-3 days). The colon wall is formed three shells: mucous membrane, muscle And serous

1. Mucosa comprises four layers: epithelium, lamina propria, muscularis lamina and submucosa. Its surface is increased due to constant semilunar folds. There are no villi, intestinal crypts (glands) - deeper than in the small intestine, they are located more often, have a wider lumen and contain cambial elements of the epithelium.

a) epithelium - single-layer prismatic, contains cells four types: (1) prismatic, (2) goblet, (3) undifferentiated (poorly differentiated), (4) endocrine.

(1) prismatic cells - located on the surface of the mucous membrane and in the crypts: tall, narrow, similar to border cells small intestine, however, their brush border is much less developed. They are formed in the depths of the crypt, migrating through which they produce and secrete glycoproteins that accumulate in vesicles in the apical part of the cytoplasm; As they approach the mouth of the crypt, the vesicles disappear, and the microvilli become more numerous and elongate. Provide processes suction.

(2) goblet cells - are located in the crypts and (in smaller numbers) on the surface of the mucous membrane. They are formed in the depths of the crypts from undifferentiated cells, filled with mucous granules. Their number increases in the direction of the rectum. Produce slime, which prevents damage to the mucous membrane and facilitates the movement and removal of feces.

(3) undifferentiated cells - lie deep in the crypts, are cambial elements of the epithelium intestines; As they migrate towards the mouth, the crypts differentiate into goblet-shaped or prismatic cells. Renewal of the epithelium in the large intestine is slower than in the small intestine and takes about 6 days. The desquamation of differentiated cells from the surface of the mucous membrane occurs in the middle between the crypts.

(4) endocrine cells - located in the bottom of the crypts, they belong mainly to EU- andECL-cells(see table).

b) own record - comprises loose fibrous tissue, in which fibroblasts, lymphocytes, eosinophils, macrophages, mast and plasma cells are found. Contains capillaries intertwining crypts and nerve fibers. Reticular fibers look like a dense network. It contains single lymph nodes,(total number more than 20 thousand), which often penetrate through the muscular plate into the submucosa.

c) muscle plate mucous membrane - consists of two layers smooth muscle cells(internal circular and outdoor longitudinal);

d) submucosa - educated loose fibrous connective tissue with a large number of elastic fibers, often contains adipose tissue. It contains lymph nodes(not constant), elements submucosal nervous, venous and lymphatic plexuses.

2. Muscularis - educated two layers smooth muscle tissue: internal circular and external longitudinal. The latter looks like three ribbons, between which the muscle tissue is poorly developed. These ribbons are shorter than the intestine itself, as a result of which it forms multiple pouch-like protrusions - haustra coli. Between the layers of the muscle membrane there are layers connective tissue and elements intermuscular nerve plexus.

3. Serosa - covers some parts of the colon completely, others partially, where it is replaced by adventitia. Forms protrusions in the form of processes containing adipose tissue (appendices epiploicae).

Appendix- a finger-shaped outgrowth of the cecum with a narrow stellate or irregularly shaped lumen, which contains cellular detritus and can become obliterated. The wall of the process is relatively thick due to the high content of lymphoid tissue in it.

1. Mucosa ~ contains the same layers as other parts of the large intestine.

a) epithelium - includes prismatic and goblet cells, and in crypts also poorly differentiated cells, individual Paneth cells and numerous endocrine cells. Locations of lymphatic follicles (domes) covered with epithelium containing M cells.

b) own record contains short crypts, the size and number of which decrease with age, as well as numerous secondary lymph nodes (B-dependent zone) And interfollicular accumulations of lymphoid tissue (T-dependent zone). In the connective tissue there is a large number of diffusely scattered lymphocytes, plasma cells, and eosinophils.

c) muscle plate poorly developed and consists of internal circular and outdoor longitudinal layers smooth muscle cells interrupted in places.

d) submucosa presented loose fibrous connective tissue with a high content of elastic fibers; it partially contains Lymatic nodules.

2. Muscularis formed by internal circular and external longitudinal(solid) layers smooth muscle tissue.

3. Serosa completely covers the vermiform appendix.

The vermiform appendix performs protective function and is, along with Peyer's patch, peripheral organ of the immune system, being part of KALT. It provides absorption of antigenic material from the lumen of the colon, it performance immune-competent cells with development of immune reactions; contains effector B and T cells.

Inflammation of the appendix (appendicitis), which can result in the destruction and rupture of its wall with the subsequent development of inflammation of the peritoneum (peritonitis) - a common disease requiring surgical treatment. It probably occurs due to the activation of the microbial flora located in the lumen of the appendix. An excessively strong (hyperergic) reaction of lymphoid tissue to incoming antigens may play a certain role.

Rectum- distal portion of the colon, ending anal canal. Above the extended bottom (rectal ampulla) there are 2-3 transverse folds of the mucous membrane. The ampoule is dominated by mucous cells; crypts are long.

Anal canal - continuation of the tapering lower part of the ampulla; the mucous membrane forms 5-10 longitudinal folds - anal or rectal speakers (Morgagni), which are connected at the bottom by transverse folds (anal valves). Between the columns there are recesses in the form of pockets - anal sinuses. Crypts in the distal direction shorten and disappear, and single layer prismatic epithelium By dentate (anorectal) line replaced multilayer flat non-keratinizing. Often in the area of epi-body change there is transition zone, containing stratified prismatic or cuboidal epithelium, secreting mucus. The stratified non-keratinizing epithelium is then replaced by keratinizing skin, sebaceous and apocrine sweat glands and hair appear.

Anal glands- rudimentary formations located in submucosa of the anal canal(in some places they penetrate the muscular layer) and open into the anal sinuses.

Intestinal histology is an examination under a microscope of a sample of the mucous membrane of the small or large intestine obtained during endoscopy with biopsy. Using histological examination of tissues, differential diagnosis diseases of the digestive system, determine the prevalence and stage of the process, and choose treatment tactics.

Intestinal diseases have similar symptoms, and a correct diagnosis can only be made after histology. Histology of intestinal tissue reveals:

Preparation for the procedure

Material for histology is obtained during. In order for the study to be as informative and safe as possible, it is important to prepare for it correctly.

Histology of the small intestine

Due to the structural features of the small intestine, only the duodenum, which begins immediately after the stomach, is accessible for biopsy. To obtain a tissue sample of the duodenal zone, it is prescribed. Preparation begins 2 days before the study.

Colon histology

If a tissue biopsy of the rectum and lower part of the sigmoid is necessary, it is prescribed. To examine all parts of the colon, a. Preparation for the study begins 3 days in advance.

Biopsy procedure

Arrive 15-20 minutes before the appointed time, do not forget your passport and medical documentation: referral, medical card or medical history.

Small intestine examination

At the FGDS, take a clean diaper and towel with you. Tell your endoscopist about allergic reactions for medicines.

To reduce discomfort, use a spray with lidocaine, which is sprayed onto the root of the tongue before starting the procedure.
FGDS is performed in the lying position on the left side.
A mouthpiece is inserted into the mouth to prevent the patient from damaging the endoscope with his teeth.
The doctor carefully inserts the endoscope through the oral cavity into the esophagus, then into the stomach and duodenal area. During the procedure, strong salivation and vomiting occur. Try to breathe through your nose, do not swallow saliva.
To straighten the folds and better visualize the image, air is pumped in. In this case, the patient sometimes experiences a feeling of fullness in the stomach.
If pathological changes are detected, the doctor performs a biopsy: he inserts special biopsy forceps through the hole in the endoscope and takes material for examination.
After the biopsy, the doctor removes the forceps and places the pieces of tissue in a jar of alcohol or formaldehyde.
Before removing the equipment, the specialist makes sure that there is no bleeding from the biopsy sites.
The histological material is sent to the laboratory.

The study lasts no more than 5 minutes. FGDS with biopsy is an unpleasant but painless procedure, so only local anesthesia is used.

Colon examination

A clean diaper will be required for colon endoscopy.

Remove clothing below the waist.
Colonoscopy is done in the lying position on the left side, knees brought to the stomach, rectoscopy - in the knee-elbow position.
The doctor lubricates the tip of the endoscope with anesthetic gel and carefully inserts it into the anus. For decreasing discomfort try to relax.
The next stage is to advance the tube along the intestine and examine the walls. Air is pumped in to improve the image.
During the examination, the doctor uses biopsy forceps to pinch off pieces of tissue for histology.
When you feel the urge to defecate, try to breathe deeply.
At the final stage, the doctor makes sure that there is no bleeding and removes the device.

The duration of a rectoscopy is about 15 minutes, a colonoscopy is from 15 to 40 minutes. During the procedure, abdominal pain may occur, sometimes quite intense. They are not associated with a biopsy, but with passing through the bends of the intestine and pumping air. ABOUT pain Tell your doctor right away. At the request of the patient, colonoscopy is sometimes performed under intravenous anesthesia or a sedative is administered in advance.

The endoscopy report is issued immediately after the procedure. Histology analysis requires 5 days. In controversial cases, the drug is examined by several specialists.

Complications

Complications are extremely rare and occur in weakened patients with severe concomitant diseases and pronounced changes in the intestinal wall.

bleeding from the biopsy site;
allergic reaction to medications;
respiratory and cardiac dysfunction during anesthesia.

After FGS, slight sore throat may occur for 1-2 days; after colonoscopy, abdominal discomfort, bloating and diarrhea may occur.

Contraindications

Taking material for histological analysis is serious medical procedure, which has limitations.

In what cases is histology necessary?

The following persons are referred for endoscopy with biopsy: a general practitioner, a gastroenterologist, a proctologist, an oncologist.

Indications:

Do not refuse the proposed examination. Sometimes this is the only way to make a correct diagnosis and prescribe proper treatment.

The stomach is one of the main organs digestive tract. It processes all the products we consume. This is done thanks to hydrochloric acid, which is present in the stomach. Given chemical compound secreted by special cells. The structure of the stomach is represented by several types of tissues. In addition, the cells that secrete hydrochloric acid and other biologically active substances are not located throughout the organ. Therefore, anatomically, the stomach consists of several sections. Each of them differs in functional significance.

Stomach: organ histology

The stomach is a hollow, pouch-shaped organ. In addition to the chemical processing of chyme, it is necessary for the accumulation of food. To understand how digestion occurs, you should know what gastric histology is. This science studies the structure of organs at the tissue level. As you know, living matter consists of many cells. They, in turn, form tissues. The cells of the body differ in their structure. Therefore, the fabrics are also not the same. Each of them performs a specific function. Internal organs consist of several types of fabrics. This ensures their activities.

The stomach is no exception. Histology studies the 4 layers of this organ. The first of these is It is located on the inner surface of the stomach. Next there is the submucosal layer. It is represented by adipose tissue, which contains blood and lymphatic vessels, as well as nerves. The next layer is the muscle layer. Thanks to it, the stomach can contract and relax. The last is the serous membrane. She comes into contact with abdominal cavity. Each of these layers is made up of cells that together form tissue.

Histology of the gastric mucosa

The normal histology of the gastric mucosa is represented by epithelial, glandular and In addition, this membrane contains a muscular plate consisting of smooth muscle. A feature of the mucous layer of the stomach is that there are many pits on its surface. They are located between the glands that secrete various biological substances. Next there is a layer of epithelial tissue. This is followed by the stomach gland. Together with lymphoid tissue, they form their own plate, which is part of the mucous membrane.

Has a certain structure. It is represented by several formations. Among them:

Simple glands. They have a tubular structure.
Branched glands.

The secretory department consists of several exo- and endocrinocytes. The excretory duct of the glands of the mucous membrane exits into the bottom of the fossa located on the surface of the tissue. In addition, cells in this section are also capable of secreting mucus. The spaces between the glands are filled with coarse connective fibrous tissue.

Lymphoid elements may be present in the lamina propria of the mucous membrane. They are located diffusely, but throughout the surface. Next comes the muscle plate. It contains 2 layers of circular fibers and 1 layer of longitudinal fibers. He occupies an intermediate position.

Histological structure of the gastric epithelium

The upper layer of the mucous membrane, which is in contact with food masses, is the epithelium of the stomach. The histology of this section of the gastrointestinal tract differs from the structure of the tissue in the intestine. The epithelium not only protects the surface of the organ from damage, but also has a secretory function. This tissue lines the inside of the stomach cavity. It is located over the entire surface of the mucous membrane. Gastric pits are no exception.

The inner surface of the organ is covered with single-layer prismatic glandular epithelium. The cells of this tissue are secretory. They are called exocrinocytes. Together with the cells excretory ducts glands they produce secretion.

Histology of the fundus of the stomach

The histology of different parts of the stomach is different. Anatomically, the organ is divided into several parts. Among them:

Cardiac department. At this point the esophagus passes into the stomach.
Bottom. In another way, this part is called the fundus department.
The body is represented by the greater and lesser curvature of the stomach.
Antrum. This part is located before the transition of the stomach into the duodenum.
Pyloric section (pylorus). In this part there is a sphincter that connects the stomach to the duodenum. The gatekeeper occupies an intermediate position between these organs.

Big physiological significance has a fundic section of the stomach. The histology of this area is complex. The fundus contains the stomach's own glands. Their number is about 35 million. The depth of the pits between the fundic glands occupies 25% of the mucous membrane. Main function this department- This is the production of hydrochloric acid. Under the influence of this substance, biological activation occurs active substances(pepsin), digestion of food, and also protects the body from bacterial and viral particles. Proprietary (fundic) glands consist of 2 types of cells - exo- and endocrinocytes.

Histology of the submucous membranes of the stomach

As in all organs, under the mucous membrane of the stomach there is a layer of fatty tissue. In its thickness there are vascular (venous and arterial) plexuses. They supply blood to the inner layers of the stomach wall. In particular, the muscular and submucosal membranes. In addition, this layer has a network lymphatic vessels and nerve plexus. The muscular lining of the stomach is represented by three layers of muscle. This is distinctive feature of this body. Longitudinal muscle fibers are located outside and inside. They have an oblique direction. Between them lies a layer of circular muscle fibers. As in the submucosa, there is a nerve plexus and a network of lymphatic vessels. The outside of the stomach is covered with a serous layer. It represents the visceral peritoneum.

and intestines: histology of hemangioma

One of the benign neoplasms is hemangioma. Histology of the stomach and intestines is necessary for this disease. Indeed, despite the fact that the formation is benign, it should be differentiated from cancer. Histologically, hemangioma is represented by vascular tissue. The cells of this tumor are fully differentiated. They are no different from the elements that make up the arteries and veins of the body. Most often, gastric hemangioma forms in the submucosal layer. The typical location for this benign neoplasm is the pyloric region. The tumor can have different sizes.

In addition to the stomach, hemangiomas can be localized in the small and large intestines. These formations rarely make themselves felt. However, diagnosing hemangiomas is important. With large sizes and constant traumatization (chyme, feces) serious complications may occur. The main one is profuse gastrointestinal bleeding. Benign neoplasm difficult to suspect, since in most cases clinical manifestations are missing. An endoscopic examination reveals a dark red or bluish round spot rising above the mucous membrane. In this case, a diagnosis of hemangioma is made. The histology of the stomach and intestines is of decisive importance. In rare cases, hemangioma undergoes malignant transformation.

Gastric regeneration: histology in ulcer healing

One of the indications is gastric ulcer. For this pathology, an endoscopic examination (FEGDS) is performed with a biopsy taken. Histology is required if an ulcer is suspected of malignancy. Depending on the stage of the disease, the tissue obtained may vary. When the ulcer heals, the stomach scar is examined. In this case, histology is needed only if there are symptoms due to which malignant degeneration of the tissue can be suspected. If there is no malignancy, then the analysis reveals cells of coarse connective tissue. When a gastric ulcer becomes malignant, the histological picture may be different. It is characterized by a change cellular composition tissue, the presence of undifferentiated elements.

What is the purpose of gastric histology?

One of the organs of the digestive tract in which neoplasms often develop is the stomach. Histology should be performed if there is any change in the mucous membrane. The following diseases are considered indications for this study:

Atrophic gastritis. This pathology is characterized by depletion of the cellular composition of the mucous membrane, inflammatory phenomena, and decreased secretion of hydrochloric acid.
Rare forms of gastritis. These include lymphocytic, eosinophilic and granulomatous inflammation.
Chronic peptic ulcer of the stomach and duodenum.
Development of “small signs” according to Savitsky. These include general weakness, decreased appetite and performance, weight loss, feeling of abdominal discomfort.
Detection of stomach polyps and other benign neoplasms.
Sudden change clinical picture with long-term peptic ulcer. These include a decrease in intensity pain syndrome, development of aversion to meat food.

The listed pathologies refer to precancerous diseases. This does not mean that the patient has malignant tumor, and its localization is the stomach. Histology helps determine exactly what changes are observed in the tissues of the organ. To prevent the development of malignant degeneration, it is worth conducting research as early as possible and taking action.

Gastric histology results

The results of histological examination may vary. If the organ tissue is not changed, then microscopy reveals normal prismatic single-layer glandular epithelium. When taking a biopsy of deeper layers, you can see smooth muscle fibers and adipocytes. If the patient has a scar from a protracted ulcer, then rough fibrous connective tissue is found. For benign formations, histological results may be different. They depend on the tissue from which the tumor developed (vascular, muscle, lymphoid). The main feature of benign formations is cell maturity.

Sampling of stomach tissue for histology: methodology

To produce histological examination stomach tissue, it is necessary to perform a biopsy of the organ. In most cases, it is performed using endoscopy. The apparatus for performing FEGDS is placed into the lumen of the stomach and several pieces of organ tissue are cut off. It is advisable to take biopsies from several distant sites. In some cases, tissue for histological examination is taken during surgery. After this, thin sections from the biopsy are taken in the laboratory and examined under a microscope.

How long does a histological analysis of stomach tissue take?

If you suspect oncological diseases gastric histology is required. How long does this analysis take? Only the attending physician can answer this question. On average, histology takes about 2 weeks. This applies to planned studies, for example, when removing a polyp.

During surgery, urgent histological examination of the tissue may be necessary. In this case, the analysis takes no more than half an hour.

Which clinics perform histological analysis?

Some patients are interested in: where can gastric histology be done urgently? This study carried out in all clinics with necessary equipment and laboratory. Urgent histology is performed in oncology clinics, some surgical hospitals.

Colon

The colon performs important functions- intense water suction from chyme and the formation of feces. The ability to absorb liquids is used in medical practice to administer nutrients and medicinal substances using enemas. The large intestine produces a significant amount of mucus, which facilitates the movement of contents through the intestines and helps stick together undigested food particles. One of the functions of the large intestine is excretory. A number of substances are released through the mucous membrane of this intestine, for example calcium, magnesium, phosphates, salts of heavy metals, etc. Vitamin K and vitamin B are produced in the colon. This process is carried out with the participation of bacterial flora, which is constantly present in the intestines. With the help of bacteria in the colon, fiber is digested.

Characteristic feature histological structure colon is lack of villi And a large number of goblet cells in the crypt epithelium.

Development. The epithelium of the colon and pelvic rectum develops from the endoderm. In the cutaneous and intermediate zones of the anal part of the rectum, the epithelium is of ectodermal origin. The border between the intestinal and cutaneous epithelium is not clearly defined and is located between the columnar and intermediate zones of the rectum. The epithelium of the intestinal tube grows greatly during the 6-7th week of intrauterine life of the fetus. Villi and crypts in the mucous membrane of the embryo are formed almost simultaneously. Later, mesenchyme grows here, which leads to a strong protrusion of the villi into the intestinal lumen. At the 4th month of embryonic development, the colon anlage contains a large number of villi. Further enhanced growth surface of the mucous membrane leads to stretching and smoothing of these villi. By the end of embryogenesis, there are no longer any villi in the large intestine.

The muscular layer of the colon develops in the 3rd month of the prenatal period, and the muscular plate of the mucous membrane develops in the 4th month of embryonic development.

Colon

The wall of the colon is formed by the mucous membrane, submucosa, muscular and serous membranes.

The relief of the inner surface of the colon is characterized by the presence of a large number circular folds And intestinal crypts(glands), significantly increasing its area. Unlike the small intestine, there are no villi.

Circular folds are formed on the inner surface of the intestine from the mucous membrane and submucosa. They are located transversely and have a semilunar shape (hence the name “semilunar folds”). Intestinal glands (crypts) in colon They are more developed than in thin cells, they are located more often, their sizes are larger (0.4-0.7 mm), they are wider, and contain a lot of goblet exocrinocytes.

Mucous membrane The colon, like the small intestine, has three layers - the epithelium, the lamina propria ( l. propria) and muscle plate ( l. muscularis mucosae).

Epithelium of the mucous membrane single-layer prismatic. It consists of three main types of cells: columnar epithelial cells, goblet exocrinocytes and gastrointestinal endocrinocytes. In addition, there are undifferentiated epithelial cells. Columnar epithelial cells are located on the surface of the mucous membrane and in its crypts. In their structure they are similar to similar cells of the small intestine, but they have a thinner striated border. Goblet exocrinocytes, secreting mucus, are found in large quantities in the crypts. Their structure has been described. At the base of the intestinal crypts lie undifferentiated epithelial cells. They are often visible. Due to these cells, regeneration of columnar epithelial cells and goblet exocrinocytes occurs. Endocrine cells and cells with acidophilic granules are occasionally found.

The lamina propria of the mucous membrane forms thin connective tissue layers between the intestinal crypts. In this plate, single lymphoid nodules are often found, from which lymphocytes migrate into the surrounding connective tissue and penetrate the epithelium.

The muscular plate of the mucous membrane is more pronounced than in the small intestine and consists of two layers. The inner layer is denser, formed mainly by circularly arranged bundles of smooth myocytes. The outer layer is represented by bundles of smooth myocytes, oriented partly longitudinally, partly obliquely relative to the axis of the intestine. The muscle cells in this layer are more loosely located than in the inner layer.

Submucosa contains many fat cells. The vascular and submucosal nerve plexuses are located here. There are always a lot of lymphoid nodules in the submucosa of the colon; they spread here from the lamina propria of the mucous membrane.

Muscularis It is represented by two layers of smooth muscle: internal - circular and external - longitudinal. The outer layer of the muscular layer in the colon has a special structure. This layer is not continuous, and bundles of smooth myocytes in it are collected in three ribbons stretching along the entire colon. In the sections of the intestine lying between the bands, only a thin layer is found, consisting of a small number of longitudinally located bundles of smooth myocytes. These parts of the intestine form swellings (haustra) that bulge outward. Between the two layers of the muscularis propria there is a layer of loose fibrous connective tissue in which the vessels pass and the myenteric nerve plexus is located.

Serosa covers the outside of the colon. Sometimes it has finger-like projections. These outgrowths are accumulations of adipose tissue covered with peritoneum.

Vermiform appendix (appendix)

This organ is characterized by large accumulations lymphoid tissue. The appendix has a triangular lumen in children and a round lumen in adults. Over the years, this lumen can become obliterated, overgrown with connective tissue.

Development. In the development of the human fetal appendix, two main periods can be distinguished. The first period (8-12 weeks) is characterized by the absence of lymphoid nodules, the formation of single-layer prismatic epithelium on the surface and in the crypts, the appearance of endocrinocytes and the beginning of the colonization of the lamina propria of the mucous membrane by lymphocytes. The second period (17-31st week of development) is characterized by intense development of lymphoid tissue and lymph nodules without light centers, the formation of domes under the epithelium located above the nodules. The epithelium covering the dome is single-layer cubic, sometimes flat, infiltrated with lymphocytes. Around the dome area there are high folds of the mucous membrane. At the bottom of the crypts, exocrinocytes with acidophilic granules differentiate. During development, the appendix is populated by both T lymphocytes and B lymphocytes. The completion of the main morphogenetic processes is noted by the 40th week of development, when the number of lymph nodes in the organ reaches 70, the number of endocrinocytes is maximum (EC and S cells predominate among them).

The mucous membrane of the appendix has intestinal glands (crypts) covered with single-layer prismatic epithelium with a relatively small content of goblet cells. At the bottom of the intestinal crypts, Paneth cells (exocrinocytes with acidophilic granules) are found more often than in other parts of the colon. Undifferentiated epithelial cells and endocrine cells are also located here, and there are more of them here than in the crypts of the small intestine (on average, about 5 cells in each).

The lamina propria of the mucous membrane without a sharp boundary (due to the poor development of the muscular lamina mucosa) passes into the submucosa. In the lamina propria and in the submucosa there are numerous large, locally confluent accumulations of lymphoid tissue. When an infection enters the lumen of the appendix, pronounced changes in its wall always occur. Large light centers appear in the lymphoid nodules; lymphocytes strongly infiltrate the connective tissue of the lamina propria, and some of them pass through the epithelium into the lumen of the appendix. In these cases, rejected epithelial cells and accumulations of dead lymphocytes can often be seen in the lumen of the process. Located in the submucosa blood vessels and the submucosal nerve plexus.

The muscular layer has two layers: the inner - circular and the outer - longitudinal. The longitudinal muscular layer of the appendix is continuous, in contrast to the corresponding layer of the colon. On the outside, the process is usually covered with a serous membrane, which forms its own mesentery of the process.

The vermiform appendix performs a protective function; accumulations of lymphoid tissue in it are part of the peripheral sections.

Rectum

Rectal wall ( rectum) consists of the same membranes as the wall of the colon. In the pelvic part of the rectum, its mucous membrane has three transverse folds. The formation of these folds involves the submucosa and the annular layer of the muscular layer. Below these folds there are 8-10 longitudinal folds, between which depressions are visible.

In the anal part of the intestine, three zones are distinguished: columnar, intermediate and cutaneous. In the columnar zone, longitudinal folds form anal columns. In the intermediate zone, these formations unite, forming a zone of the mucous membrane with a smooth surface in the form of a ring about 1 cm wide - the so-called. hemorrhoidal area ( zona haemorrhoidalis).

The rectal mucosa consists of epithelium, lamina propria and muscularis lamina. The epithelium in the upper section of the rectum is single-layer prismatic, in the columnar zone of the lower section it is multilayered, cubic, in the intermediate section it is multilayered squamous non-keratinizing, in the skin it is multilayered squamous keratinizing. The transition from multilayered cubic epithelium to multilayered squamous epithelium occurs sharply in the form of a zigzag - anorectal line (linea anorectalis).

The transition to skin-type epithelium is gradual. Columnar epithelial cells with striated borders, goblet exocrinocytes, and (enterochromaffin-like, or ECL-) cells are found in the rectal epithelium. The latter are especially numerous in the columnar zone. The epithelium in the upper part of the rectum forms intestinal crypts. They are slightly longer than in the colon, but less numerous. In the lower parts of the intestine, the crypts gradually disappear.

The lamina propria of the mucosa takes part in the formation of rectal folds. Single lymphoid nodules and vessels are located here. In the region of the columnar zone in this plate there is a network of thin-walled blood lacunae, the blood from which flows into the hemorrhoidal veins. The lamina propria of this area contains the ducts of the glands located in the submucosa.

In the intermediate zone, the lamina propria contains a large number of elastic fibers, as well as lymphocytes and tissue basophils (mast cells). There are also a few sebaceous glands here.

In the skin area surrounding the anus, to sebaceous glands hair is added. Sweat glands in the lamina propria of the mucous membrane appear at a distance of 1–1.5 cm from the anus; they are tubular glands, the end sections of which are curled into a ring ( gll. circumanales). These are apocrine-type glands, in the secretion of which pheromones are found.

The muscular plate of the mucous membrane, as in other parts of the colon, consists of two layers. The bundles of smooth myocytes gradually turn into narrow longitudinal beams, extending to the columnar zone.

In the submucosa of the rectum there are vascular and nerve plexuses. Sensitive lamellar nerve corpuscles are also found here. In the submucosa lies a plexus of hemorrhoidal veins. When the tone of the walls of these vessels is disturbed, varicose veins. At pathological changes these formations can cause bleeding. In the submucosa of the columnar zone of the rectum there are 6...8 branched tubular formations, stretching to the circular layer of the muscular layer, perforating it and blindly ending in the intermuscular connective tissue. At their ends, ampullary extensions are formed, which are lined with one or two layers of cubic cells. The epithelium of the main ducts of these rudimentary anal glands (gll. anales) consists of several layers of polygonal cells. The mouth of the duct is lined with multilayer flat epithelium. These epithelial tubes are regarded as homologues of the anal glands of animals. In humans, under pathological conditions, they can serve as a site for the formation of fistulas.

The muscular layer of the rectum consists of two layers: the inner - circular and the outer - longitudinal. The circular layer at different levels of the rectum forms two thickenings, which stand out as separate anatomical formations- internal and external sphincters (m. sphincter ani internus et externus). The last muscle, unlike the entire muscular membrane, is formed by striated muscle tissue. The outer longitudinal layer of the muscular lining of the rectum, in contrast to other parts of the large intestine, is continuous. Between both muscle layers there is a layer of loose fibrous unformed connective tissue, in which the muscular-intestinal plexuses and blood vessels lie.

The serous membrane covers the rectum in its upper part; in the lower sections the rectum has a connective tissue membrane.

Innervation. In the parasympathetic musculo-intestinal nerve plexus of the colon, starting from the proximal sections, type I motor neurons are gradually replaced by type II sensory neurons, which become predominant in the rectum.

Afferent innervation in the rectum is pronounced. In the colon, afferent fibers form a sensory plexus in the muscular layer. Sensitive endings look like bushes and terminals ending in smooth muscles.

Some terms from practical medicine:

enterocolitis (enterocolitis; enteritis + colitis) - inflammation of the mucous membrane of the small and large intestine;
anorectal (anorectalis; anat. anus anus + rectum rectum) -- pertaining to anus and rectum;
rectoscopy(recto- + gr. skopeo consider, observe; syn. proctoscopy) - a method of examining the rectum by examining the surface of its mucous membrane using a rectal speculum or rectoscope;
haemorrhoids (haemorrhoides; Greek haimorrhois bleeding, hemorrhoids; syn. varices haemorrhoidales) - a disease caused by dilation of the vessels of the rectal venous plexus; manifested by rectal bleeding, pain in the rectum, etc.;