3.4. SMALL INTESTINE

Small intestine(middle intestine) – has a large length (over 40 m for large and about 30 m for small cattle and horses, over 20 m in pigs) and consists of the duodenum, jejunum, ileum and wall glands associated with the duodenum: liver and pancreas. Diameter small intestine relatively small. The most active processes of digestion and absorption of food occur in the small intestine.

Duodenum – in cattle 90-120 cm long, in small cattle – about 50 cm. Width 5-7 cm in large cattle and 2-3 cm in small cattle. It is suspended on a short mesentery, as a result of which it does not change its position in the abdominal cavity. It is located mainly in the right hypochondrium and only slightly extends into the lumbar region. Starting from the abomasum, it goes forward to the liver. Near the gate of the liver in the right hypochondrium it makes a 5-shaped bend, rises caudodorsally, reaches the right kidney, from here it goes back to the ilium, after which it turns left and forward and passes into the jejunum without sharp boundaries. Approximately in the middle, the bile duct flows into the duodenum, and a little further from it, the pancreatic duct.

The pig's intestine is 40-80 cm long, lies in the right hypochondrium and lumbar region. Heading back, it does not reach the ilium, makes a turn near the right kidney and returns to the liver, where it passes into the jejunum. The bile duct opens at the beginning of the duodenum, and the pancreas opens closer to the middle. In a horse, the intestine is about 1 m long and lies in the right hypochondrium and lumbar region. Its initial section is somewhat expanded. Behind the right kidney, the intestine turns to the left, where it passes into the jejunum. The hepatic and pancreatic ducts flow side by side at a distance of 10-12 cm from the pylorus.

Jejunum - the longest and narrowest intestine. In cattle its length is 37-39 m, in sheep it is about 25 m. It hangs on the mesentery, forming many loops and curls. It is located in the form of a garland around the labyrinth of the colon, mainly in the right half of the abdominal cavity: in the hypochondrium, iliac and inguinal regions.

In a pig, the intestine, 15-20 m long, hangs on a long mesentery, is easily removable, and occupies all the free spaces in the abdominal cavity between the liver and colon. In addition, its loops extend into the xiphoid process, umbilical, iliac and inguinal regions.

The horse's intestine is 20-30 m long and 6-7 cm wide. It hangs on a long mesentery (up to 50 cm), located in a cup-shaped depression formed by the large colon and cecum.

Ileum – short, lies in the right iliac region. In farm animals, its length is about 50 cm. It is suspended on a short mesentery. It starts from the last turn of the jejunum and ends when it flows into the large intestine at the border of the cecum and colon. In the horse it flows into the head of the cecum.

Liver - the largest wall gland in the body, especially in the embryonic period, when it is a hematopoietic organ and occupies most of the abdominal cavity. The functions of the liver are varied. As a digestive gland, it produces bile, which emulsifies fats, saponifies fatty acids, and enhances the action of pancreatic enzymes. The liver performs a barrier function, neutralizing exogenous and endogenous toxins that enter the blood from gastro- intestinal tract, including toxic products of protein metabolism, converting them into urea. In total, the liver performs over 500 functions in the body.

The liver of cattle is massive, brown-red in color, weakly divided into lobes (right and left). It has a convex diaphragmatic surface, adjacent to the diaphragm, and concave - visceral surface, facing the insides. Almost in the center of the visceral surface there is a depression - gate of the liver. In the area of ​​the portal, the liver enters the hepatic artery, portal vein, nerves, exits the hepatic duct and lymphatic vessels. This is also where they are located The lymph nodes. Ventral to the gate lies gallbladder. The cystic duct departs from it, and when it merges with the hepatic duct, it forms bile duct, flowing into the duodenum.

The liver is located in the right hypochondrium, reaching the 2-3rd lumbar vertebra on the right, and the sternum on the left. The liver is attached to the diaphragm, kidney, and duodenum by ligaments. It is connected to the stomach by the lesser omentum.

The pig's liver is relatively larger (up to 2.5%) than that of cattle, and is yellowish in color. Right and left lobe separated from each other by a deep notch. In a horse, the left lobe is divided into left lateral And left medial lobe. The horse has no gallbladder. Bile enters the duodenum through the hepatic duct.

Pancreas– refers to glands with double secretion – external and internal. As an exocrine gland, it produces pancreatic (pancreatic) juice containing trypsin, chemotrypsin, carboxypeptidase, ribonuclease, lipase and other enzymes that break down proteins, fats, and carbohydrates of feed. As an endocrine gland, it produces hormones (insulin, glucagon, lipocaine, which regulate carbohydrate metabolism and are involved in the regulation of protein and fat metabolism. The exocrine part of the gland makes up 97% of its mass and therefore determines its size and shape.

In cattle The gland is yellow-brown in color, has a tuberous surface and consists of a body (middle part), left and right lobes. It is located in the right hypochondrium and in the right part of the lumbar region. At the pig's the right lobe stretches along the duodenum to the right kidney, the left lobe is adjacent to the spleen and left kidney, so that the gland lies in both hypochondriums and extends into the lumbar region. At the horse grayish-pink iron. Lies in both hypochondriums. The body is located in the 5-shaped flexure of the duodenum. The right lobe is weakly separated from the body, the left lobe lies on the lesser curvature of the stomach. The main excretory duct opens into the duodenum along with the hepatic duct.

3.5. LARGE INTESTINE

Colon- consists of the cecum, colon and rectum and ends with the anus - anus. It is where the digestive processes are completed and the formation of feces to be eliminated from the body. Its mucous membrane is devoid of villi. The large intestine in farm animals is on average 4 times shorter than the small intestine. In cattle its length reaches 11 m, in a sheep - 7, in a horse - 9, in a pig - 4 m. It has an unequal diameter throughout. It consists of the cecum, colon and rectum. In the large intestine, absorption occurs mainly of water and salts dissolved in it, as well as the formation of feces.

Cecum – is a blindly ending outgrowth of the initial part of the large intestine. The border between the cecum and colon is the place where the ileum enters the colon, or the cecum. The cecum has strong species differences.

U pigs the cecum is short, thick, cone-shaped; has three tenias and three rows of pockets. Its origin is located near the posterior end of the right kidney, and the apex is directed caudally and curved to the right. U ruminants The cecum is cylindrical, up to 30-70 cm long, smooth-walled, large in diameter, lies in the dorsal third of the right half of the abdominal cavity. Its beginning is at the level of the middle lumbar region, and the apex reaches the entrance to the pelvis. U horses The cecum is highly developed and has the shape of a giant comma. It is distinguished: a base, which has the appearance of a stomach-shaped expansion with greater and lesser curvature, a body and an apex.

Colon - makes up the middle section of the large intestine. Its course in different animal species is extremely diverse. There are ascending and descending limbs on the intestine.

U pigs the loop of the ascending limb of the colon, twisting in a corkscrew fashion, forms cone, which at its base is attached to the lumbar muscles and the right kidney; the apex of the cone lies freely in the umbilical region on the abdominal wall. U ruminants the loop of the ascending limb of the colon twists in a spiral in one plane, forming disk, which is completely located in the dorsal half of the abdominal cavity to the right of the scar. In the colon disc, there is an initial, or proximal, loop, a spiral labyrinth, and a terminal, or distal, loop. U horses colon is very developed and is divided into large and small colons. The first of them corresponds to the ascending limb of the primitive colon, and the second to its descending limb. The large colon is a huge loop consisting of two half-loops connected by the intercolic mesentery.

Rectum represents the relatively short terminal section of the colon. It serves as a continuation of the descending limb of the colon, suspended on the mesentery of the rectum in the pelvic cavity ventral to the sacrum and under the first caudal vertebrae, ending at the posterior meatus (anus). The rectum and anus are attached by muscles and ligaments to the first caudal vertebrae and to the pelvis.

Anal canal is the end of the rectum, adapted for retaining feces. It is formed by a ring-shaped dermal-muscular ridge with an anal or anal opening.

Large intestine: structure, species features, topography.

Colon.

Colon -intestinumcrassum. Consists of the cecum, colon and rectum. Functions: Suction ends there nutrients and water, feces are formed. In herbivores and omnivores, the contents of the colon are retained for a long time, which is necessary for the breakdown of fiber by numerous bacteria and ciliates. In addition, the products of fiber hydrolysis, vitamins K and B, synthesized by microflora, are absorbed here, hormones are produced, characterized by systemic and local effects, and immune protection is provided.

The length of the large intestine in a domestic bull ranges from 6.4 to 11 m; for small livestock (sheep and goats) - from 4 to 7 m; in a domestic pig the average is 4.5 m; for a horse – ranges from 6 to 9 m; in a dog the average is 0.6 m; and in a rabbit it exceeds 2 m.

The wall of all parts of the colon has a similar histological structure. It contains the following layers: mucous membrane, consisting of epithelium, lamina propria and muscularis, submucosa, muscular and serous membranes. Features of the colon– absence of villi of the mucous membrane, weak development of microvilli on epithelial cells, a large number of goblet exocrinocytes.

Mucous membrane The colon is lined with a single-layer prismatic epitheoium, which invaginates into the connective tissue of the lamina propria, forming crypts with wide openings and a lumen. In the integumentary epithelium and crypts there are: prismatic cells, goblet, endocrine and undifferentiated cambial elements. The native layer of the mucous membrane is significantly thickened. In its loose connective tissue there are large numbers of granulocytes, fat and lymphoid cells, as well as blood capillaries and nerve fibers. There are also single and grouped lymph nodes here. The number of crypts changes with age. For example, in a one-day-old calf it is 15 million, and in a ten-year-old cow it increases to 150 million. The muscular plate in the mucous membrane of the large intestine is more pronounced than in the small intestine and is represented by circular and longitudinal layers of smooth muscles. In the connective tissue of the submucosa, elastic fibers and adipose tissue are found in large quantities.

Muscularis The colon is formed by circular and longitudinal layers of smooth muscle. Its longitudinal layer forms cords -teniae, since its length is significantly less than the length of the intestine. Between the cords there is no longitudinal layer of myocytes, but a circular one forms pockets –haustra. In the connective tissue between the muscle layers there are elements of the intermuscular nerve plexus.

Serosa has no pronounced structural features.

Cecum.

Cecum -cecum domestic bull, 30-70 cm long, smooth-walled, cylindrical in shape, large in diameter. It lies in the upper quarter of the right half of the abdominal cavity. The cecum begins from the ileum and colon at the level of the middle of the lumbar region; it is slightly curved and the apex is directed backwards. It distinguishes body -corpusceci And top -apexceci. At the junction of the cecum with the colon, the ileum flows and forms ileocecocolic foramen –ostiumileocecocolicum which is closed sphincter of the ileum -m. sphincterilei. Caecocolic foramen –ostiumcecocolicum has no sphincter.

Peculiarities: In the domestic pig, the cecum is relatively short, but of large diameter. She carries three ribbons - tenii –teniae, three rows pockets –haustra and extends from the middle of the lower back to its end. The body of the intestine lies next to the posterior end of the left kidney, and the apex descends ventrally, backward and to the right.

The horse's cecum is large - 130 cm and has the shape of a giant comma. It distinguishes base –basisceci, body -corpusceci And top -apexceci. The head has a convex greater curvature -curvaturececimajor and concave small curvature -curvaturececiminor. There are two openings on the lesser curvature: the first is the entrance of the ileum into the cecum, and the second is the exit of the colon from the cecum. The entrance and exit openings have sphincters. The base of the cecum is located in the right hypochondrium, right iliac region and in the right half of the lumbar region. The body of the cecum on the right side goes down and forward into the umbilical region; the apex of the cecum is located in the region of the xiphoid cartilage. The cecum has four longitudinal ribbons-tenia - dorsal, ventral, medial and lateral. The lateral and ventral ribbons are absent at the apex; a ligament extends from the dorsal ribbon to the ileum. The remaining tapes are free. The intestinal wall forms four rows of pockets in the spaces between the bands. The cecum is in contact with the lumbar muscles, right kidney, liver, pancreas, duodenum, right and ventral parts of the abdominal wall, with loops of the jejunum and small colon. The body and apex of the cecum are surrounded by the large colon.

In the dog, the cecum forms two or three bends, suspended on a short mesentery between the second and fourth lumbar vertebrae.

Colon.

Colon -intestinumcolon represents the middle section of the large intestine. In the animals studied, it is divided into three sections : ascending colon –colonascendens, transverse colon –colontransversum And descending colon -colondescends. The ascending part of the intestine acquires the greatest development with pronounced species characteristics: in the domestic bull it is located in the form of a spirally twisted disk; in a horse it looks like a double horseshoe, and in a domestic pig it is twisted into a cone. Only in a dog does it have a primitive linear movement.

In the domestic bull, the ascending colon reaches a length of 6-9 m and is divided into three segments: the initial loop, the spiral labyrinth and the terminal loop.

Initial loop -ansaproximaliscoli it is a direct continuation of the cecum; the boundary between them is the inlet of the ileum into the cecum. From it the initial loop goes forward; under the right kidney it turns sharply back and goes over its initial section towards the pelvis, where it turns to left side, making another turn near the cecum. The intestine then moves forward and, at the level of the third lumbar vertebra, enters the spiral labyrinth.

Spiral labyrinth –ansaspiraliscoli is located on the right wall of the scar and in one plane forms convolutions of two orders - centripetal and centrifugal. Centripetal gyri -gyricentripetales the colon, forming 1.5-2.0 turns, go clockwise in the labyrinth. In the center of the disc the intestine makes central bend -flexuracentralis, after which it generates the corresponding number centrifugal revolutions –gyricentrifugals, going counterclockwise. This way it reaches the starting loop and moves into the ending loop.

End loop -ansadistaliscoli smaller diameter than the initial one. It is directed cranially and becomes short transverse colon -colontransversum. Then it goes towards the pelvis in the form descending colon -colondescends, imperceptibly passing into the rectum.

Peculiarities: in the domestic pig, the ascending colon forms a labyrinth in the form of a cone, which with a wide base faces dorsally into the region of the xiphoid cartilage. A centripetal spiral is directed from the wide base of the cone to the center of its apex. It forms the periphery of the cone. The initial loop of intestine is large in diameter and has two teni bands and two rows of pockets. From the center it turns into a centrifugal spiral, following back to the base of the cone and enclosed inside it. The diameter of this part of the loop is smaller. It has no ribbons or pockets. The terminal loop is adjacent to the duodenum, reaches the stomach and the left lobe of the pancreas, turns to the left and passes into the transverse colon.

In a horse, the colon is divided into large - ascending, transverse and small - descending.

Large colon -coloncrassum starts from the cecum, goes forward along the right side of the abdominal cavity and forms ventral right position –colonventraldextrum. Near the diaphragm, the large colon turns from right to left and forms sternal bend -flexurasternalis. Then it is directed along the left side of the abdominal cavity back to the entrance to the pelvic cavity and forms ventral left position –colonventralsinistrum. At the entrance to the pelvic cavity, the large colon turns upward and backward, forming pelvic bend -flexurapelvina. From the bend, the colon follows the path it has already taken. Located above the ventral position, it forms dorsal left position –colondorsalesinistrum, which connects to the left ventral position intercolic mesentery -mesocolon. At the diaphragm, the dorsal portion of the large colon forms diaphragmatic bend -flexuradiaphragmatica and goes into dorsal right position –colondorsaledextrum. The last indicated section of the intestine has the largest diameter and forms ampulla of the colon -ampullacolli. In the caudal direction, its diameter sharply decreases, while the large colon passes into the transverse colon. This section of the intestine is relatively short and quickly passes into small colon -colontenue.

The large colon has four bands and four rows of pouches. There are no ribbons or pockets on her pelvic curve, and the diameter of the intestine here is minimal. In the left dorsal position, the diameter of the intestine gradually increases, three bands and three rows of pouches appear.

The initial part of the large colon is connected to the cecum by the cecum-colic ligament and is attached to the anterior root of the mesentery. The terminal dilated part of the colon is connected by ligaments to the head of the cecum, pancreas, liver, diaphragm and duodenum.

Small colon -colontenue is a continuation of the transverse colon. It has a small diameter, the same throughout the entire intestine, two ribbons and two rows of pockets. The intestine hangs on a long mesentery and forms loops lying in the left iliac region near the entrance to the pelvis. The small colon imperceptibly passes into the rectum.

In the dog, the colon consists of three parts: the right ascending part, running medially from the duodenum forward to the stomach; a short transverse and left descending part, heading back under the left kidney and forming a gentle gyrus in the lumbar region.

Rectum.

Rectum -rectum passes in the pelvic cavity under the spine. In front of the anus, the longitudinal layer of the muscular membrane on the right and left sides forms muscle of the rectum and tail -m. rectococcygeus, which goes up and back to the first caudal vertebrae. The mucous membrane of the rectum and anus is collected in longitudinal folds; it is devoid of villi, but has intestinal glands and many goblet cells, the secretion of which makes the mucous membrane slippery.

Peculiarities: in a domestic pig, the rectum ends with the anus; it is usually surrounded by adipose tissue; there is an ampulla of the rectum. Peyer's patch is quite developed - up to 7 cm. Lymphatic nodules are numerous.

In a horse, the rectum forms an ampulla-shaped expansion. The serous membrane is present only in its anterior part, and at the level of the fourth (fifth) sacral vertebra and caudally, the intestine is already covered from the outside connective tissue. The muscles of the rectum and tail are well developed.

In a dog, the rectum forms an ampulla-shaped expansion. On the side of the anus there are small glandular sacs called paraanal sinuses. They lie between the levator anus and its external sphincter. The secret of steam anal glands Gives dogs a specific smell.

Anal canal.

Anal canal (anus) –canalisanalis (anus) is the end of the rectum, adapted for temporary retention and ejection of feces. The anus protrudes somewhat outward under the tail in the form of an elevation with a central opening. On the surface it is covered with hairless skin containing sebaceous and sweat glands.

The skin of the anus is folded onto its inner surface, forming skin area of ​​the anus -zonecutaneaani. Numerous small holes open here anal glands -gll. circumanales. In this area, a circular layer of smooth muscle forms internal anal sphincter -m. sphincteraniinternus. It is separated from the mucous membrane by a well-developed submucosal layer, and from the external sphincter by a fascial layer. External anal sphincter -m. sphincteraniexternus covers the perimeter of the internal sphincter and is a transversely striated muscle that closes the anal canal. The average thickness of the external sphincter is about 1.5 cm, and the thickness ranges from 0.5 to 1.5 mm.

In the cranial direction, the skin zone of the anus passes into intermediate zone -zoneintermediaani, lined with stratified squamous epithelium and devoid of glands. It is separated from the skin area anal-cutaneous line -lineaanocutanea, and from the mucous membrane of the rectum, lined with marginal epithelium, anorectal line -lineaanorectalis.

In the intermediate zone it stands out in the form of a belt columnar zone –zonecolumnarisani with longitudinal folds separated by sinuses.

Muscle of the rectum and tail -m. rectococcygeus goes from the ventral and lateral walls of the rectum and anus to the first caudal vertebrae. Action: pulls the anus back when excreting feces.

Elevator anus –m. levatorani starts from the ischial spine and pelvic ligament and ends in the wall of the anus. Action: pulls the anus forward after excretion of feces.

Suspensory ligament of the anus -lig. suspensoriumani one end is attached to the second caudal vertebra, the other ends in a loop around the anus. Action: Supports the anus.

Peculiarities: In a domestic pig, the anus is constructed essentially in the same way as in a domestic bull.

In horses, the skin of the anus is rich in sebaceous and sweat glands; the cutaneous-anal and anorectal lines are clearly expressed; submucosal loose connective tissue, suspensory ligament, internal and external sphincters are well developed.

Structure

Small intestine is a narrowed section of the intestinal tube.

Small intestine is very long, representing the main part of the intestine and ranges from 2.1 to 7.3 meters in dogs. Suspended on a long mesentery, the small intestine forms loops that fill most of the abdominal cavity.

Small intestine comes out from the end of the stomach and is divided into three different sections: the duodenum, the jejunum and the ileum. The duodenum accounts for 10% of the total length of the small intestine, while the remaining 90% of the length of the small intestine consists of the jejunum and ileum.

Blood supply

The wall of the thin section is richly vascularized.

Arterial blood comes through the branches abdominal aorta- cranial mesenteric artery, and to the duodenum also via the hepatic artery.

Venous drainage occurs in the cranial mesenteric vein, which is one of the roots portal vein liver.

Lymphatic drainage from the intestinal wall comes from the lymphatic sinuses of the villi and intraorgan vessels through the mesenteric (intestinal) lymph nodes into the intestinal trunk, which flows into the lumbar cistern, then into the thoracic lymphatic duct and the cranial vena cava.

Innervation

The nervous supply of the small part is represented by the branches of the vagus nerve and postganglionic fibers solar plexus from the semilunar ganglion, which form two plexuses in the intestinal wall: intermuscular(Auerbach's) between the layers of the muscle membrane and submucosal(Meissner) in the submucosal layer.

Control of intestinal activity by the nervous system is carried out both through local reflexes and through vagal reflexes involving the submucosal nerve plexus and intermuscular nerve plexus.

Bowel function is regulated by the parasympathetic nervous system, the center of which is its medulla oblongata, from where it extends to the small intestine nervus vagus(10th pair of cranial nerves, respiratory-intestinal nerve). Sympathetic vascular innervation regulates trophic processes in the small intestine.

The processes of local control and coordination of motility and secretion of the intestine and associated glands are of a more complex nature; nerves, paracrine and endocrine chemicals take part in them.

Topography

Intestinal lining

The functional features of the small intestine leave an imprint on its anatomical structure. Highlight mucous membrane And submucosal layer, muscular (external longitudinal and internal transverse muscles) And serous intestinal lining.

Mucous membrane

Mucous membrane forms numerous devices that significantly increase the suction surface.

These devices include circular folds, or Kirkring folds, in the formation of which not only the mucous membrane, but also the submucosal layer, and lint, which give the mucous membrane a velvety appearance. The folds cover 1/3 or 1/2 of the circumference of the intestine. The villi are covered with a special bordered epithelium, which carries out parietal digestion and absorption. The villi, contracting and relaxing, perform rhythmic movements with a frequency of 6 times per minute, due to which they act as a kind of pumps during suction.

In the center of the villus there is a lymphatic sinus, which receives fat processing products. Each villus from the submucosal plexus contains 1-2 arterioles, which break up into capillaries. Arterioles anastomose with each other and during absorption all capillaries function, while during a pause there are short anastomoses. Villi are thread-like outgrowths of the mucous membrane, formed by loose connective tissue rich in smooth myocytes, reticulin fibers and immunocompetent cellular elements, and covered with epithelium.

The length of the villi is 0.95-1.0 mm, their length and density decreases in the caudal direction, that is, in the ileum the size and number of villi are much smaller than in the duodenum and jejunum.

Histological structure

The mucous membrane of the thin section and villi is covered with a single-layer columnar epithelium, which contains three types of cells: columnar epithelial cells with a striated border, goblet exocrinocytes(secrete mucus) and gastrointestinal endocrinocytes.

The mucous membrane of the thin section is replete with numerous parietal glands - the common intestinal, or Lieberkühn's glands (Lieberkühn's crypts), which open into the lumen between the villi. The number of glands averages about 150 million (in the duodenum and jejunum there are 10 thousand glands per square centimeter of surface, and 8 thousand in the ileum).

The crypts are lined with five types of cells: epithelial cells with a striated border, goblet glandulocytes, gastrointestinal endocrinocytes, small borderless cells of the crypt bottom (stem cells intestinal epithelium) and enterocytes with acidophilic granules (Paneth cells). The latter secrete an enzyme involved in the breakdown of peptides and lysozyme.

Lymphoid formations

For duodenum characteristic tubular-alveolar duodenal, or Bruner's glands, which open into crypts. These glands are a continuation of the pyloric glands of the stomach and are located only on the first 1.5-2 cm of the duodenum.

The final segment of the thin section ( ileum) is rich in lymphoid elements, which lie in the mucous membrane at different depths on the side opposite to the attachment of the mesentery, and are represented by both single (solitary) follicles and their clusters in the form of Peyer's patches.

Plaques begin in the final part of the duodenum.

The total number of plaques is from 11 to 25, they are round or oval shape length from 7 to 85 mm, and width from 4 to 15 mm.
The lymphoid apparatus takes part in the digestive processes.

As a result of the constant migration of lymphocytes into the intestinal lumen and their destruction, interleukins are released, which have a selective effect on the intestinal microflora, regulating its composition and distribution between the thin and thick sections. In young organisms, the lymphoid apparatus is well developed, and the plaques are large.

With age, a gradual reduction of lymphoid elements occurs, which is expressed in a decrease in the number and size of lymphatic structures.

Muscularis

Muscularis represented by two layers of smooth muscle tissue: longitudinal And circular, and the circular layer is better developed than the longitudinal one.

The muscularis propria provides peristaltic movements, pendulum movements, and rhythmic segmentation that propel and mix the intestinal contents.

Serosa

Serosa- visceral peritoneum - forms the mesentery, on which the entire thin section is suspended. At the same time, the mesentery of the jejunum and ileum is better expressed, and therefore they are combined under the name mesenteric colon.

Functions

Digestion of food is completed in the small intestine under the action of enzymes produced by the wall ( liver And pancreas) and wall ( Lieberkühn and Brunner) glands, absorption of digested products into the blood and lymph, and biological disinfection of incoming substances.

The latter occurs due to the presence of numerous lymphoid elements enclosed in the wall of the intestinal tube.

The endocrine function of the thin section is also great, which consists in the production of some biologically active substances by intestinal endocrinocytes (secretin, serotonin, motilin, gastrin, pancreozymin-cholecystokinin, etc.).

It is customary to distinguish three sections of the thin section:

• initial segment, or duodenum,
• middle segment, or jejunum,
• and the final segment, or ileum.

Duodenum

Structure

The duodenum is the initial section of the thin section, which is connected to the pancreas and the common bile duct and has the form of a loop facing caudally and located under lumbar region spine.

The length of the intestine is on average 30 cm or 7.5% of the length of the thin section. This section of the thin section is characterized by the presence of duodenal (Bruner's) glands and a short mesentery, as a result of which the intestine does not form loops, but forms four pronounced convolutions.

Topography

The cranial part of the intestine forms S-shaped, or sigmoid gyrus, which is located in the pylorus region, receives the ducts of the liver and pancreas and rises dorsally along the visceral surface of the liver.

Under the right kidney, the intestine makes a caudal turn - this cranial gyrus of the duodenum, and goes to descending part, which is located in the right iliac.

This part passes to the right of the root of the mesentery and under the 5-6 lumbar vertebrae passes to the left side transverse part, dividing the mesentery into two roots in this place, and forms caudal gyrus of the duodenum.

The intestine is then directed cranial to the left of the mesenteric root as ascending part. Before reaching the liver, it forms duodejejunal gyrus and passes into the jejunum. Thus, a narrow loop of the anterior root of the mesentery is formed under the spine, containing the right lobe of the pancreas.

Jejunum

Structure

The jejunum is the longest part of the small section and is about 3 meters, or 75% of the length of the small section.

The intestine got its name due to the fact that it has a half-dormant appearance, that is, it does not contain voluminous contents. It is larger in diameter than the ileum located behind it and is distinguished by a large number of vessels passing through a well-developed mesentery.

Due to its considerable length, developed folds, numerous villi and crypts, the jejunum has the largest absorption surface, which is 4-5 times greater than the surface of the intestinal canal itself.

Topography

The intestine forms 6-8 skeins, which are located in the region of the xiphoid cartilage, umbilical region, ventral part of both ilia and groins.

Ileum

Structure

The ileum is the final part of the thin section, reaching a length of about 70 cm, or 17.5% of the length of the thin section. Externally, the intestine is no different from the jejunum. This section is characterized by the presence of a large number of lymphoid elements in the wall. The final section of the intestine has thicker walls and the highest concentration of Peyer's patches. This section runs straight under the 1st-2nd lumbar vertebrae from left to right and in the area of ​​the right ilium flows into the cecum, connecting with it by a ligament. At the point where the ileum enters the cecum, the narrowed and thickened part of the ileum forms ileo-cecal valve, or ileal papilla, which has the appearance of a relief ring-shaped damper.

Topography

This section of the small intestine received its name due to its topographic proximity to the iliac bones, to which it is adjacent.

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Purpose of the lesson: To study the composition, function, structure and specific features of the small intestine. Study the classification of digestive glands, their topography, structure and species characteristics. Material support: the corpse of a dog with an open abdominal cavity, the small intestines of domestic animals, tables, museum preparations.

Middle or small intestine – intestinum tenue

From the pylorus of the stomach to the cecum. According to its position, it is divided into the duodenum, jejunum and ileum.

The mucous membrane is glandular, columnar epithelium.

Villi – velli intestinales.

Unicellular - mucous.

Multicellular - tubular.

A. Intestinal glands – glandula intestinales.

B. Duodenal glands – glandula duodenales.

Lymph nodes:

Single lymph nodes - limphonoduli solitarii.

Lymphatic (Peyer's) patches (aggregate lymph nodes) – limphonoduli aggregate.

Muscular membrane: outer - longitudinal, inner - circular smooth muscle tissue.

The serous membrane is mesothelium, a single-layer squamous epithelium.

Passes into the mesentery - mesentericum.

· Duodenum – duodenum

The duodenum is located in all domestic animals in the right hypochondrium and extends its portion into the renal region. The duodenum is suspended on a short mesentery and therefore has a constant position. Coming out of the pyloric part of the stomach, it goes back to the right kidney, its initial site. It lies on the liver, forming an S-shaped bend here.

Species features of the duodenum:

Dog, pig, horse. The duodenum goes around the right kidney, goes forward and passes into the jejunum.

Cattle. It reaches the wing of the ilium, forming a loop here, and then goes down and forward and passes into the jejunum. Between the layers of the mesentery lies the pancreas. In the duodenum, intensive digestion of food occurs due to the presence of a large number of parietal and two wall glands.

The major nipple of the duodenum is papilla duodeni major.

Lesser duodenal nipple – papilla duodeni minor.

· Jejunum - jejunum

The jejunum at autopsy is always empty; it is suspended on a long mesentery, therefore it forms a large number of intestinal loops - ansae intestinales. The final section of the jejunum has a shortened mesentery and the intestine passes without borders into the ileum.

Species features of the jejunum:

Dog. The jejunum lies in the ventral part of the ileum and umbilical regions.

Pig. Lies ventrally between the colon and stomach, the umbilical region and the region of the xiphoid cartilage.

Cattle. Lies ventrally in the right ilium.

Horse. Located in the lumbar region and left iliac region.

Ileum - ilium

The short ileum lies in the left iliac region and flows into the cecum.

The cecal iliac ligament is plica ileocecales.

Sphincter of the ileum - m. sphincter ilei.

Nipple – papilla ilealis.

The opening is ostium ilealis.

The frenulum of the nipple is frenulum papillae ilealis.

Types of features of the ileum:

Dog. The ileum flows through the nipple into the large intestine at the border of the cecum and colon, at the level of the 1st-2nd lumbar vertebrae.

Pig. The ileum enters in a sleeve-like manner into the large intestine, between the cecum and colon.

Cattle. The ileum is located between the cecum and colon, enters the large intestine from the back and to the right at the level of the 4th lumbar vertebra.

Horse. The ileum is located in the right ileum. It is directed from left to right towards the lesser curvature of the cecum, i.e. dorso-caudally.

Intestine (intestinum) - department digestive tract, in which successive stages of feed digestion, nutrient absorption and feces formation occur.

Clinical study intestines is carried out by inspection and palpation of the abdominal wall. In large animals, rectal palpation, percussion, auscultation, fecal examination are performed, rectoscopy, intestinal puncture, and laparoscopy are also used; in small animals - fluoroscopy. Significant value have anamnesis data and clinical picture.

Inspection establish changes in the shape of the abdomen, posture, the appearance of anxiety, features of defecation, physical and chemical properties of feces.

In case of intestinal diseases, an increase in abdominal volume (flatulence) is noted; decrease in volume due to peritonitis and intestinal emptying, for example due to diarrhea; anxiety with pain. Spasmodic pain (with enteralgia) is paroxysmal. They manifest themselves in the form of repeated attacks. Distension pain that occurs as a result of stretching of the intestines (stomach) is long-lasting and dulls gradually. Pain due to tension of the mesentery during false displacements, rotations and intestinal strangulation is constant and intensifies when the tension of the mesentery is weakened. Animals take peculiar poses; bend the spine, stand with limbs tucked under the stomach, etc. Peritoneal pain is constant, intensifying with movement and squeezing the abdomen. The abdominal walls are tense, the stomach is tucked. Pain observed during defecation is characteristic of pathological processes in the rectum (tenesmus).

Palpation First, a superficial one is carried out through the abdominal wall, and then a penetrating and deep one. Superficial palpation determine the tension and sensitivity of the abdominal wall, penetrating deep - location, shape, mobility, intestinal soreness and the nature of the contents (in small animals); In large animals, rectal examination is used for this purpose.

Percussion carried out taking into account the topography of various parts of the intestine. Usually they start from the hungry hole and gradually move down. In healthy animals, when percussing the abdominal wall in the areas of intestinal projection, tympanic or dull sounds of various shades are detected. With coprostasis and intussusception, percussion produces a dull sound if there are no parts of the gastrointestinal tract filled with gases between the affected intestine and the abdominal wall. When the intestines are distended, percussion reveals a loud tympanic sound, and later, when the intestinal wall and abdomen are tense, an atympanic sound is detected.

Auscultation allows you to study intestinal motility. Noises in the small intestine resemble the sound of overflowing liquid; gurgling in the large intestine is heard in the form of rumbling, they are more dull, giving the impression of sounds coming from afar. The frequency and intensity of bowel sounds depend on peristalsis, filling with gases and contents. These noises can be loud or weak, long or short, constant or temporary, frequent or infrequent. With enteritis, there may be their intensification, weakening, absence or appearance of noise with a metallic tint. Strengthening is noted when liquid consistency contents, large amounts of gases, inflammation, in the initial stages of flatulence and obstruction. Peristaltic noises take on a metallic tint when a large amount of gas accumulates. Intestinal flatulence (especially the cecum in horses) is characterized by a phenomenon called the “drop sound”, which is created by drops of intestinal juice falling from above onto the liquid-filled bottom of the intestine.

When peristalsis weakens, the noises become rare, short-lived, weak, and sometimes can only be heard occasionally. The weakening of noise is characteristic of intestinal atony, which develops as a result of severe inflammation of the intestinal wall and prolonged flatulence.

The disappearance of intestinal sounds is observed with paralysis of the intestinal muscles in patients with peritonitis, flatulence, intestinal obstruction, which entails distal paralysis and proximal flatulence.

Test puncture of the abdominal wall carried out to obtain punctate from the abdominal cavity, the examination of which is necessary for the diagnosis of peritonitis, ascites, rupture of the stomach and intestines.

Rectoscopy makes it possible to establish inflammation, ruptures, ulcers, neoplasms and other changes in the rectal mucosa.

Study of the intestines of ruminants. The small and large intestines of ruminants are located in the right half of the abdominal cavity (Fig. 45).

Slight tension in the abdominal wall in calves, sheep and goats facilitates examination, especially by external palpation, which can be used to diagnose intussusception, flatulence, and intestinal inflammation. With intussusception and inflammation of the small intestine, pain is observed in the lower right part of the abdomen; with peritonitis, a diffuse pain reaction is noted.

Rice. 45. Position internal organs cows (right view):

/ - rectum; 2- abdominal aorta; 3 - left kidney; 4- right kidney; 5- liver (turned away); b - gallbladder; 7-diaphragm dome circuit; 8- right lung; 9 - esophagus; 10 - trachea; 11 - heart; 12- contour of the diaphragm attachment along the ribs; 13- abomasum; 14- duodenum; /5 - pancreas; 16- jejunum; 17- colon; 18- end of the ileum; 19- cecum; 20 - bladder; 21 - vagina

Percussion start from the hungry hole, moving gradually downwards (Fig. 46). The percussion field of the duodenum is located under the transverse processes of the lumbar vertebrae (behind the hepatic and renal dullness) for 5-6 cm. A loud tympanic sound is heard here. The field of percussion of the cecum is located in front and below the external iliac angle. The percussion sound is loud and tympanic. The percussion field of the colon is located under the duodenum and behind liver dullness. Below it, behind the book, abomasum and hepatic dullness, there is a percussion field of the jejunum. The percussion sound in the upper part of the intestinal tract is dull-tympanic, gradually turning downward into a quiet, short, dull sound.

Limited dullness (dullness) is possible with intussusception and blockage of individual segments; a loud tympanic or atympanic sound occurs when bloated with gases.

At auscultation sounds of the small and large intestines are heard on the right abdominal wall. They are short and rare, reminiscent of the sounds of gurgling. The sounds of the small and large intestines in ruminants are little distinguishable: the sounds of the large intestine are duller and rougher than those of the small intestine, sometimes heard in the form of periodic gurgling.

Increased noise is a sign of peristalsis, the appearance of gases and liquid contents. Especially loud noises listen when fermentation intensifies, they acquire a ringing hue. With atony and intestinal obstruction, the noise weakens or disappears.

During a rectal examination, it is necessary to verify the normal topographic relationships and condition of the organs. In the case of a pathology that changes morphological structure and topographic relationships of the abdominal organs or the function that distorts them, one can get an idea of ​​the localization, nature and character of this pathology.

During rectal examination The rumen and intestines determine their size, shape, position, degree of filling, properties of the contents, sensitivity, and peristalsis. First, the tension of the anal sphincters and the filling of the rectum, the properties of its contents, the condition of the mucous membrane, the strength of peristaltic waves are determined, then the bladder, uterus, and pelvic bones are palpated.

When you insert your hand into the rectum, tension in the sphincters of the anus is felt; it is stronger in young animals and weaker in old, emaciated animals.

In the case of a pathological condition, the sphincter tone may be increased or decreased. A painful increase in sphincter tone is characteristic of obstruction and tetanus. Weakening is observed when prolonged diarrhea, exhaustion, spinal paralysis and forced lying down. The highest stage of the disorder is gaping of the anus due to sacral paralysis.

Rice. 46. ​​Percussion field abdominal organs in cattle (right view):

1 - rectum; 2- cecum; 3 - colon; 4- right kidney; 5- liver; 6- book; 7-rennet; 8 - jejunum; 9 - ileum; M- maklok line; P - line of the scapulohumeral joint (designations for the nature of the percussion sound are the same as in Fig. 44)

If there is severe straining, you should stop inserting your hand into the rectum and wait until the resistance stops. If intestinal spasms recur periodically, the arm is inserted in the intervals between spasms. With paralysis of the rectum, the tone of its walls disappears.

Normally, the rectum is moderately filled with feces, its mucous membrane throughout is smooth, moist-slippery and warm.

During painful defecation, especially with peritonitis, spinal paralysis, a lot of feces accumulate in the rectum, it fills almost the entire pelvic area and puts pressure on neighboring organs. The absence of feces in the rectum indicates a cessation of movement of contents due to intestinal obstruction. In case of proctitis and mechanical obstruction, a large amount of mucus is found in the rectal cavity; in cases of fibrinous and diphtheritic enterocolitis, a film or thread of fibrin is found. With wounds and swelling, the rectal mucosa is infiltrated, swollen, folded.

In some cases, blood gives the stool a characteristic coloring, in others it flows freely from the anus. An admixture of blood is found in intussusception, volvulus, hemorrhagic inflammation, and coccidiosis. Bleeding is a sign of injury posterior section intestines.

Deep research in the left half of the abdominal cavity a scar is found, the dorsal sac of which is filled with gases, and the underlying part with feed masses of a dough-like consistency. In the right half of the abdominal cavity, in the upper part, the large intestines are palpable in the form of a disk, and caudally and below - the small intestines.

Among the changes important have general and local flatulence, displacements, adhesions of loops with neighboring organs, intestinal blockage, coprostasis, the presence of fluid in the abdominal cavity, rumen overflow, displacement of the abomasum.

General and local possible intestinal flatulence. General flatulence sometimes develops with peritonitis, intestinal inflammation, rumen tympania, and local flatulence sometimes develops with strangulation, intussusception, or intestinal infarction.

Bowel displacements depending on the state of its lumen, they can be false and true. False displacements are movements of loops that, with an increase in volume, move in one direction or another (with flatulence), while intestinal patency is maintained. True displacements are associated with impaired patency and are extremely life-threatening. In ruminants, pinching of individual loops, strangulation, blockage, and twisting of individual loops are more common.

Hernias There are umbilical, abdominal, scrotal, femoral, inguinal, diaphragmatic, as well as internal spermatic in bulls, intestinal ligaments.

When the localization of the infringement is inaccessible to palpation, the justification for intestinal obstruction is local, pronounced flatulence, cessation of filling of the rectum with feces, accumulation of mucus in its lumen and increased tone of the anal sphincter. Intussusception without obstruction of patency, it is characterized by the fact that in the right half of the abdominal cavity an oblong cylindrical body or a package of painful intestines with a pasty consistency is probed, and if patency is obstructed, local flatulence occurs.

When the phyto- And Miloconcretions Rectal examination in the right half of the abdominal cavity sometimes reveals a dense body, part of the intestine stretched by the contents above and collapsed below the obstruction, increased pain sensitivity of the intestine at the site of blockage. When stool of dense consistency stagnates, palpation can reveal a loop with dense contents, in which a dent remains under pressure.

Rectoscopy allows you to examine the intestinal mucosa, conduct a targeted biopsy followed by morphological examination.

Examination of the horse's intestines. The same methods are used as in cattle, but taking into account the topographical features of the intestinal location (Fig. 47 and 48).

Rice. 47. Position of the horse's internal organs (left view):

1 - trachea; 2-esophagus; 3 - diaphragm; 4 - liver; 5-stomach; 6-spleen; 7-left kidney; 8- small colon; 9 - left ovary; 10 - left oviduct; 11 - wide uterine ligament; 12 - left horn of the uterus; 13 - vagina; 14- rectum; /5 - genitourinary vestibule; 16- genital slit; 17- anal (anal) opening; 18- bladder; 19- pelvic loop of the large colon (transition of the lower to the upper knee); 20- left lower (ventral) knee of the large colon; 21 - left upper (dorsal) knee of the large colon; 22 - jejunum (circumcised); 23- transverse (diaphragmatic) lower (ventral) knee of the large colon; 24- transverse (diaphragmatic) upper (dorsal) knee of the large colon; 25-heart; 26- pulmonary artery; 27-thoracic aorta; 28- common brachiocephalic trunk

Rice. 48. Position of the horse’s internal organs (right view):

1 - rectum; 2 - pelvic flexure of the large colon; 3- cecum; 4- duodenum; 5- right kidney; 6- liver; 7- diaphragm; 8- esophagus; 9- thoracic aorta; 10- right azygos vein; 11 - trachea; 12- anterior vena cava; 13- heart; 14 - posterior vena cava; /5 - right upper longitudinal knee of the large colon; 16- right lower longitudinal knee of the large colon; 17- jejunal loops; 18- bladder; 19- end of the seed tube; 20 - prostate; 21- right vesicular gland

Inspection. The part of the small intestine accessible for external examination is located mainly in the left half of the abdominal cavity, and the large intestine - in the right and partially in the lower part of the left half of the abdominal cavity. An increase in the volume of the abdomen during flatulence occurs due to the accumulation of gases in the large intestine, so the protrusion is installed in the right iliac region. The accumulation of gas in the small intestine is not accompanied by a significant increase in the abdomen. A decrease in the abdomen is noted with prolonged diarrhea, malnutrition and peritonitis.

Percussion. The percussion sound depends on the degree of filling of the intestine, the nature of the contents and the degree of its adherence to the abdominal wall. Percussion of the jejunum is carried out on the left in the middle third of the abdomen, in the area of ​​the iliac and the left hungry fossa, while in healthy animals a dull-tympanic or dull sound is heard (Fig. 49). In the lower third of the abdomen, the left ventral and dorsal knees of the large colon are percussed, and in the upper third, above the small intestine, the small colon is percussed. The percussion sound above them ranges from dull to tympanic. The percussion field of the cecum is on the right, in the area of ​​the hungry fossa and the superior iliac region. Cranial from it and down the hypochondrium there is a percussion field of the right ventral and dorsal knees of the large colon, and caudally in a narrow strip there is a percussion field of the small intestine. The percussion sound above the head of the cecum is usually loud, approaching tympanic (Fig. 50).

When percussing parts of the intestine filled with gases, if they are adjacent to the abdominal wall, a loud tympanic or atympanic sound is detected, and with coprostasis - a dull sound.

Rectal examination. First, the tension of the anal sphincters, the filling of the rectum, the condition of its wall and mucous membrane are determined. Then the small colon is examined, the loops of which are located under the last lumbar and first sacral vertebrae. They are mobile and contain fecal skibals located at some distance from each other. At the top and middle parts of the left half of the abdominal cavity, in the recess formed by the cecum and large colon, the small intestines are examined, which are well palpated with an increase in volume and increased pain. In the left iliac region, below a horizontal line drawn from the pubic bone, the left ventral and dorsal positions of the large colon are examined. In this case, the pelvic bend is determined by the arcuate curvature, and the ventral position is determined by the longitudinal shadows and pockets. Normally, the consistency of the intestine is doughy. In the right half of the abdominal cavity, the cecum is palpated, which occupies the area of ​​the right

Rice. 49. Percussion field of the abdominal organs in a horse (left view):

1 - stomach; 2-left kidney; 3 - spleen; 4- colon; 5- jejunum; M- maklok line; /7-line of the scapulohumeral joint; a - loud tympanic sound; b- dull tympanic sound; V - dull sound; g - dull sound

Rice. 50. Percussion field of the abdominal organs in a horse (right view):

1 - jejunum; 2 - right kidney; 3 - colon; 4 - cecum; M- mak-lok line; P - line of the scapulohumeral joint (designations for the nature of the percussion sound are the same as in Fig. 49)

sigh. It has a large diameter, the shadows run along back wall from top to bottom and forward, the pockets are located one below the other, the head is filled with gases, and the contents have a doughy consistency. To the left and in front of the cecum, a stomach-shaped expansion of the large colon is examined in the form of a semicircular body with a smooth surface.

You can also palpate the spleen, left kidney, bladder, uterus, vagina, posterior part of the aorta and its individual terminal branches, part of the surface of the peritoneum, inguinal rings in males, located at the bottom of the hypogastrium. The epigastrium and lower part of the mesogastrium are not palpable.

Rectal examination is the most valuable method for diagnosing colic. Increased tone of the anal sphincters, cessation of filling of the rectum, dry mucous membrane, an abundance of thick mucus in the rectum are signs of blockage, volvulus, intestinal torsion and other forms of obstruction, and the presence of blood in the stool is thromboembolic colic, intussusception.

In case of acute dilatation of the stomach, it is possible to palpate rectally the spleen shifted caudally, behind the last rib, and in small horses, the stomach in the form of a rounded body with a tense wall. With intestinal flatulence, the intestines are evenly swollen with gases. Detection of local flatulence during prolonged colic suggests the presence of mechanical ileus.

With chymostasis of the duodenum, a bend stretched by compacted contents is detected behind the anterior root of the mesentery. In the case of chemostasis of the ileum, by moving the hand from bottom to top and from left to right to the head of the cecum in the right half of the abdominal cavity, the posterior loop of the ileum is palpated in the form of a cylindrical body of doughy or dense consistency, often painful, as it approaches the cecum, less mobile. With coprostasis of the cecum, gastric dilatation and pelvic flexure of the large or small colon, it is possible to palpate areas filled with a mass of dense consistency; the intestinal wall may be painful.

An accurate diagnosis of volvulus, torsion, intussusception, internal strangulation and obstruction of the intestines can be made only if the location of the obstruction is determined rectally.

Study of the intestines in pigs. In the pig, the duodenum is located in the right hypochondrium dorsocaudal to the right kidney, where it turns to the left and is directed cranially next to its initial section. Then it returns to the stomach and passes into the jejunum, which forms a group of loops between the stomach and liver, on the one hand, and the conus of the colon, on the other, occupying mainly the right half of the abdominal cavity. The ileum passes into the colon dorsocranially and to the right, between the cecum and colon. The cecum is short, cone-shaped, its anterior end is located near the posterior end of the right kidney, and the apex is directed caudally and curved to the right. The colon is folded in the form of a cone, which with a wide base is located dorsally in the lumbar region and left iliac region, and the apex lies in the pubic region. The large intestines occupy predominantly the left half of the abdominal cavity.

In pigs, the small intestines are examined by inspection, palpation, percussion and auscultation, mainly with right side and the lower third of the abdomen on the left side; thick - mainly on the left side (Fig. 51). With flatulence, protrusion of the abdominal walls can be noted; An increase in the left side indicates flatulence of the large intestine, and an increase in the right side indicates flatulence in the small intestine.

With external deep palpation In piglets and lean pigs, coprostasis, lumpy packets of immobile intestinal loops can be found in chronic tuberculosis and plague. In well-fed pigs, external examination is ineffective.

Rectal examination carried out with a finger. The properties of the contents of the rectum and the condition of its mucous membrane are determined. You can use rectoscopy and fluoroscopy.

Rice. 51. Position of the pig’s internal organs (left view):

1 - esophagus; 2- trachea; 3 - left lung; 4 - stomach; 5-spleen; 6- left kidney; 7-colon; 8-cecum; 9 - left horn of the uterus; 10- left ureter (cut); 11 - bladder; 12 - rectum; 13 - jejunum; 14- liver; 15- heart

Study of the intestine in carnivores. They have a thin and large intestine There is almost no difference in diameter. Duodenum from stomach goes in the right hypochondrium and right ilium, then turns to the left, goes around the cecum and goes medial to the left kidney towards the stomach, where it passes into the jejunum, which forms many loops. The ileum flows into the large intestine at the border of the cecum and colon, at the level of the 1st-2nd lumbar vertebrae. The cecum forms 2-3 bends, suspended on a short mesentery in the region of the 2-4th lumbar vertebrae to the right of the median plane. The colon from the confluence of the ileum is directed first cranially as an ascending (right) knee, and then from the right kidney it turns to the left, forming a short transverse knee. Behind the left kidney, the intestine bends caudally and, like the descending (left) knee, goes into the pelvic cavity, where it passes into the rectum.

Loops small intestines examined on the left side in the lower part of the abdominal wall (Fig. 52), and the colon and rectum in its upper part. On the right side, in the lower part of the abdominal wall, the loops of the small intestines are examined anteriorly, in the middle part - the duodenum, in the upper part of the groin - the cecum, which is in contact with the abdominal wall, and in the back part of the groin at the top - the descending part and the rectum (Fig. 53 ).

Palpation, especially deep bimanual, it is possible to determine the tension of the abdominal wall, sensitivity, location, shape, mobility, pain in the intestine, its

Rice. 52. Chest and abdominal cavity dogs (left side):

1-13 - ribs; a, a", a" - left lung; b - pericardium; in - diaphragm; g - liver; d - stomach; e - spleen; and - left kidney; h - left ovary; and - colon; To - loops of small intestines; l - bladder

filling and consistency of the contents. This method has great importance for the diagnosis of coprostasis, intussusception, tumors, detection of foreign bodies.

With percussion The abdominal wall often reveals a tympanic sound of various shades. With flatulence it becomes loud, tympanic or atympanic, with coprostasis it becomes dull or dull.

Auscultation it is possible to establish the strength of peristaltic noise and characteristic acoustic data.

Rectal examinations in carnivores it is done with a finger. The condition of the rectal mucosa, the properties of the contents, and the condition of the anal glands, which are located in the final part of the rectum on the sides of the anus, are determined.

Rice. 53. Thoracic and abdominal cavities of the dog (right side):

1-13 - ribs; a, a", a" - right lung; b - pericardium; V- liver; g - diaphragm; d- right kidney; e - duodenum; and - cecum; h - pancreas; and - loops of small intestines; To - bladder; l- prostate; m - colon and rectum

These are two oval-shaped glands, measuring from 1 to 3 cm. Their excretory ducts exit onto the skin in the lower part of the anus.

Study of the intestines in birds. The duodenum originates from the anterior part of the muscular stomach, located on the left in the lower posterior part of the abdominal cavity. It forms a loop in which the pancreas is located. The jejunum is folded into small loops, adjacent to the right abdominal wall, then passes into the ileum, which is connected to both cecums, whose apices are directed backward and, together with the loop of the duodenum, extend to the posterior edge of the muscular stomach. The rectum is located under the spine and ends in the cloaca, into which the ureters and excretory tracts of the genital organs open; in young birds, the duct of Fabricius’ bursa.

An increase in abdominal volume is observed with vitelline peritonitis, dropsy, liver damage, and accumulation of gases. To examine the cloaca, spread its edges with your fingers and examine the condition of the mucous membrane. The muscular stomach is palpated in the lower posterior region of the abdomen on the left, and the intestinal loops are palpated behind the end of the sternum and on the right behind the last rib in the cloaca. When contents accumulate, individual parts of the intestine are found to be compacted.

Palpation and percussion accumulation of fluids in the abdominal cavity can be detected.

Rectal examinations swipe with a finger when indicated (suspicion of tumors, egg retention). The finger can pass from the cloaca to the rectum. The opening of the oviduct is located on the left side in the depths of the cloaca, and the entrance to the rectum is on the right.