What are the digestive glands in the human body? Digestive system glands

The ducts of the digestive glands open into the lumen of the digestive canal.

The largest of these are the salivary glands (parotid, sublingual and submandibular), as well as the liver and pancreas.

The ducts of the salivary glands, small and large, open into the oral cavity. Small salivary glands are named according to their location: palatine, labial, buccal, lingual. There are three pairs of large salivary glands: parotid, submandibular and sublingual. By the nature of the secreted secretion (saliva), the salivary glands are divided into protein (serous), mucous and mixed. The saliva contains enzymes that carry out the primary breakdown of food carbohydrates.

Liver is the largest gland (Fig. 10). The 1.5 kg weight serves several important functions. As a digestive gland, the liver forms bile, which flows into the intestines to aid digestion. A number of proteins are formed in the liver (albumin, globulin, protobin), here the conversion of glucose into glycogen takes place, the neutralization of a number of putrefaction products in the colon (indolo, phenol). It is involved in the processes of hematopoiesis and metabolism, and is also a blood depot.

The liver is located in the right hypochondrium and in the epigastric region. On the liver, the diaphragmatic (upper) and visceral (lower) surfaces, as well as the lower (anterior) edge, are distinguished.

Diaphragmatic surface facing not only upward, but also somewhat forward and adjacent to the lower surface of the diaphragm.

Sagittally located crescent ligament, the upper surface of the liver is divided into two parts, of which the right is much larger than the left.

Visceral surface turned, not only to the bottom, but also a little back. There are three grooves on it, from which they go sagittally, and the third connects to each other in the transverse direction. The furrows limit each other by 4 lobes: right, left, square and caudate, of which the first two are subdivided into segments. The square lobe is located in front of the transverse groove, and the caudate is located behind it. The transverse groove is located in the center, it is called gate of the liver. The portal vein, its own hepatic artery, nerves enter the gate of the liver, and the common hepatic duct and lymphatic vessels exit.

Figure 10 - Duodenum (A), liver (B, bottom view), pancreas (C) and spleen (D).

1 - upper part; 2 - descending part; 3 - horizontal part; 4 - ascending part; 5 - the right lobe of the liver; 6 - the left lobe of the liver; 7 - square share; 8 - caudate lobe; 9 - gallbladder; 10 - round ligament of the liver; 11 - inferior vena cava; 12 - gastric depression; 13 - duodenal (duodenal) impression; 14 - colon-intestinal impression; 15 - renal impression; 16 - common bile duct; 17 - the head of the pancreas; 18 - the body of the pancreas; 19 - the tail of the pancreas; 20 - pancreatic duct; 21 - accessory pancreatic duct.

The right longitudinal groove in its anterior section expands and forms a fossa in which it is placed gallbladder. In the posterior part of this groove there is an extension for the inferior vena cava. The left longitudinal groove serves as a passageway round ligament of the liver, which is an overgrown umbilical vein that functions in the fetus. In the posterior part of the left longitudinal sulcus is the venous ligament, which stretches from the round ligament to the inferior vena cava. In the fetus, this ligament functions as a duct through which blood from the umbilical vein flows directly into the inferior vena cava.

Lower(anterior) edge of the liver is sharp. He has clippings where the bottom of the gallbladder and the round ligament of the liver lie.

The entire liver is covered by the peritoneum. The exception is the posterior edge of the liver, where it grows together directly with the diaphragm, the gate of the liver, as well as the depression formed by the gallbladder.

By its structure, the liver - it is a complexly branched tubular gland, the excretory ducts of which are the bile ducts. Outside, the liver is covered with a serous membrane, represented by the visceral layer of the peritoneum. Under the peritoneum is a thin dense fibrous membrane, which penetrates through the gates of the liver into the substance of the organ, accompanying the blood vessels, and together with them forms interlobular layers.

The structural unit of the liver is lobule- formation of an approximately prismatic shape. There are about 500,000 of them. Each lobule consists, in turn, of the so-called hepatic tracts, or trabeculae, which are located in radii with respect to the central vein between the blood capillaries (sinusoids) flowing into it. The hepatic tracts are built of two rows of epithelial cells (hepatitis), between which there is a bile capillary. The hepatic tracts are a kind of tubular glands from which the liver is built. The secret (bile) secreted through the bile capillaries into the interlobular ducts, then enters the common hepatic duct leaving the liver.

The liver receives blood from the hepatic artery proper and the portal vein. The blood flowing from the stomach, pancreas, intestines and spleen through the portal vein is purified from harmful chemical impurities in the liver lobules. The presence of through holes in the walls of the sinusoids provides blood contact with hepatocytes, which absorb some substances from the blood and release others into it. The blood that has changed its composition is collected in the central veins, from where it enters the inferior vena cava through the hepatic veins.

Gallbladder - hepatic cells produce up to 1 liter of bile per day, which enters the intestines. The reservoir in which bile accumulates is the gallbladder. It accumulates and concentrates bile due to the absorption of water. Located in front of the right longitudinal sulcus of the liver. It is pear-shaped. Its capacity is 40-60 ml. Length 8-12 cm, width 3-5 cm. It distinguishes between the bottom, body and neck. The neck of the gallbladder faces the gate of the liver and continues into the cystic duct, which merges with the common bile duct, it flows into the duodenum.

The cystic duct, depending on the phase of digestion, conducts bile in two directions: their liver into the gallbladder and their gallbladder into the common bile duct.

Summary of the topic

Digestion is served by three groups of glands:

1) unicellular intraepithelial glands (goblet exocrinocytes, Paneth apical granular cells;

2) intramural simple tubular glands of the gastric mucosa and more complex branched glands of the submucosa of the esophagus and duodenum 12;

3) large extraorganic salivary glands, pancreas and liver.

Complex salivary glands ... The excretory ducts of three pairs of complex salivary glands open into the oral cavity. All salivary glands develop from the stratified squamous epithelium lining the oral cavity of the embryo. They consist of secretory end sections and pathways that excrete the secret. According to the structure and nature of the secreted secretion, the secretory departments are of three types: proteinaceous, mucous, protein-mucous. The excretory tracts of the salivary glands are divided into interlobular ducts, striated, intralobular, interlobular excretory ducts and the common excretory duct. By the mechanism of secretion separation from cells, all salivary glands are merocrine.

Parotid glands ... Outside, the glands are covered with a dense loose connective tissue capsule. The gland has a pronounced lobular structure. By its structure, it is a complex alveolar branched gland, protein by the nature of the secreted secretion. In the lobules of the parotid gland are the terminal protein sections, intercalated ducts, striated ducts (salivary tubes) and intralobular ducts.

It is believed that in the striated sections, the secret is diluted with water and inorganic substances. It is believed that salivary hormones such as saliparotin (regulates the balance of phosphorus and calcium in the bone), nerve growth factor, insulin-like factor, and epithelial growth factor are secreted in these sections. The intralobular excretory ducts are covered with a bilayer epithelium, the interlobular excretory ducts are located in the interlobular connective tissue. As the excretory ducts strengthen, the bilayer epithelium gradually becomes multilayer. The common excretory duct is covered with stratified squamous non-keratinizing epithelium. Its mouth is located on the surface of the buccal mucosa at the level of the 2nd upper large molar.

Submandibular glands... In the submandibular glands, along with purely proteinaceous, mucous-protein end sections are formed. In some parts of the gland, mucous membrane of the intercalated ducts occurs, from the cells of which the mucous cells of the terminal sections are formed. It is a complex alveolar, sometimes tubular-alveolar, branched protein-mucous gland. From the surface of the iron is dressed with a connective tissue capsule. The lobular structure in it is less pronounced than in the parotid gland. In the submandibular gland, the end sections predominate, which are arranged in the same way as the corresponding end sections of the parotid gland. The mixed end sections are larger. They consist of two types of cells - mucous and protein (protein half moon Gianuci). The intercalated ducts of the submandibular gland are less branched and shorter than the parotid gland. The striated ducts in the submandibular gland are very well developed. They are long and highly branched. The epithelium of the excretory ducts is lined with the same epithelium as in the parotid gland. The main excretory duct of this gland opens next to the duct of the paired hyoid gland at the anterior edge of the frenum of the tongue.

Sublingual gland is a mixed, mucous-protein gland with a predominance of mucous secretion. It contains the following end secretory sections: mucous, proteinaceous and mixed with a predominance of mucous membranes. Protein end sections are few in number. The mucous end sections are composed of characteristic mucous cells. Myoepithelial elements form the outer layer in all end sections, as well as in the intercalated and striated ducts, which are extremely poorly developed in the hyoid gland. Connective tissue intralobular and interlobular septa are better expressed than in the two types of previous glands.

Pancreas... In the pancreas, a distinction is made between the head, body and tail. The gland is covered with a thin transparent connective tissue capsule, from which numerous interlobular septa, consisting of loose connective tissue, extend into the depths of the parenchyma. Interlobular excretory ducts, nerves, blood and lymphatic vessels pass through them. Thus, the pancreas has a lobular structure.

Pancreas consists of an exocrine section (97% of its mass) and an endocrine section formed by the islets of Langerhans. The exocrine part of the gland produces a complex digestive secret - pancreatic juice, which flows through the excretory ducts into the duodenum. Trypsin, chemotrypsin, carboxylase act on proteins, lipolytic enzyme lipase breaks down fats, amylolytic enzyme amylase - carbohydrates. The secretion of pancreas is a complex neurohumoral act, in which a special hormone, secretin, produced by the mucous membrane of the duodenum and delivered to the gland through the bloodstream, plays an important role.

General principle of organization exocrine department the pancreas is similar to the salivary glands. Its end sections look like vesicles, from which the interlobular excretory ducts originate, passing into the intralobular, and those, in turn, into the interlobular and common excretory duct, which opens together with the hepatic duct on the ventral wall of the duodenum. For the common hepato-pancreatic duct, the sphincter of Oddi is formed. The peculiarity is the absence of a striated section and the monolayer of the epithelial lining throughout. The structural and functional unit of the exocrine part of the pancreas is the acinus, which includes the terminal and insertion sections. There are different types of relationships between the terminal and insertion sections, in connection with which the concepts of simple and complex acinus are distinguished.

Endocrine part the body produces the hormone insulin, under the action of which in the liver and in muscle tissue, glucose coming from the blood is converted into the polysaccharide glycogen. The effect of insulin is to lower blood sugar levels. In addition to insulin, the pancreas produces the hormone glucagon. It ensures the conversion of liver glycogen into simple sugars and thus helps to increase the amount of glucose in the blood. Thus, these hormones are essential in the regulation of carbohydrate metabolism in the body. Morphologically, the endocrine part of the pancreas is a collection of special cell groups that lie in the form of islets (islets of Langerhans) in the parenchyma of the gland. Their shape is most often round, less often islets of irregular angular outlines are found. There are much more insulocytes in the tail of the gland than in the head. The stroma of the islets is made up of a delicate reticular network. The islets are usually separated from the surrounding glandular parenchyma by a thin connective tissue sheath. In the human pancreas, using special staining methods, several main types of islet cells have been discovered - cells A, B, PP, D, Dg The bulk - 70% of pancreatic islets - are B cells (produce insulin). They are cubic or prismatic. Their nuclei are large and take dyes well. The cytoplasm of insulocytes contains granules that are readily soluble in alcohols and insoluble in water. A distinctive feature of B cells is their close contact with the walls of sinusoidal capillaries. These cells form compact cords and are more often located along the periphery of the islet. About 20% of all human islet cells are acidophilic endocrinocytes A (produce glucagon). These are large, round or angular cells. The cytoplasm contains relatively large granules, readily soluble in water, but insoluble in alcohols. The nuclei of the cells are large, pale in color, since they contain a small amount of chromatin. The rest of the endocrinocytes account for no more than 5%. PP-cells secrete pancreatic peptide, D-cells - somatostatin, D-cells - VIP hormone.

Age-related changes in the human pancreas are clearly detected in the process of development, growth and aging of the body. Thus, the relatively high content of young connective tissue in newborns rapidly decreases in the first months and years of life. This is due to the active development of exocrine glandular tissue in young children. The amount of islet tissue also increases after the birth of the baby. In an adult, the ratio between glandular parenchyma and connective tissue remains relatively constant. With the onset of old age, the exocrine tissue undergoes involution and partially atrophies. The amount of connective tissue in the organ increases significantly, and it takes the form of adipose tissue.

Liver- the largest human digestive gland. Its weight is 1500-2000 g. The liver is a vital organ that performs the following functions :1) metabolic - synthesis of blood proteins (albumin, globulin), blood coagulation factors (fibrinogen, prothrombin), hc leterin; 2) protective - chemical protection against harmful substances (detoxification) is carried out using a smooth endoplasmic reticulum; the cellular type of defense is performed by hepatic macrophages - Kupffer's cells; 3) depositing - the formation and accumulation of glycogen (mainly at night), the deposition of a number of vitamins (A, D, C, K, PP); 4) excretory - the formation of bile and its excretion into the duodenum; 5) hematopoietic - occurs during intrauterine development, at 5-6 weeks extravascular foci of erythropoiesis, granulocytopoiesis, megakaryocytopoiesis appear.

The liver is covered with a dense connective tissue capsule, has a lobular organization. In the human liver, there is little connective tissue, so the lobulation is not as noticeable as in the liver of a pig. In this animal, the lobule is surrounded on all sides by connective tissue and is clearly individualized. In humans, areas of connective tissue are visible only in the tetrad region. The organization of the liver can be distinguished three structural and functional units : 1) hepatic lobule - a hexagonal prism, through the center of which the central vein passes, collecting blood from sinusoidal capillaries. Next to the lobule is a tetrad (portal tract), which consists of an interlobular artery (a branch of the hepatic artery of the systemic circulation), an interlobular vein (a branch of the portal vein), an interlobular bile duct (into which bile flows from the bile capillaries of the lobule) and an interlobular lymphatic vessels. Due to the small amount of connective tissue in the human liver, complex lobules are formed, in which hepatocytes in the hepatic trabeculae, without interruption, pass from one lobule to another; 2) portal lobule and 3) hepatic acinus ... In all three structural and functional units of the liver, there are hepatic tracts formed from hepatocytes and sinusoidal capillaries located between the tracts. Both lie parallel to each other and radially relative to the central vein. Numerous Kupffer cells (macrophages) are found in the wall of the sinusoidal capillary between endothelial cells. The Disse space is located between the hepatic beams and the wall of sinusoidal capillaries: it contains lipocytes (Ito cells), fibroblasts, processes of Kupffer cells, pericytes, pit cells, mast cells. The vascular bed of the liver is represented by the blood flow system - the portal vein and hepatic arteries, lobar vessels, segmental, interlobular, intralobular, sinusoidal capillaries. The system of blood outflow includes the central veins, podlobnye, (collecting) veins, segmental lobar enter the vena cava.

Chronocard

1. Organizational part with theme motivation - 5 min.

2. Programmed control - 10 min.

3. Interview-conversation - 35 min.

4. Explanation of drugs - 10 min.

5. Break - 15 minutes.

6. Control over the independent work of students. Assistance in working with drugs - 65 min.

7. Summing up. Album check - 10 min. Lab time: 3 hours.

Similar information.

Digestive glands include the salivary glands, stomach glands, liver, pancreas, and intestinal glands.

The glands, the ducts of which open into the oral cavity, include the small and large salivary glands. Small salivary glands, labial (glandulae labiales); buccal (glandulae buccales); painting (glandulae molares); palatine (dlandulae palatinae); lingual (glandulae linguales) are located in the thickness of the mucous membrane lining the oral cavity. Large salivary glands, paired, are located outside the oral cavity, but their ducts open into it. TO these glands include the parotid, sublingual, and submandibular glands.

The parotid gland (glandula parotidea) has a conical shape. The base of the gland faces outward, and the apex enters the postmaxillary fossa. Above, the gland reaches the zygomatic arch and the external auditory canal, behind - the mastoid process of the temporal bone, below - the angle of the lower jaw. The excretory duct (ductus parotideus) passes below the zygomatic arch along the outer surface of the masticatory muscle, then pierces the buccal muscle and opens in the mouth of the mouth with an opening at the level of the second upper large molar.

Submandibular gland (glandula submandibularis) - located in the submandibular triangle of the neck at the posterior edge of the jaw-sublingual muscle, a duct (ductus submandibularis) emerges from the gland, which goes around the posterior edge of this muscle, runs along the medial edge of the hyoid gland and opens * on the sublingual papilla ...

The sublingual gland (glandula sublingualis) is located above the jaw-hyoid muscle, under the mucous membrane, forming a sublingual fold. Several small ducts emerge from the gland, opening into the oral cavity along the hyoid fold and a large sublingual duct, either merging with the duct of the submandibular gland or opening independently next to it on the sublingual papilla.

The liver (hepar) is the largest gland, its weight in humans reaches 1500 g. The liver is located in the abdominal cavity, under the diaphragm, in the right hypochondrium. Its upper border along the right midclavicular line is at the level of the IV intercostal space. Then the upper border of the liver goes down to the X intercostal space along the right mid-axillary line. On the left, the upper border of the liver gradually descends from the intercostal space along the mid-thoracic line to the level of attachment of the VIII left costal cartilage to the VII rib. The lower border of the liver runs along the edge of the costal arch on the right, in the epigastric region, the liver is adjacent to the posterior surface of the anterior abdominal wall. In the liver, a large right and a smaller left lobe and two surfaces are distinguished - the diaphragmatic and the visceral. On the visceral surface are the gallbladder (vesica fellea) (reservoir of bile), the gate of the liver (porta hepatis), through which enter: the portal vein, hepatic artery and nerves, and exit: the common hepatic duct and lymphatic vessels. On the visceral surface of the right lobe, square (lobus quadratus) and caudate (lobus caudatus) are distinguished. The liver is fixed to the diaphragm: the falciform ligament (lig.falciforme), the coronary ligament (lig.coronarmm), which along the edges forms the right and left triangular ligaments (ligg.triangulare dextrum et triangulare sinistrum). The round ligament of the liver (lig. Teres hepatis) is an overgrown umbilical vein, starts from the navel, passes along the notch of the round ligament (incisura lig. Teretis), enters the lower edge of the sickle ligament and then reaches the gate of the liver. On the posterior surface of the right lobe, the inferior vena cava passes to which the ligamentous venous (lig.venosum) is attached - an overgrown venous duct that connects the umbilical vein in fetuses with the inferior vena cava. The liver performs a protective (barrier) function, it neutralizes the poisonous decay products of proteins and toxic substances that are absorbed from the intestine into the blood and formed as a result of the vital activity of microbes in the large intestine. Poisonous substances in the liver are neutralized and excreted from the body in urine and feces. The liver is involved in digestion by secreting bile. Bile is produced by liver cells constantly, and enters the duodenum through the common bile duct only if there is food in it. When digestion stops, bile through the cystic duct accumulates in the gallbladder, where, as a result of water absorption, the concentration of bile increases 7-8 times.

The gallbladder (vesica fellea) is located in the fossa on the visceral surface of the liver. It contains the bottom (fundus vesicae felleae), the body (corpus vesicae felleae) and the neck (collum vesicae felleae), which continues into the cystic duct (ductus cysticus) flowing into the common hepatic duct, formed by the fusion of the right and left hepatic ducts (duxter hepaticus de et sinister). The common hepatic duct passes into the common bile duct (ductus choledochus) located between the leaves of the hepatic duodenal ligament anterior to the portal vein and to the right of the common hepatic artery. The common bile duct runs behind the upper part of the duodenum and the head of the pancreas, pierces the intestinal wall, merges with the pancreatic duct, and opens at the apex of the greater duodenal papilla.

The pancreas (pancreas) is located in the abdominal cavity, behind the stomach at the level of bodies I-II of the lumbar vertebrae, goes to the left and up to the gate of the spleen. Its mass in an adult is 70-80 g. It has a head (caput pancreatis), a body (corpus pancreatis) and a tail (cauda pancreatis). The pancreas is an external and internal secretion gland. As a digestive gland, it produces pancreatic juice, which flows through the excretory duct (ductus pancreaticus) into the lumen of the descending part of the duodenum, opening on its large papilla, having previously connected with the common bile duct.

The peritoneum (peritoneum) forms a serous sac, which in women communicates with the external environment through the fallopian tubes, uterine cavity and vagina. The peritoneum consists of parietal and intra-neural layers.

The parietal leaf lines the walls of the abdominal cavity, which is bounded from above by the diaphragm, from the back - by the lumbar spine, square and iliopsoas muscles, in front and sides - by the abdominal muscles, from below - by the perineum. From the inside, the walls of the abdominal cavity are lined with an intra-abdominal fascia, between which and the parietal leaf of the peritoneum is fatty tissue, which is highly developed on the posterior abdominal wall around the internal organs located here, forming the retroperitoneal space. The intrinsic leaflet lines the internal organs of the abdominal cavity. The slit space between the parietal and intraosseous sheets of the peritoneum is called the cavitas peritonei, filled with serous fluid, which moisturizes the surfaces of the organs, facilitating their movement. The parietal sheet of the peritoneum in the places of transition to the internal organs forms ligaments and mesentery. The abdominal organs can be covered with the peritoneum from one, three, or all sides. On one side (extraperitoneally) covered: pancreas, duodenum, empty bladder. The kidneys and adrenal glands are located retroperitoneally. On three sides (mesoperitoneally) covered: the ascending and descending colon, the middle third of the rectum, the liver and the filled bladder. All sides (intraperitoneally) covered: stomach, skinny, ileal, blind, transverse colon, sigmaid and upper third of the rectum, appendix, spleen, uterus and fallopian tubes

The mesentery is formed by a duplication of the visceral sheets of the peritoneum, between which the blood, lymphatic vessels and nerves approach the organ.

From the lower surface of the diaphragm and the anterior wall of the abdomen, the sickle, coronary and round ligaments go to the liver, from which the peritoneum passes to the liver. In the area of ​​the gates of the liver, the sheets of the peritoneum pass to the stomach and duodenum, forming a small omentum (omentum minus). Covering the stomach in front and behind, the sheets of the peritoneum on its greater curvature grow together and free, but go down in front of the loops of the small intestine and the mesentery of the transverse colon, forming a large omentum, consisting of 4 sheets of the peritoneum. The greater omentum (omentum majus) grows together with the mesentery of the transverse colon, limits the omental bursa (bursa omentalis) behind the stomach and the lesser omentum, which, through the foramen epiploicum, communicates with the pregastric bursa, into which the hepatic bursa opens.

The upper, middle and lower floors are distinguished in the abdominal cavity. The upper floor occupies the space from the diaphragm from above to the mesentery of the transverse colon from below. The middle floor is bounded by the mesentery of the transverse colon from above and the entrance to the small pelvis from below. The lower floor of the abdominal cavity corresponds to the pelvic cavity. The peritoneum from the middle floor of the abdominal cavity descends to the lower floor, passing from the walls of the small pelvis to the pelvic organs, forming indentations. In men - vesicoureteral, and in women - vesicouterine and rectal-uterine.

The liver consists of two lobes: its right lobe is located in the right hypochondrium, the left - in the epigastric region, that is, under the sternum.

Liver function

Barrier function

In lower animals (mollusks), the primary epithelial elements of the liver form, as it were, cell cases around small branches of the intestine, so that all substances from the intestines can enter the blood stream only through the cells of this case. During the evolutionary development of animals, this conglomerate of liver cells separates into a separate organ, closely, however, connected with the intestine through the portal vein.

Due to this arrangement, the liver acts as a barrier through which everything that is absorbed from the intestines passes. In this regard, the liver performs very important functions in the body.

Actually, the barrier function of the liver consists in the fact that some poisonous substances that accidentally enter the body (mercury, lead, etc.) are retained in it and are not passed into the blood stream. Poisonous substances contained in food absorbed from the gastrointestinal tract enter the liver through a vein and are rendered harmless by its cells.

It neutralizes the poisonous substances formed in the large intestines during the decay of proteins (phenol, indole). In the liver, from these substances, slightly toxic and easily soluble compounds are formed, which are easily excreted from the body.

Metabolic function

The liver plays a major role in carbohydrate metabolism. It synthesizes glycogen from glucose. A large amount of glycogen (over 10% of the liver's weight) can be deposited in the liver cells. The liver can also synthesize glycogen from volatile fatty acids (in ruminants), from lactic acid, and even from glycerol (for example, in hibernating animals).

Of particular importance is the insulin-excreting function of the under-stomach gland, since its violation leads to the development of diabetes mellitus, which is widespread. In a healthy person, the blood sugar content is 80-120 mg%, and in diabetes mellitus, its level can rise to 150-250 mg% or more.

With a normal blood sugar content, it is not excreted in the urine, in other words, there is no sugar in the urine of a healthy person. With an increase in blood sugar above 140-150 mg%, it begins to be excreted in the urine. At the same time, patients experience constant thirst and consume a lot of water. Due to the fact that the carbohydrates of the ingested food, without being absorbed by cells and tissues, are excreted in the urine, the patient quickly becomes hungry and has to eat often. Otherwise, the fats of the subcutaneous tissue, accumulated by the body in the form of reserves, and even proteins and fats in the composition of cells and tissues, undergoing decomposition, are converted into glucose and pass into the blood, and from there they are excreted in the urine. As a result, the patient loses weight, he has a general weakness, a decrease in working capacity.

ANATOMY AND PHYSIOLOGY OF THE DIGESTIVE GLANDS

SALIVARY GLANDS

There are large and small salivary glands in the oral cavity.

Three large salivary glands:

Parotid gland(glandula parotidea)

Its inflammation is mumps (viral infection).

The largest salivary gland. Weight 20-30 grams.

Located below and in front of the auricle (on the lateral surface of the mandible branch and the posterior edge of the masseter muscle).

The excretory duct of this gland opens in the vestibule of the mouth at the level of the second upper molar. The secret of this gland is proteinaceous.

Submandibular gland(glandula submandibularis)

Weight 13-16 grams. It is located in the submandibular fossa, below the maxillary - hyoid muscle. Its excretory duct opens at the sublingual papilla. The secret of the gland is mixed - protein - mucous.

Sublingual gland(glandula sublingualis)

Weight 5 grams, located under the tongue, on the surface of the jaw-hyoid muscle. Its excretory duct opens on the papilla under the tongue along with the duct of the submandibular gland. The secret of the gland is mixed - protein - mucous with a predominance of mucus.

Small salivary glands 1 - 5 mm in size, located throughout the oral cavity: labial, buccal, molar, palatal, lingual salivary glands (most of all palatine and labial).

Saliva

A mixture of the secretion of all salivary glands in the mouth is called saliva.

Saliva is a digestive juice produced by the salivary glands that works in the mouth. Per day, a person secretes from 600 to 1500 ml of saliva. The reaction of saliva is slightly alkaline.

Saliva composition:

1. Water - 95-98%.

2. Saliva enzymes:

- amylase - breaks down polysaccharides - glycogen, starch to dextrin and maltose (disaccharide);

- maltase - breaks down maltose up to 2 glucose molecules.

3. Mucus-like protein - mucin.

4. Bactericidal substance - lysozyme (an enzyme that destroys the cell wall of bacteria).

5. Mineral salts.

Food is in the oral cavity for a short time, and the breakdown of carbohydrates does not have time to end. The action of salivary enzymes ends in the stomach when the food lump is saturated with gastric juice, while the activity of saliva enzymes in the acidic environment of the stomach increases.

LIVER ( hepar )

The liver is the largest gland, red-brown in color, its weight is about 1500 g. The liver is located in the abdominal cavity, under the diaphragm, in the right hypochondrium.

Liver function :

1) is a digestive gland, forms bile;

2) participates in metabolism - in it, glucose is converted into a reserve carbohydrate - glycogen;

3) participates in hematopoiesis - blood cells die in it and plasma proteins are synthesized - albumin and prothrombin;

4) neutralizes poisonous decay products, supplied with blood, and products of colon putrefaction;

5) is a blood depot.

The liver secretes:

1... Shares: large right (it includes the square and caudate lobes) and less left;

2. Over ness : diaphragmatic and visceral.

On the visceral surface are located bilious bubble (bile reservoir) and liver gate . Through the gate are included: portal vein, hepatic artery and nerves, and come out: common hepatic duct, hepatic vein and lymphatic vessels.

Unlike other organs in the liver, in addition to arterial blood, venous blood flows through the portal vein from the unpaired organs of the gastrointestinal tract. The largest is the right lobe, separated from the left supporting sickle ligament , which passes from the diaphragm to the liver. At the back, the falciform ligament connects to coronary ligament , which is a duplication of the peritoneum.

On the visceral surface liver visible:

1 . Furrows - two sagittal and one transverse. The area between the sagittal grooves is divided by a transverse groove into two sites :

a) front - square fraction;

b) back - caudate.

In front of the right sagittal sulcus lies the gallbladder. In the back of it is the inferior vena cava. The left sagittal sulcus contains round ligament of the liver which, before birth, represented the umbilical vein.

The transverse furrow is called gated liver.

2. Depressions - renal, adrenal, colon - intestinal and 12-duodenal - intestinal

Most of the liver is covered by the peritoneum (mesoperitoneal location of the organ), except for the posterior surface adjacent to the diaphragm. The surface of the liver is smooth, covered with a fibrous membrane - glisson capsule... Interlayers of connective tissue inside the liver divide its parenchyma into lobules .

In the layers between the lobules are located interlobular branches of the portal vein, interlobular branches of the hepatic artery, as well as interlobular bile ducts. They form a portal area. - hepatic triad .

The hepatic capillary networks are formed endotheliocytic cells between which lie stellate reticulocytes, they are able to absorb substances circulating in it from the blood, capture and digest bacteria. The blood capillaries in the center of the lobule flow into central vein. Central veins merge and form 2 - 3 hepatic veins that fall into inferior vena cava... Blood passes through the capillaries of the liver several times in 1 hour.

Lobules are composed of liver cells - hepatocytes arranged in the form of beams. Hepatocytes in the hepatic tracts are arranged in two rows, each hepatocyte with one side in contact with the lumen of the bile capillary, and the other with the wall of the blood capillary. Therefore, the secretion of hepatocytes is carried out in two directions.

Bile flows from the right and left lobes of the liver along right and left hepatic ducts which combine into common hepatic duct... It connects to the gallbladder duct, forming a common bileduct, which passes in the lesser omentum and, together with the pancreatic duct, opens on the greater duodenal papilla of the duodenum.

Bile produced by hepatocytes continuously and accumulates in the gallbladder. Bile has an alkaline reaction, it consists of bile acids, bile pigments, cholesterol and other substances. A person produces from 500 to 1200 ml of bile per day. Bile activates many enzymes and especially the lipase of pancreatic and intestinal juices, emulsifies fats, i.e. increases the surface of interaction of enzymes with fat, it also enhances intestinal motility and has a bactericidal effect.

Bilious bubble (biliaris, vesica fellea)

Bile storage tank. It is pear-shaped. Capacity 40-60 ml. In the gallbladder, there are: body, bottom and neck. The neck continues into cystic duct, which connects to the common hepatic duct and forms the common bile duct. The bottom is adjacent to the anterior abdominal wall, and the body to the lower part of the stomach, duodenum and transverse colon.

The wall consists of mucous and muscular membranes and is covered by the peritoneum. The mucous membrane forms a spiral fold in the neck and cystic duct, the muscular membrane consists of smooth muscle fibers.

PANCREAS ( pancreas )

Inflammation of the pancreas - pancreatitis .

The pancreas is located behind the stomach. Weight 70-80 gr., Length 12-16 cm.

It contains:

Surfaces: front, back, bottom;

H asti : head, body and tail.

In relation to the peritoneum, the liver is located extraperitoneally(covered with the peritoneum from the front and partly from the bottom)

Projected :

- head- I-III lumbar vertebra;

- body- I lumbar;

- tail- XI-XII thoracic vertebra.

Behind glands lie: portal vein and diaphragm; on the top edge - splenic vessels; surrounds the head 12-duodenum.

The pancreas is a mixed secretion gland.

As an exocrine gland (exocrine gland) , it produces pancreatic juice, which through excretory duct excreted in the duodenum. The excretory duct is formed at fusion intralobular and interlobular ducts. The excretory duct merges with the common bile duct and opens on the large duodenal papilla, in its terminal section it has a sphincter - Odie's sphincter. Through the head of the gland passes accessory duct, which opens on the small duodenal papilla.

Pancreatic (pancreatic) juice has an alkaline reaction, it contains enzymes that break down proteins, fats and carbohydrates:

- trypsin and chymotrypsin breaks down proteins into amino acids.

- lipase breaks down fats to glycerin and fatty acids.

- amylase, lactase, maltase, break down starch, glycogen, sucrose, maltose and lactose to glucose, galactose and fructose.

Pancreatic juice begins to be secreted 2-3 minutes after the start of a meal and lasts from 6 to 14 hours, depending on the composition of the food.

As an endocrine gland (endocrine gland) , the pancreas has islets of Langerhans, whose cells produce hormones - insulin and glucagon... These hormones regulate the level of glucose in the body - glucagon increases, and insulin decreases blood glucose. With hypofunction, the pancreas develops diabetes .