Pancreas

Pancreas pancreas) - digestive iron with exocrine (exocrine) and vnutricletocny (endocrine) functions.
Anatomy. The pancreas is located in the abdomen behind the stomach at the level of 1,11 lumbar vertebrae (Fig). The weight of her 70-80, it distinguishes between head, body and tail.

pancreas structure The topography of the pancreas:
1 - liver;
2 - the celiac trunk;
3 - the tail of the pancreas;
4 - body;
5 - duct;
6 - head;
7 - big nipple duodenal ulcer;
8 - small nipple duodenal ulcer;
9 - extension of the pancreatic duct;
10 - the common bile duct.

The head of the pancreas is located in an arc of the duodenum. Pancreatic duct flows in most cases, after connecting to the common bile duct into the duodenum on her big nipple. The tail is in contact with the spleen. The body of the pancreas, which have the form of a triangular prism, front covered by the peritoneum. The pancreas blood supply is carried out through the top and bottom pancreatic-duodenal artery. The outflow of blood is brought into the system of portal vein. Innerviruetsya pancreas branches celiac, superior mesenteric, hepatic and splenic plexus.
Exocrine the part of the pancreas is a complex alveolar-tubular glands (see Gland). Its parenchyma consists of multiple segments, separated from each other by a layer of connective tissue. Most segments of the pancreas are presented limit secretory departments - the acinus, cells which produce pancreatic juice. In addition, in the parenchyma of the pancreas are clusters of cells (islets of Langerhans), richly supplied with blood vessels and not having excretory ducts, i.e. with internal secretion.
Physiology. External secretion of the pancreas is periodic selection in the duodenum pancreatic juice, which plays a significant role in the processes of digestion.
Pancreatic juice (see) contains the following enzymes: amylase (see), lipase (see Enzymes) and trypsin (see).
Secretion of pancreatic juice is regulated by the nerve (the wandering and sympathetic nerves)and humoral mechanisms. Secretion of pancreatic juice associated with food intake, and the works of I. P. Pavlov with employees found that different composition of the food causes the selection is diverse in scope and content of the enzyme pancreatic juice.
Significant sokogonnym action have vegetable broths, carbohydrates, lower - fat and low - protein.
The most powerful agent of secretory activity of the pancreas is a hydrochloric acid of the gastric juice, which when entering the small intestine activates the selection by the cells of the intestinal mucosa special substances - secretin (stimulates the formation of the liquid part of the secret of the pancreas) and pancreozymin (affects the production of enzymes pancreatic juice).
Of medicinal substances enhance the secretion of the pancreas pilocarpine, morphine, vitamin a, magnesium sulfate, and inhibit the secretion of histamine and atropine.
Vnutricletocny function is to develop pancreatic gland hormones insulin and glucagon, which play a great role in regulation of carbohydrate and lipid metabolism. Insulin is produced in beta-cells of the islets of Langerhans. Under the influence of his fixation of glycogen in the liver, the uptake tissues of sugar from the blood and reduction of lipemia.
Glucagon is secreted in the alpha cells of the islets of Langerhans and effect on blood sugar opposite than insulin.
Another function, which is attributed to the alpha cells,is participating in the development of lipotropic substances - lipokaina, prevent fatty liver.

Pancreas pancreas) is a large digestive gland, has mixed function. Most cancer - exocrine, produce a secret, which lead to the channel allocated to the duodenum. Parenchyma, P. W. immured group of cells that produce hormones. This is part of the endocrine gland - the islets of Langerhans (printing. Fig. 3).

pancreas
Fig. 1. Pancreas (the peritoneum partially removed allocated duct pancreas, duodenum opened): 1 - ductus choledochus; 2 - v. portae; 3 - a. hepatica propria; 4 - plexus; coeliacus; 5 - truncus coellacus; 6 - nodi lymphatic! coeliaci; 7 - a. gastroduodenalis; 8 - a. lienalis et plexus lienalis; 9 - nodi lymphatici pancreaticolienales; 10 - lien; 11 - ductus pancreaticus; 12 - a. mesenterica sup. et plexus mesentericus sup.; 13 - v. mesenterica sup.; 14 - a. et v. pancreaticoduodenal Inf.; 15 - papilla duodeni major; 16 - papilla duodeni minor; 17 - ductus pancreatlcus accessorius; 18 - duodenum; 19 - a. et v. pancreaticoduodenal sup.; 20 - ren dext.; 21 - gl. suprarenalis dext.; 22 - gl. suprarenalis sin.; 23 - ren sin.; 24 - ramus pancreaticus (a. lienalis).
Fig. 2. Pancreas (low magnification): 1 - terminal departments glands; 2 - the islet of Langerhans; 3 - midorikawa connective tissue; 4 - Medakovic excretory duct.
Fig. 3. The islet of Langerhans (large increase): 1 - a-cells; 2 - In-cell; 3-cell, deprived of granules (C cells).
Fig. 4. Centralnaya cells.


Embryology
Pancreas develops of two germs. Dorsal is a protrusion of the duodenum, which is inserted between the sheets dorsal mesentery of the stomach. The ventral root of the smaller size, shape and diverticular primary bile duct ventral from bookmarks liver.
At the turn of the stomach and duodenum both embryo are connected, and from ventral of primordial germ develop only the lower part of the head, P. W. and hooked process. Ductless both rudiments merge in the area of the head. Proximal part of the core definitive flow becomes excretory duct of ventral Bud. Sometimes persists and the proximal part of the exhaust duct dorsal nucleus of the latter in the form of incremental pancreatic duct adults.
The parenchyma of the pancreas develops from terminal kidney - branching ferrous tubes. Reproduction of epithelial cells leads to the formation acini associated General collective canals. From acini are the segments of the pancreas. On 3rd month of fetal life, the part of the kidney is separated from the primary epithelial tubes, formed isolated from the excretory ducts Islands cell - endocrine component P. W.

Anatomy
The pancreas is located in the retroperitoneal space across the spine at the level of the first lumbar vertebra in the form of a flattened strand a 15-25 cm and width 3-9 see (in the head), of a thickness of 2-3 cm; weight 70-80, the Thicker the right part - the head of the pancreas (caput) - bordered duodenum, stretching out in it formed a loop. Narrowed left part of the tail (cauda) - contact with the spleen (printing. Fig. 1). Body P. W. (corpus), having a form of a triangular prism, covered front parietal peritoneum. Between P. W. and stomach toward the front there is a narrow slit - entrance into the cavity greater omentum.
Ready secret exocrine part of the pancreas is going into the pancreatic duct (ductus pancreaticus), stretching along the entire gland from the tail to the head. Duct this opens with relevanssi duct (ductus choledochus) on top of a large (Vater) the nipple in descending Department of the duodenum. Extension duct P. W. (ductus accesorius, if he does not fall into the main canals, offer small duodenal papilla.

Fig. 1. Pancreatic arteries: 1 - aorta; 2 - truncus celiacus; 3 - a. lienalis; 4 - rr. lienales a. lienalis; s - rr. pancreatici; 6 - a. mesenterica sup.; 7-a. pancreaticoduodenalis Int.; s - a. pancreaticoduodenalis sup.; 9 - a. gastroepiploica dext.; 10 - a. gastroduodenalis; 11 - a. hepatica propria; 12 - a. hepatica communis.

P. W. gets the blood supply (Fig. 1) through the upper and lower pancreatic-duodenal artery (aa. pancreaticoduodenal sup. et inf.), originating from the system splanchnic (top) and superior mesenteric (bottom) of the arteries. Join them dorsal, bottom, big and caudal pancreatic artery is a branch of the splenic artery, which should be at the top P. W. The outflow of blood is on the same veins into the system of portal vein. Lymph flow from P. W. takes place through regional pancreatic-splenic lymph nodes in the course of the splenic artery, as well as through the pyloric and verhnebureinsky nodes.
Innerviruetsya pancreas branches and celiac verkhnebureinsk plexus (plexus celiacus et plexus mesentericus sup.), with a membership that includes sensitive fiber - peripheral processes of the cells of the spinal units and cells sensitive components of the vagus nerve, and the preganglionarnah and postganglionarnyh fibre vegetative nervous system.

Histology
The internal structure of the pancreas adult characterized by small delicately. From a thin connective tissue capsule of the gland depart layer separating segments and containing blood vessels and nerves. Vnutritrekovye ducts lined cubic epithelium, collect the secret of the insertion of tubes, the thin wall which is built of flat epithelial cells. Magdalsophia ducts, where flows are many vnutriposelkovykh covered inside with cylindrical epithelium, which is also the lining of the main and additional ducts.
Typical composition of the pancreas as complex alveolar cancer violated by the islets of Langerhans. Usually it's the cell accumulation in the form of balls with a diameter of up to 0.2-0.3 mm (printing. Fig. 2 and 3). Sometimes islet cells are diffuse in the form of fibers, separated by a sine waves, but they can easily be distinguished by colour and lack of communication with the excretory ducts. The main types of cells in the islets - alpha-cells (type a)that produce glucagon, and beta-cells (type), which produce insulin,- differ in properties contained in their cytoplasm granules.
Exocrine cells of the pancreas (Tsentralnaya cells) - heteropolar facing the tip into the cavity of atinusa (printing. Fig. 4). They have a relatively large core, rich in chromatin, and the cytoplasm, entirely permeated by membranes.
Cytochemistry and ultrastructure. In the cytoplasm of exocrine pancreatic cells differentiate membrane granular endoplasmic reticulum, forming the system of parallel channels and tanks. The lipoprotein wall tubules have a thickness of 40-60 A. Cavity tubules and tanks are the size of 800 and above, depending on the functional state of the cell. On the surface membranes are numerous submicroscopic granules - ribosome, which has dimensions of 150-300 A. They are composed of RNA and proteins. In exocrine cells is well developed complex Golgi - granulema endo plasmatic network. Mitochondria in the size 0,5-7,0 MK lie in the basal part of the exocrine cells. Christa in the mitochondria of the cells of the pancreas are more numerous than in cells of other organs.
The secret synthesized exocrine cells, contains a great number of different enzymes: alpha - and beta-amylase, Maltese, lipase, cholesterol esterase, trypsin, himotripsin, peptidase, ribonuclease, elastase, collagenase and other
In the secretion of these enzymes involved all the cell structure. Precursor chemicals secret - appear in the expanding cavities granular endoplasmic reticulum. Granules secret formed in the vacuoles of the Golgi complex. After that, they move in apical parts of cells, where and accumulate in the form of granules of Imogene.