Remark the last 5 years, I and my assistants had the opportunity to interview more than 5,000 patients with type 2 diabetes. Very often during the conversation I had to hear: So you are a doctor, can cure my pancreas? Unfortunately, not only patients, but even many doctors confuse the causes of type 1 and type 2 diabetes. The main difference of type 2 diabetes from the 1st is an absolutely healthy pancreas in the vast majority of patients with type 2 diabetes!
The main cause of type 1 diabetes is the death of beta cells responsible for insulin production in the body. In the case of diabetes mellitus type 2, the main pathogenetic mechanism for the development of this disease is a decrease in tissue sensitivity to insulin action (insulin resistance), which in 90% of cases of type 2 diabetes, is synthesized by the pancreas in normal and even elevated amounts.
Human pancreas (Latin pancreas) – the organ of the digestive system; coarse gland with exocrine and intrasecretory functions. The organ’s excretory function is realized by secreting pancreatic juice containing digestive enzymes. While producing hormones, the pancreas takes an important part in the regulation of carbohydrate, fat and protein metabolism.
The human pancreas is an elongated lobular formation of a grayish-pinkish hue and is located in the abdominal cavity behind the stomach, closely adjacent to the duodenum. The organ lies in the upper section on the posterior wall of the abdominal cavity in the retroperitoneal space, located transversely at the level of the bodies of the I – II lumbar vertebrae. The length of the gland of an adult is 14-22 cm, width 3-9 cm (in the head area), 2-3 cm thick. Body weight about 70-80 g.
In the pancreas secrete head, body and tail.
The head of the pancreas (caput pancreatis) is adjacent to the duodenum, located in its bend so that the latter covers the gland in the form of a horseshoe. The head is separated from the body of the pancreas by a groove in which the portal vein passes. From the head begins the additional (Santorini) pancreatic duct, which either merges with the main duct (in 60% of cases), or
independently flows into the duodenum
through the small duodenal papilla.
BODY OF THE PANCREAS
The body of the pancreas (corpus pancreatis) has a triangular (triangular) shape. In it there are three surfaces – front, back and bottom, and three edges – top, front and bottom. Anterior surface (facies anterior) facing anteriorly, to the posterior surface of the stomach, and somewhat upward; from the bottom it is bound by the front edge, and from above – by the top one. On the front surface of the body of the gland there is a bulge facing the stuffing bag – the stuffing tubercle.
The posterior surface (facies posterior) is adjacent to the spine, abdominal aorta, inferior vena cava, celiac plexus, and left renal vein. On the posterior surface of the gland there are special grooves in which the splenic vessels pass. The posterior surface is delimited from the anterior with a sharp upper margin along which the splenic artery passes. The lower surface (facies inferior) of the pancreas is oriented downwards and anteriorly and is separated from the posterior by a blunt posterior margin. It is located below the root of the mesentery of the transverse colon.
Tail of the pancreas
The tail of the pancreas (cauda pancreatis) has a cone-shaped or pear-shaped shape, going left and up, extending to the gates of the spleen. The main (wirsung) duct of the pancreas passes through its length and flows into the duodenum in its descending part on the large duodenal papilla. The common bile duct usually merges with the pancreatic and opens into the intestine there or next.
The head is projected onto the spine at a level ranging from the XII thoracic to the IV lumbar vertebrae. The body ranges from TXII to LIII; tail position ranges from TXI to LII.
The structure is a complex alveolar-tubular gland. From the surface, the organ is covered with a thin connective tissue capsule. The main substance is divided into lobules, between which there are connective tissue strands, enclosing the excretory ducts, vessels, nerves, as well as the nerve ganglia and lamellar bodies. The pancreas includes exocrine and endocrine parts.
The exocrine part of the pancreas is represented by pancreatic acini located in lobules, as well as a tree-like system of excretory ducts: intercalated and intralobular ducts, interlobular ducts, and finally the common pancreatic duct opening into the lumen of the duodenum.
Acinus of the pancreas is a structural and functional unit of the body. In the form of acinus is a rounded education with a size of 100-150 microns, in its structure it contains a secretory section and an inserted duct, giving rise to the entire system of organ ducts. Acini consists of two types of cells: secretory – exocrine pancreatocytes, in the amount of 8-12, and ductal – epithelial cells. The intercalated ducts pass into the inter-acinar ducts, which in turn flow into larger intra-lobular ones. The latter continue into the interlobular ducts, which flow into the common pancreatic duct.
The endocrine portion of the pancreas is formed lying between the acini pancreatic islets, or islets of Langerhans. The islands consist of cells – insulocytes, among which, based on the presence of granules of different physical, chemical and morphological properties, there are 5 main types:
insulin synthesizing beta cells ;
alpha cells producing glucagon;
delta cells that form somatostatin;
D1 cells that secrete VIP;
PP cells that produce pancreatic polypeptide.
In addition, the presence of insignificant number of cells containing gastrin, thyroliberin and somatoliberin in the islets has been shown by immunocytochemistry and electron microscopy. The islands are compact clusters penetrated by a dense network of fenestrated capillaries arranged in clusters or cords of intrasecretory cells. The cells are surrounded by layers of the capillaries of the islets, being in close contact with the vessels; most endocrinocytes are in contact with the vessels either through cytoplasmic processes or directly adjacent to them.
The pancreas is supplied with blood through the pancreatoduodenal arteries, which branch off from the superior mesenteric artery or from the hepatic artery (branch of the celiac trunk of the abdominal aorta). The superior mesenteric artery provides the lower pancreatoduodenal arteries, while the gastroduodenal artery (one of the terminal branches of the hepatic artery) provides the upper pancreatoduodenal arteries.
The arteries, branching into the interlobular connective tissue, form dense capillary networks intertwining the acini and penetrating the islets. Venous outflow occurs through the pancreatoduodenal veins, which flow into the splenic gland passing behind the gland, as well as other tributaries of the portal vein. The portal vein is formed after a fusion behind the body of the pancreas of the superior mesenteric and splenic veins. In some cases, the inferior mesenteric vein also joins the spleen behind the pancreas (in others, it simply connects to the superior mesenteric vein).
Lymphatic capillaries, starting around the acini and islets, flow into the lymphatic vessels, which pass near the blood vessels. Lymph is taken by pancreatic lymph nodes, located in the amount of 2-8 at the upper edge of the gland on its anterior and anterior surfaces.
Parasympathetic innervation of the pancreas is carried out by the branches of the vagus nerves, more right, sympathetic – from the celiac plexus. Sympathetic fibers accompany the blood vessels. In the pancreas there are intramural ganglia.
DEVELOPMENT AND AGE FEATURES OF THE PANCREAS
The pancreas develops from the endoderm and mesenchyme; its rudiment appears on the 3rd week of embryonic development in the form of protrusion of the embryonic intestinal wall, from which the head, body and tail are formed. Differentiation of the primordia to the excretory and inner secretory parts begins from the 3rd month of embryogenesis. Acini and excretory ducts are formed, the endocrine compartments are formed from the kidneys on the excretory ducts and are detached from them, turning into islets.
Vessels, as well as connective tissue elements of the stroma are developed from the mesenchyme. In newborns, the pancreas has very small dimensions. Its length ranges from 3 to 6 cm; weight 2 , 5 —3 g; gland is slightly higher than in adults, but weakly fixed to the posterior abdominal wall and relatively mobile. By age 3, its weight reaches 20 grams, by age 10-12 – 30 grams. The appearance is characteristic of adults; iron takes 5-6 years to age. With age, the relationship between the exocrine and endocrine parts of the pancreas changes towards a decrease in the number of islets.
Functions of the pancreas
The cells of the exocrine pancreas are filled with secretory granules containing precursors of digestive enzymes (mainly trypsinogen, chymotrypsinogen, pancreatic lipase and amylase), which are secreted into the acinus lumen. These are the so-called zymogen granules containing inactive precursors of enzymes. The formation of enzymes in an inactive form is an important factor preventing enzymatic damage to the pancreas, often observed in pancreatitis. The pancreas is the main source of enzymes for the digestion of fats and proteins. The main pancreatic secretion of ductal cells contains bicarbonate ions and is involved in the neutralization of the acidic gastric chyme. The hormonal regulation of the exocrine function of the pancreas is provided by gastrin, cholecystokinin and secretin, hormones produced by the cells of the stomach and duodenum in response to stretching and pancreatic juice secretion.
The pancreas secretes two major proteolytic enzymes: trypsinogen and chymotrypsinogen. These are zymogens – inactive forms of trypsin and chymotrypsin. When released into the intestine, they are exposed to enterokinase, which is present in the parietal mucus, which activates the trypsinogen, converting it into trypsin. Free trypsin then cleaves the rest of the trypsinogen and chymotrypsinogen to their active forms. The secret of the pancreas accumulates in the interlobular ducts, which merge with the main excretory duct, opening into the duodenum. Damage to the pancreas is a serious hazard. Puncture of the pancreas requires special care when performing. Numerous groups of cells that do not have excretory ducts are interspersed between the lobules. islets of Langerhans. Islet cells secrete hormones insulin and glucagon.The islets of Langerhans function as endocrine glands (endocrine glands), releasing glucagon and insulin directly into the bloodstream – hormones that regulate carbohydrate metabolism. These hormones have the opposite effect: glucagon increases, and insulin lowers blood sugar levels.