The pancreas is an organ of exo-and endocrine secretion, whose work is characterized by influence on the processes of enzymatic digestion and carbohydrate metabolism. It is located in the retroperitoneal space at the level of the first lumbar vertebrae in the conventional bed of loose fatty tissue.
Topographically it is surrounded by:
- stomach in front and above;
- with the spleen and its vessels on the left;
- with the duodenal gut on the right and below;
- by the main vessels and fatty tissue behind.
The pancreas consists of the head, body and tail. Its length ranges from 15-20 cm, and weighs about 70 g. It occupies a transverse position relative to the axis of the human body.
Structural and functional characteristics of the pancreas
Has a lobate-ductal structure. Lobules consist of specialized cells - pancreatocytes. They synthesize enzymes into the lumen of the lobule. Then there is the formation of pancreatic juice, moving along the ducts into the duodenum. Structural and functional characteristics of the pancreatic duct system consists of the following ducts:
- intra-lobular;
- interlobular;
- main excretory duct( Virsungov).
Virsungov duct with bile duct opens into the large papilla( feces) of the duodenum. There is a special sphincter( Oddi), which regulates the intake of pancreatic juice and bile.
Pancreatocytes forming a lobule characterize the exocrine function of the pancreas. This exocrine activity is divided into:
- ekbolicheskoy( production of amino acids);
- hydrokinetic( production of water, hydrocarbonates, chlorides and microelements).
All these substances form pancreatic juice. For a day it is formed up to 2 liters. Characteristics of pancreatic juice enzymes are individual and specific. Amylases break down carbohydrates, trypsin and chymotrypsin - proteins, nucleases - nucleic acids, lipases - fats. Due to the hydrokinetic components, the optimal medium necessary for activation and normal functioning of the enzymes is maintained.
Endocrine functioning of the pancreas is carried out by special cells located in the tail. They are surrounded by a large network of vessels to immediately produce hormones in the blood to regulate tissue metabolism. These cells are grouped in the so-called islets of Langerhans. The following hormones are produced:
- ß - cells( insulin synthesis);
- a - cells( production of glucagon and lipocaine, kallikrein);
- D - cells( production of gastrin, somatostatin, pancreatic polypeptide).
Insulin and glucagon are pancreatic hormone antagonists that affect the characteristics of carbohydrate metabolism. The first reduces the level of glucose in the blood, the second, on the contrary, increases. Lipocaine regulates fat metabolism. Kallikrein has an effect on the vascular wall, expanding the vessels. Characterization of somatostatin - decreased production of pancreatic juice. Gastrin affects the secretion of hydrochloric acid in the stomach, increasing it.