Introduction
The pancreas lies behind the peritoneum (retroperitoneal) in the upper abdomen. The pancreas has two parts, a so-called exocrine (= outward-facing) and an endocrine (= inward-facing). The exocrine part is the pancreas, i.e. a digestive juice that is released into the duodenum. The endocrine part produces the hormones insulin and glucagon and releases them into the blood. They are important for the regulation of the blood sugar level.
Digestive function
The pancreas is built up in lobules. The exocrine part of the pancreas, which forms the main mass of the organ, is a purely serous gland, which means that it produces a very fluid secretion. In this part, about 1.5 l of pancreatic secretion is produced daily.
This is an enzyme-rich, basic digestive juice which is released into the duodenum. Secretion is regulated by digestive processes, with the rate of secretion increasing sharply after ingestion of food. The enzymes for fat splitting (lipases), protein (proteases) and carbohydrate digestion contained in the pancreas make an important contribution to the digestion of food and ensure that nutrients can be efficiently absorbed from the intestine into the blood.
In addition to the main portion of water, pancreas consists of over 20 different proteins; these are inactive precursors of digestive enzymes (zymogens) and active digestive enzymes. Particularly aggressive proteases, such as trypsin or chymotrypsin, are secreted as inactive precursors to protect the pancreas from self-digestion and are only activated in the duodenum. Further proteases (e.g. α-amylase), lipase and enzymes for nucleic acid digestion are directly released into the pancreas as active enzymes.
Protective and regulatory proteins are another important component of pancreatic juice. In addition to digestive enzymes, pancreatic juice consists of bicarbonate, which serves to neutralize the acidic stomach contents and leads to a slightly alkaline pH value of 8.1 in the duodenum. The increase of the bicarbonate concentration in the small intestine is important because on the one hand it facilitates the micelle formation of fats and on the other hand, various digestive enzymes are inactive in the acidic environment and only work at alkaline values.
Various protective mechanisms prevent the pancreas from digesting and thus destroying itself by the pancreatic juice produced: some particularly dangerous proteases are secreted as inactive zymogens and are only activated in the duodenum. In addition, a number of protective enzyme inhibitors are released simultaneously with the digestive enzymes and special proteases break down enzymes that have been activated too early. Various protective mechanisms prevent the pancreas from digesting and thus destroying itself by the pancreatic juice produced: some particularly dangerous proteases are secreted as inactive zymogens and are only activated in the duodenum. In addition, a number of protective enzyme inhibitors are released simultaneously with the digestive enzymes and special proteases break down enzymes that have been activated too early.
