Anatomy
The pancreas is a gland located in the upper abdomen between the small intestine and the spleen. It weighs about 80 g and is 14 to 18 cm long. It is not really within the abdominal cavity, but very far back in front of the spine. Therefore, it is not covered by other organs of the gastrointestinal tract lining the abdominal cavity.
The gland is divided in the head (caput), body (corpus) and tail (cauda).
Function
The main task of the pancreas is the production of digestive enzymes and digestive hormones. The hormones in the pancreas are released directly into the blood (the so-called endocrine secretion). These enzymes include proteins that can actively disassemble food.
Localization of the pancreas in the body
The gland runs along the pancreatic duct and the enzymes reach their target site in the small intestine. These enzymes are very aggressive substances as they are formed by the fragmentation of food components. The pancreas thus has effective safeguards against self-digestion: protein-cleaving enzymes (peptidases) such as trypsin and chymotrypsin are inactive precursors. The conversion to "biologically active shearing" occurs in the small intestine (it is performed by an enzyme called enterokinase). This also activates other hormones. The pancreas also contains starch-splitting enzymes (amylases), fat-splitting enzymes (lipases) and nucleic acid-cleaving enzymes (ribonucleases, which are used for the digestion of nuclear components). These enzymes work best in low acidity environments (pH = 8). In the small intestine, they are modified in 1-2 liters of an aqueous bicarbonate fluid (= neutralizer). The pancreas is mainly responsible for this so-called exocrine function. The exocrine function is defined as the production of enzymes for the digestive tract.
Similarly to many other glands, such as the thyroid gland, the pancreas is divided into lobes, which are separated by connective tissue. The connective tissue paths within the pancreas are supplied with blood vessels, nerves and lymphatic vessels. The enzyme production is carried out by specialized cells (acini).
The special feature of the many small excretory vessels in the pancreas is that they also have another function: they are responsible for the neutralization of the stomach acid. This is facilitated by the production of pancreatic fluid.
On the other hand, the pancreas only plays a small role in hormone production. It is also known as an island institution: these cells are arranged in groups and scattered throughout the gland. There are roughly 1 million islands in the rear part (the so-called tail). The hormone insulin is the most important (with a share of over 80%). Its task is the inclusion of sugar. The absence or deficiency of this hormone leads to diabetes (diabetes mellitus): the blood is not saturated with recycled sugar.
The insulin-producing cells are called B-cells. A cells, on the other hand, produce a hormone called glucagon. This hormone ensures the supply of sugar from the liver. So the internal organs always receive a sufficient supply (especially the brain, which is dependent on sugar and not necessarily other food components).
Only a very small proportion of this hormone is spent on those mediators responsible for the regulation of the pancreas. The hormones that have an inhibitory effect on insulin and glucagon production are those produced by the D cells: somatostatin as well as the digestive enzyme-producing (exocrine) pancreatic polypeptide (PP).
GH and the anatomy of the autonomic nervous system are specifically responsible for the regulation of enzyme release (the autonomous nervous system is an independent nervous system also known to control the unconscious processes that run in the body). The parasympathetic nervous system, the autonomic nervous system and the hormone cholecystokinin (CCK) stimulate the enzyme production. Secretin also stimulates the release of water and bicarbonate by the cells of the pancreatic ducts.
Both secretin and cholecystokinin are formed by specialized cells - the so-called S cells and I cells. These are interspersed among the epithelial cells throughout the gastrointestinal tract (particularly in the small intestine) and are collectively referred to as enteroendocrine cells (according to the main producer of these hormones).
The entire digestion process and the sugar balance of the body are regulated by self-controlling mechanisms through this complex interplay of various regulations mechanisms. This principle applies to various parts of the body, including the thyroid gland.
