Synonyms
Medical: Pancreas English: pancreas
Anatomy
The pancreas is a gland weighing about 80g, 14 to 18 cm long and is located in the upper abdomen between the small intestine and the spleen. It is not actually located inside the abdominal cavity, but rather very far back, directly in front of the spine. Unlike many other organs of the gastrointestinal tract, it is not covered with the skin lining the abdominal cavity (peritoneum). Due to its appearance, the entire gland is divided into head (caput), body (corpus) and tail (cauda).
Pancreas position
The pancreas lies crosswise in the upper abdomen. During embryonic development it is completely covered by the peritoneum (intraperitoneal position), but changes its position during growth and can be found behind the peritoneum after birth (secondary retroperitoneal position). The pancreas therefore lies in the so-called retroperitoneal space and is bordered on the right side by the liver, on the left side by the spleen and anteriorly (lat.
ventral) by the stomach. In addition, there are close neighbourhood relationships to the aorta, the inferior vena cava and the duodenum. The C-shaped loop of the duodenum frames the head of the pancreas (Caput pancreatis).
The remaining sections of the gland also have close anatomical relationships with specific structures of the abdominal cavity. Thus, the large body of the pancreas (corpus) runs through the upper abdomen, crossing the spinal column in the area of the second lumbar vertebra. The pancreas tail moves into the left upper abdomen to such an extent that it comes into proximity with the left kidney and spleen. A small sac of the pancreas (Processus uncinatus) is located between the head and the body and is in a positional relationship to the most important vessels for supplying the intestinal tract (Arteria et Vena mesenterica superior).
Function of the pancreas
The main task of the pancreas is the production of digestive enzymes and digestive hormones. The hormones of the pancreas are released directly into the blood (so-called endocrine secretion). Enzymes are proteins that are actively able to break down food and prepare it for absorption through the mucous membrane of the intestine.
The hormones of the pancreas are released directly into the blood (so-called endocrine secretion). Enzymes are proteins that are actively able to break down food and prepare it for absorption through the intestinal mucosa. The enzymes reach their site of action in the small intestine via a special duct running lengthwise through the entire gland, the pancreatic duct (lat.
ductus pancreaticus). Since the enzymes formed serve to break down food components, they are very aggressive substances. The pancreas therefore has effective protective mechanisms against self-digestion: Protein-splitting enzymes (peptidases) such as trypsin and chymotrypsin are formed in the form of inactive precursors.
The conversion into “biologically active scissors” takes place in the small intestine (by means of an enzyme called enterokinase, which cuts off small fragments from the trypsin precursor trypsinogen, thus producing functional trypsin. This is also the activator for the other hormones. In addition, the pancreas produces starch-splitting enzymes (amylases), fat-splitting enzymes (lipases) and nucleic acid-splitting enzymes (ribonucleinases; these are used to digest nuclear components).
However, all the enzymes mentioned only function optimally if the acidity in their environment is not too high (= pH 8). As the food comes from the stomach which is predigested by hydrochloric acid, the stomach acid must first be neutralised. To do this, the enzymes are released into the small intestine with 1-2 litres of an aqueous, bicarbonate-rich (=neutralising) fluid, the pancreas.
The pancreas is responsible for this so-called exocrine function. Exocrine function is the production of enzymes for the digestive tract. The entire tissue of the pancreas – like many other glands, e.g. the thyroid gland – is divided into lobes separated by connective tissue.
Within the connective tissue lines are the vessels, nerves and lymphatic vessels that supply the pancreas with blood. Specialised cells, the glandular end pieces (azini), are responsible for enzyme production. These secrete the enzymes into ducts running inside the pancreas, which ultimately all lead to a large common duct, the ductus pancreaticus (see above).
The special feature of these many small excretory ducts is that they also have another function: They are responsible for the neutralization of gastric acid through the formation of pancreas. In contrast, the hormone-producing (endocrine) part of the pancreas is only small. It is also known as an islet organ: The arrangement of these cells in groups, which are diffusely scattered throughout the gland, is reminiscent of islets under the microscope.
The most common are the approximately 1 million islets in the posterior part (the so-called tail). The most important (and with a share of over 80% also the most produced) hormone is insulin. Its task is to enable the absorption of sugar (glucose; breakdown product of carbohydrate-rich food) into the body cells and thus lower the blood sugar level.
The absence or deficiency of this hormone leads to diabetes (diabetes mellitus): the blood becomes saturated with unused sugar. The insulin producing cells are called B cells. A-cells, on the other hand, produce a hormone that works in the opposite direction, glucagon.
If the last meal is a long time ago, it ensures that sugar is released from the liver‘s reserves. This ensures that the internal organs are always sufficiently supplied (especially by the brain, which is compulsorily dependent on sugar and cannot fall back on other food components). Only a very small proportion of hormone production is accounted for by those messenger substances that are produced specifically for the regulation of the pancreas itself: The D-cell hormone somatostatin, which inhibits insulin and glucagon production, and the pancreatic polypeptide (PP), which inhibits the exocrine part of the pancreas that produces digestive enzymes.
The regulation of enzyme release is also regulated by hormones produced specifically for this purpose and the autonomic nervous system. (This part of the nervous system is also known as the autonomous nervous system because it controls the processes that take place unconsciously in the body. Together the part of the autonomous nervous system called the parasympathetic nervous system and the hormone cholecystokinin (CCK) stimulate enzyme production.
As a hormone, secretin also stimulates the release (=secretion) of water and bicarbonate through the cells of the pancreatic ducts. Both secretin and cholecystokinin are produced by specialized cells, the so-called S-cells and I-cells. These are interspersed between the surface cells in the entire gastrointestinal tract (especially in the small intestine) and are collectively known as enteroendocrine cells (=gr.
enteron = intestine, corresponding to the main active organ of these hormones). Through this complex interaction of different regulatory mechanisms, the entire digestion and sugar balance of the body is regulated by self-controlling mechanisms. This principle can be found in various parts of the body, such as the thyroid gland.
A number of values detectable in blood and/or urine can be used to assess pancreatic function. For the treating physician, knowledge of the normal values is therefore all the more essential. Pancreatic amylase (alpha-amylase), an enzyme for carbohydrate digestion, can be detected in blood serum, 24-hour urine and even in the fluid of ascites.
The normal values of a woman are about 120 U per liter (U/L) in blood serum and about 600 U/L in urine. The same normal values apply to men. Bilirubin (or urobilinogen) can also be detected in blood serum, plasma and urine.
The norm for adults is between 0.1 and 1.2 milligrams per deciliter (mg/dl) in blood serum. The urine should normally not contain any bilirubin components. An elevated bilirubin level indicates the presence of a cyst with narrowing of the outflow pathways of the gallbladder in relation to pancreatic diseases.
The number of white blood cells (leukocytes) in whole blood or urine can also be used as a parameter. The normal value of a healthy adult in whole blood is between a minimum of 4000 and a maximum of 10,000 leukocytes per microlitre. In a healthy person, no white blood cells should be detectable in the urine, because the elimination of leukocytes with the urine always indicates a pathological process.
In most cases, an increased leukocyte count results from an inflammation within the organism. In addition, a decrease in the calcium concentration in blood serum and/or urine indicates an inflammation of the pancreas (standard value: 8.8- 10.4 mg/dl). The enzyme chymotrypsin can be detected in the stool, in healthy individuals the normal value is approximately 6 U/g, a decrease can be an indication of a functional impairment of the pancreas.
A decrease in the pancreatic lipase concentration also indicates a reduction in function (standard value: 190 U/L). and Bilirubin (or urobilinogen) can also be detected in blood serum, plasma and urine. The norm for adults in blood serum is between 0.1 and 1.2 milligrams per deciliter (mg/dl).
The urine should normally not contain any bilirubin components. An elevated bilirubin level indicates the presence of a cyst with narrowing of the outflow pathways of the gallbladder in relation to pancreatic diseases. The number of white blood cells (leukocytes) in whole blood or urine can also be used as a parameter.
The normal value of a healthy adult in whole blood is between a minimum of 4000 and a maximum of 10,000 leukocytes per microlitre. In a healthy person, no white blood cells should be detectable in the urine, because the elimination of leukocytes with the urine always indicates a pathological process. In most cases, an increased leukocyte count results from an inflammation within the organism.
In addition, a decrease in the calcium concentration in blood serum and/or urine indicates an inflammation of the pancreas (standard value: 8.8- 10.4 mg/dl). The enzyme chymotrypsin can be detected in the stool, in healthy individuals the normal value is approximately 6 U/g, a decrease can be an indication of a functional impairment of the pancreas. A decrease in the pancreatic lipase concentration also indicates a reduction in function (standard value: 190 U/L).
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