Hormones of the pancreas and their functions
human body is a complex system of biochemicalProcesses, which are closely interrelated, and proceed due to hormones - special biologically active substances, produced by specific organs, namely glands intraSecretory secretions.
Structure and function of the
One of the important organs of the digestive system is the pancreas, which is considered the largest gland in the human body. It is a small elongated organ of grayish-pink color, located in the retroperitoneal space on the back wall of the peritoneal cavity, and closely adjoins the duodenum. In its structure, it differs from other organs, and has a proper body, head and tail. The pancreas is the organ of mixed secretion and produces important hormones.
The pancreas length is 13-22 cm in length in an adult human and weighs approximately 65-80 g. The pancreas in its structure resembles an alveolar-tubular structure. In addition, the structure of the gland includes nerves, nerve ganglia, vessels, lamellar substances, as well as complex excretory ducts. The pancreas has two main parts: endocrine and exocrine, which perform certain functions.
Exocrine part
The exocrine part is a complex system of excretory ducts that have an exit directly into the duodenum. The exocrine part accounts for almost 96% of the total body weight, and its main function is the production of digestive juice containing the enzymes necessary for food processing.
Endocrine part of
Endocrine part consists of islets of Langerhans or pancreatic islets. They are distinguished by the presence of cells that differ in their morphological and physico-chemical properties.
The islets of Langerhans are an accumulation of endocrine cells in which the synthesis of important hormones necessary for the regulation of carbohydrate, protein and fat metabolism occurs. The main hormones produced by the pancreas are insulin, glucagon and c-peptide. In addition, endocrine cells produce somatostatin, gastrin, tiroliberin.
Conditionally endocrine cells can be divided into four main types:
- A - alpha cells, which constitute only 15-20% of the total number of gland cells, and synthesize glucagon;
- B - beta cells that make up the bulk of pancreatic cells - about 65-80%.They produce the necessary hormone insulin. Beta-cells with the age of the patient are gradually destroyed, so that their number inevitably decreases.
- D - delta cells make up a small part of the total number of organ cells - only 5-10%.Delta cells synthesize somatostatin.
- F - PP cells are present in the pancreas in small amounts and produce a pancreatic polypeptide.
Another important hormone that is produced in the gland is the c-peptide that participates in the carbohydrate metabolism, and which is considered to be a fragment of the insulin molecule. Violation of the synthesis of hormones often leads to the development of various serious diseases, including diabetes.
The pancreas performs several functions, the main ones of which are:
- digestive juice production;
- splitting of consumed food;
- regulation of blood glucose levels with glucagon and insulin.
The main functions of the hormones
Pancreatic hormones have distinctive characteristics and perform certain functions unique to them in the human body.
Insulin
Insulin is a polypeptide hormone that produces the pancreas. Its structure is composed of two chains of amino acids, which are connected by chemical bridges. Insulin, characterized by its structure, is present in all living things, even in amoeba. Almost identical with the human hormone, the composition of insulin is found in pigs and rabbits. The pancreas produces insulin from proinsulin by separating the c-peptide.
The main role of insulin is to regulate the level of glucose in the blood by cleavage and penetration into the organs and tissues of the body. Insulin promotes the absorption of glucose by the fat and muscle tissues of the body, and also promotes the conversion of glucose into glycogen, which is deposited in the muscles and liver. It is used by the body in case of glucose deficiency with increased physical exertion.
Insulin prevents the formation of glucose in the liver, that is, prevents the occurrence of glycogenolysis and glycoeogenesis. In addition, it reduces the possibility of fat splitting, and the formation of ketone bodies. An important role is played by insulin in the lives of athletes, as it stimulates the consumption of nucleotides and amino acids for the synthesis of DNA and RNA, as well as nucleic acids.
Glucagon
Glucagon is a polypeptide whose structure is only one chain of amino acids. The functions of glucagon are directly opposite from those of insulin. The role of glucagon is the ability of the body to break down lipids in fatty tissues. He is also responsible for increasing the amount of glucose in the blood that is formed in the liver.
Glucagon as well as insulin helps maintain normal blood sugar levels in humans, by providing adequate protection.
However, it is proved that in addition to these two hormones, other hormones and biologically active compounds are involved in this normalization process. They can include somatotropin, cortisol and adrenaline. Glucagon plays an important role in the human body. It increases renal blood flow, normalizes the level of cholesterol in the blood, and also increases the ability of the liver to self-regeneration. Glucagon promotes the rapid removal of sodium from the body, which reduces the likelihood of edema.
Incorrect regulation of glucagon promotes the development of such a disease as a malignant tumor of the pancreas or glucagon. Fortunately for patients, this disease is quite rare.
Somatostatin
Somatostatin is also considered a polypeptide hormone, the role of which is to inhibit or stop the synthesis of various hormones: thyroid-stimulating hormones, insulin, somatotropin, glucagon and other equally important hormones. Disturbance of somatostatin production often leads to the development of many serious pathologies associated with the process of digestion, since it is somatostatin that suppresses the secretion of digestive enzymes and bile.
Somatostatin is used in pharmacology in the manufacture of drugs for the treatment of many diseases associated with excessive production of growth hormone, namely acromegaly. This disease is characterized by a pathological increase in individual parts of the body, bones of the skull, limbs, feet.
It is now proved that pancreatic hormones produced in the human body play a crucial role in the development of the body, its formation and life activity.
