The human endocrine apparatus briefly. The system of regulation of the body's work through hormones or the human endocrine system: structure and functions, diseases of the glands and their treatment

Endocrine system- a system for regulating the activity of internal organs by means of hormones secreted by endocrine cells directly into the blood, or diffusing through the intercellular space into neighboring cells.

The endocrine system is divided into the glandular endocrine system (or glandular apparatus), in which the endocrine cells are brought together to form the endocrine gland, and the diffuse endocrine system. The endocrine gland produces glandular hormones, which include all steroid hormones, thyroid hormones, and many peptide hormones. The diffuse endocrine system is represented by endocrine cells scattered throughout the body that produce hormones called aglandular - (with the exception of calcitriol) peptides. Almost every tissue in the body contains endocrine cells.

Endocrine system. Main endocrine glands. (on the left - a man, on the right - a woman): 1. Epiphysis (refer to the diffuse endocrine system) 2. Pituitary gland 3. Thyroid gland 4. Thymus 5. Adrenal gland 6. Pancreas 7. Ovary 8. Testicle

Functions of the endocrine system

  • It takes part in the humoral (chemical) regulation of body functions and coordinates the activity of all organs and systems.
  • It ensures the preservation of the body's homeostasis under changing environmental conditions.
  • Together with the nervous and immune systems, it regulates
    • growth,
    • body development,
    • its sexual differentiation and reproductive function;
    • takes part in the processes of formation, use and conservation of energy.
  • Together with the nervous system, hormones are involved in providing
    • emotional
    • mental activity of a person.

glandular endocrine system

The glandular endocrine system is represented by separate glands with concentrated endocrine cells. Endocrine glands (endocrine glands) are organs that produce specific substances and secrete them directly into the blood or lymph. These substances are hormones - chemical regulators necessary for life. Endocrine glands can be both independent organs and derivatives of epithelial (border) tissues. The endocrine glands include the following glands:

Thyroid

The thyroid gland, whose weight ranges from 20 to 30 g, is located in the front of the neck and consists of two lobes and an isthmus - it is located at the level of the ΙΙ-ΙV cartilage of the windpipe and connects both lobes. On the back surface of the two lobes, there are four parathyroid glands in pairs. Outside, the thyroid gland is covered with neck muscles located below the hyoid bone; with its fascial sac, the gland is firmly connected to the trachea and larynx, so it moves following the movements of these organs. The gland consists of vesicles of an oval or round shape, which are filled with a protein iodine-containing substance such as a colloid; loose connective tissue is located between the vesicles. The vesicle colloid is produced by the epithelium and contains the hormones produced by the thyroid gland - thyroxine (T4) and triiodothyronine (T3). These hormones regulate the metabolic rate, promote the uptake of glucose by the cells of the body and optimize the breakdown of fats into acids and glycerol. Another hormone secreted by the thyroid gland is calcitonin (polypeptide by chemical nature), it regulates the content of calcium and phosphates in the body. The action of this hormone is directly opposite to parathyroidin, which is produced by the parathyroid gland and increases the level of calcium in the blood, increases its influx from the bones and intestines. From this point, the action of parathyroidin resembles that of vitamin D.

parathyroid glands

The parathyroid gland regulates calcium levels in the body within narrow limits so that the nervous and motor systems function normally. When the level of calcium in the blood falls below a certain level, the calcium-sensitive parathyroid glands become activated and secrete the hormone into the blood. Parathyroid hormone stimulates osteoclasts to release calcium from bone tissue into the blood.

thymus

The thymus produces soluble thymic (or thymic) hormones - thymopoietins, which regulate the processes of growth, maturation and differentiation of T cells and the functional activity of mature cells. With age, the thymus degrades, being replaced by a connective tissue formation.

Pancreas

The pancreas is a large (12-30 cm long) secretory organ of double action (secretes pancreatic juice into the lumen of the duodenum and hormones directly into the bloodstream), located in the upper part of the abdominal cavity, between the spleen and duodenum.

The endocrine pancreas is represented by the islets of Langerhans located in the tail of the pancreas. In humans, islets are represented by various types of cells that produce several polypeptide hormones:

  • alpha cells - secrete glucagon (a regulator of carbohydrate metabolism, a direct antagonist of insulin);
  • beta cells - secrete insulin (a regulator of carbohydrate metabolism, lowers blood glucose levels);
  • delta cells - secrete somatostatin (inhibits the secretion of many glands);
  • PP cells - secrete pancreatic polypeptide (suppresses pancreatic secretion and stimulates gastric juice secretion);
  • Epsilon cells - secrete ghrelin ("hunger hormone" - stimulates appetite).

adrenal glands

At the upper poles of both kidneys are small triangular-shaped glands - the adrenal glands. They consist of an outer cortical layer (80-90% of the mass of the entire gland) and an inner medulla, the cells of which lie in groups and are entwined with wide venous sinuses. The hormonal activity of both parts of the adrenal glands is different. The adrenal cortex produces mineralocorticoids and glycocorticoids, which have a steroidal structure. Mineralocorticoids (the most important of them is amide oox) regulate ion exchange in cells and maintain their electrolytic balance; glycocorticoids (eg, cortisol) stimulate protein breakdown and carbohydrate synthesis. The medulla produces adrenaline, a hormone from the catecholamine group, which maintains sympathetic tone. Adrenaline is often referred to as the fight-or-flight hormone, as its secretion rises sharply only in moments of danger. An increase in the level of adrenaline in the blood entails corresponding physiological changes - the heartbeat quickens, blood vessels constrict, muscles tighten, pupils dilate. The cortex also produces small amounts of male sex hormones (androgens). If disorders occur in the body and androgens begin to flow in an extraordinary amount, the signs of the opposite sex increase in girls. The adrenal cortex and medulla differ not only in different hormones. The work of the adrenal cortex is activated by the central, and the medulla - by the peripheral nervous system.

DANIEL and human sexual activity would be impossible without the work of the gonads, or sex glands, which include the male testicles and female ovaries. In young children, sex hormones are produced in small quantities, but as the body grows older, at a certain point, a rapid increase in the level of sex hormones occurs, and then male hormones (androgens) and female hormones (estrogens) cause a person to develop secondary sexual characteristics.

Hypothalamic-pituitary system

Almost every tissue in the body contains endocrine cells.

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    Subtitles

    I'm at Stanford Medical School with Neil Gesundheit, one of the faculty. Hello. What do we have today? Today we will talk about endocrinology, the science of hormones. The word "hormone" comes from the Greek word meaning "stimulus". Hormones are chemical signals that are produced in certain organs and act on other organs, stimulating and controlling their activity. That is, they communicate between organs. Yes exactly. These are means of communication. Here's the right word. This is one of the types of communication in the body. For example, nerves lead to muscles. To contract a muscle, the brain sends a signal along the nerve that goes to the muscle, and it contracts. And hormones are more like Wi-Fi. No wires. Hormones are produced and carried by the bloodstream like radio waves. In this way, they act on widely located organs, without having a direct physical connection with them. Are hormones proteins or something else? What are these substances anyway? According to their chemical nature, they can be divided into two types. These are small molecules, usually derivatives of amino acids. Their molecular weight ranges from 300 to 500 daltons. And there are large proteins with hundreds of amino acids. It's clear. That is, these are any signal molecules. Yes, they are all hormones. And they can be divided into three categories. There are endocrine hormones that are released into the bloodstream and work remotely. I'll give examples in just a minute. There are also paracrine hormones that have a local effect. They act at a short distance from the place where they were synthesized. And hormones of the third, rare category - autocrine hormones. They are produced by a cell and act on the same cell or a neighboring one, that is, at a very short distance. It's clear. I would like to ask. About endocrine hormones. I know they are released somewhere in the body and bind to receptors, then they act. Paracrine hormones have a local effect. Is the action weaker? Usually, paracrine hormones enter the bloodstream, but their receptors are located very close. This arrangement of receptors determines the local nature of the action of paracrine hormones. It's the same with autocrine hormones: their receptors are located right on this cell. I have a stupid question: there are endocrinologists, but where are the paracrinologists? Good question, but they don't. Paracrine regulation was discovered later and studied within the framework of endocrinology. It's clear. Endocrinology studies all hormones, not just endocrine ones. Exactly. Well said. This figure shows the main endocrine glands, which we will talk about a lot. The first is in the head, or rather in the region of the base of the brain. This is the pituitary gland. Here he is. This is the main endocrine gland that controls the activity of other glands. For example, one of the pituitary hormones is thyroid-stimulating hormone, TSH. It is secreted by the pituitary gland into the bloodstream and acts on the thyroid gland, where there are many receptors for it, forcing the production of thyroid hormones: thyroxine (T4) and triiodothyronine (T3). These are the main thyroid hormones. What are they doing? Regulate metabolism, appetite, heat production, even muscle function. They have many different effects. Do they stimulate the overall metabolism? Exactly. These hormones speed up the metabolism. High heart rate, fast metabolism, weight loss are signs of excess of these hormones. And if there are few of them, then the picture will be completely opposite. This is a good example of the fact that hormones should be exactly as much as needed. But back to the pituitary gland. He is in charge, sending orders to everyone. Exactly. He has feedback to stop the production of TSH in time. Like a device, it monitors the level of hormones. When there are enough of them, it reduces the production of TSH. If there are few of them, it increases the production of TSH, stimulating the thyroid gland. Interesting. What else? Well, signals to the rest of the glands. In addition to thyroid-stimulating hormone, the pituitary secretes adrenocorticotropic hormone, ACTH, affecting the adrenal cortex. The adrenal gland is located at the pole of the kidney. The outer layer of the adrenal gland is the cortex, which is stimulated by ACTH. It does not apply to the kidney, they are located separately. Yes. They are related to the kidney only by a very rich blood supply due to their proximity. Well, the kidney gave the gland its name. Well, it's obvious. Yes. But the functions of the kidney and adrenal gland are different. It's clear. What is their function? They produce hormones such as cortisol, which regulate glucose metabolism, blood pressure and well-being. As well as mineralocorticoids, such as aldosterone, which regulates the water-salt balance. In addition, it releases important androgens. These are the three main hormones of the adrenal cortex. ACTH controls the production of cortisol and androgens. Let's talk about mineralocorticoids separately. What about the rest of the glands? Yes Yes. The pituitary gland also secretes luteinizing hormone and follicle-stimulating hormone, abbreviated as LH and FSH. Gotta write it down. They affect the testicles in men and the ovaries in women, respectively, stimulating the production of germ cells, as well as the production of steroid hormones: testosterone in men and estradiol in women. Is there anything else? There are two more hormones from the anterior pituitary gland. It is a growth hormone that controls the growth of long bones. The pituitary gland is very important. Yes very. Is STG abbreviated? Yes. Somatotropic hormone, aka growth hormone. And then there is prolactin, necessary for breastfeeding a newborn baby. What about insulin? A hormone, but not from the pituitary gland, but at a lower level. Like the thyroid gland, the pancreas secretes its own hormones. In the tissue of the gland there are islets of Langerhans, which produce endocrine hormones: insulin and glucagon. Without insulin, diabetes develops. Without insulin, tissues cannot take up glucose from the bloodstream. In the absence of insulin, symptoms of diabetes occur. In the figure, the pancreas and adrenal glands are located close to each other. Why? Tooting. There is a good venous outflow, which allows vital hormones to enter the blood faster. Interesting. I think that's enough for now. In the next video, we will continue this topic. OK. And we will talk about the regulation of hormone levels and pathologies. Good. Thanks a lot. And thank you.

Functions of the endocrine system

  • It takes part in the humoral (chemical) regulation of body functions and coordinates the activity of all organs and systems.
  • It ensures the preservation of the body's homeostasis under changing environmental conditions.
  • Together with the nervous and immune systems, it regulates:
    • growth;
    • body development;
    • its sexual differentiation and reproductive function;
    • takes part in the processes of formation, use and conservation of energy.
  • Together with the nervous system, hormones are involved in providing:
    • emotional reactions;
    • mental activity of a person.

glandular endocrine system

In the hypothalamus, the hypothalamic proper (vasopressin or antidiuretic hormone, oxytocin, neurotensin) and biologically active substances that inhibit or enhance the secretory function of the pituitary gland (somatostatin, thyroliberin or thyrotropin-releasing hormone, luliberin or gonadoliberin or gonadotropin-releasing hormone, corticoliberin or corticotropin-releasing hormone) are secreted. hormone and somatoliberin or somatotropin-releasing hormone). One of the most important glands of the body is the pituitary gland, which controls the work of most endocrine glands. The pituitary gland is small, weighing less than one gram, but very important for the life of iron. It is located in a depression at the base of the skull, connected to the hypothalamic region of the brain by a stalk and consists of three lobes - anterior (glandular, or adenohypophysis), middle or intermediate (it is less developed than others) and posterior (neurohypophysis). In terms of the importance of the functions performed in the body, the pituitary gland can be compared with the role of the conductor of an orchestra, which shows when this or that instrument should come into play. Hypothalamic hormones (vasopressin, oxytocin, neurotensin) flow down the pituitary stalk into the posterior lobe of the pituitary gland, where they are deposited and from where, if necessary, are released into the bloodstream. The hypophysiotropic hormones of the hypothalamus, being released into the portal system of the pituitary gland, reach the cells of the anterior pituitary gland, directly affecting their secretory activity, inhibiting or stimulating the secretion of tropic pituitary hormones, which, in turn, stimulate the work of the peripheral endocrine glands.

  • VIPoma;
  • Carcinoid;
  • Neurotensin;

Vipom's syndrome

Main article: VIPoma

VIPoma (Werner-Morrison syndrome, pancreatic cholera, watery diarrhea-hypokalemia-achlorhydria syndrome) is characterized by the presence of watery diarrhea and hypokalemia as a result of islet cell hyperplasia or a tumor, often malignant, originating from pancreatic islet cells (usually the body and tail), which secrete a vasoactive intestinal polypeptide (VIP). In rare cases, VIPoma can occur in ganglioneuroblastomas, which are localized in the retroperitoneal space, lungs, liver, small intestine and adrenal glands, occur in childhood and are usually benign. The size of pancreatic VIPomas is 1...6 cm. In 60% of cases of malignant neoplasms, there are metastases at the time of diagnosis. The incidence of VIPoma is very low (1 case per year per 10 million people) or 2% of all endocrine tumors of the gastrointestinal tract. In half of the cases, the tumor is malignant. The prognosis is often unfavorable.

gastrinoma

Glucagonoma

Glucagonoma is a tumor, often malignant, originating from the alpha cells of the pancreatic islets. It is characterized by migratory erosive dermatosis, angular apapacheilitis, stomatitis, glossitis, hyperglycemia, normochromic anemia. It grows slowly, metastasizes to the liver. It occurs in 1 case in 20 million between the ages of 48 and 70, more often in women.

Carcinoid is a malignant tumor usually originating in the gastrointestinal tract that produces several hormone-like substances

Neurotensinoma

PPoma

Distinguish:

  • somatostatin from the delta cells of the pancreas and
  • apudoma secreting somatostatin - duodenal tumor.

The diagnosis is based on the clinic and an increase in the level of somatostatin in the blood. Treatment is surgical, chemotherapy and symptomatic. The prognosis depends on the timeliness of treatment.

The endocrine system occupies an important place among the regulatory systems of the body. The endocrine system carries out its regulatory functions with the help of hormones produced by it. Hormones through the intercellular substance penetrate into each organ and tissue or are carried throughout the body with blood. Part of the endocrine cells forms endocrine glands. But besides this, endocrine cells are found in almost all tissues of the body.

The functions of the endocrine system are:

  • coordination of the work of all organs, as well as body systems;
  • participation in chemical reactions that occur in the body;
  • ensuring the stability of the vital processes of the body;
  • together with the immune and nervous systems, regulation of human growth and development of the body;
  • participation in the regulation of the functions of the human reproductive system, its sexual differentiation;
  • participation in the formation of human emotions, his emotional behavior

The structure of the disease and the endocrine system, arising from the disruption of the functioning of its components.

I. Endocrine glands

Endocrine glands make up the glandular part of the endocrine system and produce hormones. These include:

Thyroid- the largest endocrine gland. Produces the hormones calcitonin, thyroxine and triiodothyronine. They are involved in the regulation of the processes of development, growth and differentiation of tissues, increase the level of oxygen consumption by tissues and organs and the intensity of metabolism.
Diseases that are associated with dysfunction of the thyroid gland are: cretinism, hypothyroidism, Basedow's disease, thyroid cancer, Hashimoto's goiter.

parathyroid glands produce a hormone responsible for the concentration of calcium - parathyroid hormone. This hormone is essential for regulating the normal functioning of the nervous and motor systems.
Diseases associated with disruption of the parathyroid glands are hyperparathyroidism, parathyroid osteodystrophy, hypercalcemia.

Thymus (thymus) produces T-cells of the immune system and thymopoietins - hormones that are responsible for the maturation and performance of mature cells of the immune system. In other words, the thymus is involved in the important process of developing and regulating immunity. Thus, it can be argued that diseases of the immune system are associated with impaired functioning of the thymus gland.

Pancreas- an organ of the digestive system. It produces two hormones - insulin and glucagon. Glucagon increases the concentration of glucose in the blood, and insulin - to reduce it. Two of these hormones are most importantly involved in the regulation of carbohydrate and fat metabolism. Therefore, diseases associated with dysfunction of the pancreas include problems with excess weight and diabetes.

adrenal glands- the main source of adrenaline and norepinephrine. Dysfunction of the adrenal glands leads to a wide range of diseases - vascular diseases, myocardial infarction, hypertension, heart disease.

ovaries- a structural element of the female reproductive system. The endocrine function of the ovaries is the production of female sex hormones - progesterone and estrogen. Diseases associated with ovarian dysfunction - mastopathy, fibroids, ovarian cysts, infertility, endometriosis, ovarian cancer.

testicles- a structural element of the male reproductive system. Produce male sex cells and testosterone. Violation of the function of the testicles leads to malfunctions in the male body, male infertility.
The diffuse part of the endocrine system is formed by the following gland.

The endocrine system occupies a special place among the internal structures of a person. This is due to the fact that its activity extends to all organs and tissues.

General information

A certain number of cells are collected together. They form the glandular apparatus - intrasecretory glands. The compounds that the structure produces penetrate directly into the cells through the intercellular substance or are carried with the blood. The science that carries out the general study of structure is biology. The endocrine system is of great importance for a person and performs the most important functions in ensuring normal life.

Structure functions

The endocrine system of the body takes part in chemical processes, coordinates the activities of all organs and other structures. It is responsible for the stable course of life processes in conditions of constant changes in the external environment. Like the immune and nervous systems, the endocrine system is involved in the control of human development and growth, the functioning of the reproductive organs, and sexual differentiation. Its activity also extends to the formation of emotional reactions, mental behavior. The endocrine system is, among other things, one of the generators of human energy.

The constituent elements of the structure

The endocrine system of the body includes intrasecretory elements. In their totality, they constitute the glandular apparatus. It produces some hormones of the endocrine system. In addition, almost every structure cells are present. A group of endocrine cells scattered throughout the body forms the diffuse part of the system.

Intrasecretory elements

The glandular apparatus includes the following intrasecretory systems:

diffuse part

The main element that includes the endocrine system in this case is pituitary. This gland of the diffuse part of the structure is of particular importance. It can be called the central body. The pituitary gland closely interacts with the hypothalamus, forming the pituitary-hypothalamic apparatus. Thanks to him, the regulation of the interaction of compounds produced by the pineal gland is carried out.

The central organ produces compounds that stimulate and regulate the endocrine system. The anterior pituitary gland produces six essential substances. They are called dominant. These include, in particular, adrenocorticotropic hormone, thyrotropin, four gonadotropic compounds that control the activity of the sexual elements of the structure. Somatropin is also produced here. This is a very important connection for a person. Somatropin is also called growth hormone. It is the main factor influencing the development of the bone, muscle and cartilage apparatus. With excessive production of somatropin in adults, agrokemalia is diagnosed. This pathology is manifested in an increase in the bones of the face and limbs.

epiphysis

It produces the regulation of water balance in the body, as well as oxytocin. The latter is responsible for the contractility of smooth muscles (including the uterus during childbirth). In the epiphysis, hormonal compounds are produced. These include norepinephrine and melatonin. The latter is a hormone responsible for the sequence of phases during sleep. With the participation of norepinephrine, the regulation of the nervous and endocrine systems, as well as blood circulation, is carried out. All components of the structure are interconnected. When any element falls out, the regulation of the endocrine system is disturbed, as a result of which failures occur in other structures.

General information about pathologies

Systems are expressed in states associated with hyper-, hypo- or dysfunction of the intrasecretory glands. Currently, medicine knows quite a lot of different therapeutic methods that can correct the activity of the structure. They influence the choice of adequate options that correct the functions that the endocrine system has, the symptoms, the type and stage of the pathology, and the individual characteristics of the patient. As a rule, complex therapy is used for major diseases. This choice is due to the fact that the endocrine system is a rather complex structure, and the use of any one option to eliminate the causes of failure is not enough.

Steroid therapy

As mentioned above, the endocrine system is a structure whose elements carry out the production of chemical compounds involved in the activities of other organs and tissues. In this regard, the main method of eliminating certain failures in the production of substances is steroid therapy. It is applied, in particular, when an insufficient or excessive content of compounds produced by the endocrine system is diagnosed. Treatment with steroids is mandatory after a series of operations. Therapy, as a rule, involves a special scheme for taking drugs. After partial or complete removal of the gland, for example, the patient is prescribed a lifelong intake of hormones.

Other drugs

For many pathologies that affect the endocrine system, treatment involves taking general tonic, anti-inflammatory, antibiotic agents. Radioactive iodine therapy is also often used. In cancer pathologies, radioactive irradiation is used to destroy pathologically dangerous and damaged cells.

The list of medicines used to normalize the endocrine system

Many medicines are based on natural ingredients. Such agents are more preferable in the treatment of a number of diseases. The activity of the active substances of such drugs is aimed at stimulating metabolic processes and normalizing the hormonal background. Specialists distinguish especially the following drugs:

  • "Omega Q10". This remedy strengthens the immune system and normalizes the functions of the endocrine glands.
  • "Flavit-L". This drug is designed to treat and prevent disorders of the endocrine system in women.
  • "Detovit". This tool is quite powerful and is used for chronic disorders of the functioning of the intrasecretory glands.
  • "Apollo-IVA". This tool has the ability to stimulate the immune and endocrine systems.

Surgery

Surgical methods are considered the most effective in the treatment of endocrine pathologies. However, they are used as a last resort if possible. One of the direct indications for the appointment of surgical intervention is a tumor that threatens a person's life. Given the severity of the pathology, part of the gland or the organ can be removed completely. With cancerous tumors, tissues near the foci are also subject to removal.

Alternative methods of treatment of diseases of the endocrine system

Due to the fact that a large number of medicines presented today in the pharmacy network have a synthetic basis and have a number of contraindications, herbal treatment is becoming increasingly popular. However, it should be noted that the use of herbal remedies without the advice of a specialist can be dangerous. Among the most common recipes, we note a few. So, for hyperthyroidism, a herbal collection is used, which includes (4 parts), catnip grass (3 hours), oregano (3 hours), peppermint (leaves), motherwort (1 hour). Raw materials need to take two tablespoons. The collection is poured with boiling water (five hundred milliliters) and insisted overnight in a thermos. In the morning it is filtered. Take 1/2 cup before meals three times a day. Duration of admission - two months. After two or three months, the course is repeated.

Obese people are recommended decoctions and infusions that reduce appetite and increase the release of interstitial fluid from the body. Regardless of which folk recipe is chosen, the funds should be used only after visiting the doctor.

The endocrine and nervous systems regulate all functions of the human body. However, the endocrine system regulates mainly more general processes: metabolism, body growth, reproduction (development) of germ cells. The endocrine system includes endocrine glands that secrete a secret (hormone) into the blood or lymph. Therefore, the endocrine glands are better vascularized than the exocrine glands, and in addition, there are no excretory ducts in the endocrine glands.

MICROCIRCULATORY BED OF ENDOCRINE GLANDS is characterized by three features: 1) the presence of sinusoidal capillaries; 2) the presence of fenestrated endotheliocytes; 3) the presence of a pericapillary space.

NATURE (COMPOSION) OF HORMONES. Hormones are most often protein substances and amino acid derivatives, and less often hormones are steroids, the precursors of which are lipids. Steroids are produced only in the adrenal glands and gonads.

Some hormones are produced only in one gland, for example, thyroxine is produced in the thyroid gland, while insulin is produced in the pancreas, parotid gland, thymus, and some brain cells.

There are individual endocrine cells that produce several hormones. For example, the G cells of the gastric mucosa produce gastrin and enkephalin.

Hormones do not affect all organs, but only those in the cells of which there are receptors for this hormone. These cells (organs) are called target cells or effectors.

THE MECHANISM OF THE IMPACT OF HORMONES ON TARGET CELLS. When the receptor captures the target cell of the hormone, a receptor-hormonal complex is formed, under the influence of which adenylate cyclase is activated. Adenylate cyclase causes the synthesis of cAMP (cyclic adenosine monophosphate-signaling molecule), which stimulates the enzymatic systems of the cell.

RELATIONSHIP OF THE ENDOCRINE AND NERVOUS SYSTEMS: 1) the endocrine system is innervated by the nervous system; 2) both nerve cells and endocrinocytes produce biologically active substances (endocrinocytes produce hormones, neurons are mediators of synapses); 3) in the hypothalamus there are neurosecretory cells that produce hormones (vasopressin, oxytocin, Riesling hormones); 4) some glands are of neurogenic origin (medullary pineal gland and adrenal medulla).

CLASSIFICATION OF THE ENDOCRINE SYSTEM. The endocrine system is subdivided into: I central endocrine organs (hypothalamus, pineal gland, pituitary gland); II peripheral endocrine organs: 1) endocrine glands (thyroid, parathyroid, adrenal); 2) mixed organs that perform endocrine and non-endocrine functions (pancreas, placenta, gonads); 3) individual endocrine cells diffusely scattered in organs and tissues - diffuse endocrine system (DES), which is divided into: a) cells of neurogenic origin, characterized by the ability to absorb and decarboxylate amine precursors, secrete oligopeptide hormones and neuroamines, stain with heavy metal salts , the presence of dense secretory granules in the cytoplasm; b) having no neurogenic origin - interstitial cells of the gonads, capable of producing steroid hormones.

Depending on the functional features, the organs of the endocrine system are divided into 1) neuroendocrine transducers (switches) that release neurotransmitters (intermediaries) - liberins and statins; 2) neurohemal organs (medial elevation of the hypothalamus and posterior pituitary gland), which do not produce their own hormones, but hormones from other parts of the hypothalamus come to them and accumulate here; 3) the central organ (adenohypophysis), which regulates the function of peripheral endocrine glands and non-endocrine organs; 4) peripheral endocrine glands and structures that are divided into a) adenohypophysis-dependent (thyroid gland, adrenal cortex, sex) glands and b) adenohypophysis-independent glands (parathyroid, calcitoninocytes of the thyroid gland, adrenal medulla).

The hypothalamus develops from the basal part of the middle cerebral bladder and is divided into anterior, middle (mediobasal), and posterior. The hypothalamus is closely connected to the pituitary gland through two systems: 1) the hypothalamic-adenohypophyseal system, through which the hypothalamus communicates with the anterior and middle lobes of the pituitary gland, and 2) the hypothalamus-neurohypophysis, through which the hypothalamus is connected to the posterior pituitary gland (neurohypophysis).

Each of these systems has its own neurohemal organ; an organ in which hormones are not produced, but enter it from the hypothalamus and accumulate here. The neurohemal organ of the hypothalamic-adenohypophyseal system is the median eminence (eminentia medialis), and in the second system, the posterior lobe of the pituitary gland.

CHARACTERISTIC SIGNS OF THE NEUROHEMALE ORGANS: 1) the system of capillaries is well developed; 2) there are axovasal synapses; 3) able to accumulate neurohormones; 4) the axons of neurosecretory cells end in it.

NEUROSECRETORY NUCLEI OF THE HYPOTHALAMUS are represented by 30 pairs, however, we will consider only 8 pairs of nuclei. Some of them contain large cholinergic, others small adrenergic neurosecretory cells capable of proliferation.

THE NUCLEI OF THE ANTERIOR HYPOTHALAMUS are represented by two pairs: 1) supraoptic (nucleus supraopticus) and 2) paraventricular (nucleus paraventricularis). These two nuclei contain large, cholinergic neurosecretory cells capable of synthesizing peptides and acetylcholines. In addition, the composition of the paraventricular nuclei includes small, adrenergic, neurosecretory cells. Large cholinergic and small adrenergic neurosecretory cells are able not only to produce neurohormones, but also to generate and conduct a nerve impulse.

Large cholinergic neurons are capable of proliferation, contain dense secretory granules, secrete two hormones: vasopressin (antidiuretic hormone - ADH) and oxytocin. Oxytocin is produced predominantly in the paraventricular nuclei.

ACTION OF VAZOPRESSIN: 1) narrowing of blood vessels and increase in arterial pressure; 2) increased reabsorption (reabsorption) of water from the renal tubules, i.e. decrease in diuresis.

ACTION OF OXYTOCIN: 1) reduction of myoepithelial cells of the terminal sections of the mammary glands, resulting in increased milk secretion; 2) contraction of the muscles of the uterus; 3) contraction of the smooth muscles of the male vas deferens.

Vasopressin and oxytocin in the form of dense granules are contained in the body and axons of neurosecretory cells of the supraoptic and paraventricular nuclei. Along the axons, these 2 hormones are transported to the neurohemal organ - the posterior pituitary gland and are deposited near the blood vessels - Herring's storage bodies.

NUCLEI OF THE MEDIOBASAL (MIDDLE) HYPOTHALAMUS are represented by six neurosecretory nuclei: 1) arcuate (nucleus arcuatus) or infundibular (nucleus infundibularis); 2) ventromedial (nucleus ventramedialis); 3) dorsomedial (nucleus dorsomedialis); 4) suprachiasmatic (nucleus suprahiasmaticus); 5) gray periventricular substance (substantia periventricularis grisea) and 6) preoptic zone (zona preoptica).

The largest nuclei are infundibular and ventromedial. Each of these 6 nuclei contains small adrenergic neurosecretory cells capable of active proliferation, production and conduction of a nerve impulse and contain dense granules filled with adenohypophysotropic hormones: liberins and statins (Riesling hormones).

ADENOHYPOPHYSOTROPIC HORMONES affect the adenohypophysis: liberins stimulate its function, statins inhibit it. Liberins and statins differ in their action from each other. In particular, thyroliberins stimulate the release of thyrotropin by the pituitary gland, gonadoliberins - the release of gonadotropin, corticoliberins - the release of corticotropin (ACTH); statins inhibit the release of hormones: thyrostatin thyrotropin, gonadostatin-gonadotropin, corticostatin-ACTH, etc.

REGULATION OF THE FUNCTION OF PERIPHERAL ENDOCRINE GLANDS BY THE HYPOTHALAMUS. There are 2 ways of regulation: 1) through the pituitary gland (transhypophyseal pathway); 2) bypassing the pituitary gland (parahypophyseal pathway).

The pituitary pathway is characterized by the fact that adenohypophysotropic hormones (liberins and statins) are produced in the mediobasal hypothalamus, which are transported with blood to the anterior pituitary gland. Under the influence of liberins, tropic hormones of the pituitary gland (gonadotropic, thyrotropic, corticotropic, etc.) are produced and released, which reach the corresponding glands with the blood flow (corticotropic to the adrenal cortex, etc.) and stimulate their function.

PARAGIPOPHYSAL WAY regulation is carried out using three methods: 1) sympathetic and parasympathetic regulation of peripheral glands. The hypothalamus is the highest center of regulation of the sympathetic and parasympathetic nervous system, and through the sympathetic and parasympathetic nerve fibers, it regulates the function of all glands; an example of autonomic nervous regulation is the neuron of the paraventricular nucleus; the nerve cell of the dorsal nucleus of the vagus; the pancreas; the secretion of insulin; at the same time, neurohumoral regulation is carried out, for example, a small cell neuron of the paraventricular nucleus, the anterior lobe of the pituitary gland, secretion of ACTH by the adrenal cortex, secretion of glucocorticoids, inhibition of insulin secretion; an example with the participation of the immune system - macrophage - secretion of IL-1 paraventricular nucleus secretion of corticoliberin anterior pituitary - secretion of ACTH adrenal cortex secretion of glucocorticoids macrophage - inhibition of secretion of IL-1; 2) regulation is carried out according to the principle of "negative feedback". This principle is divided into 2 more ways: a) if the level of the hormone of this gland is high in the blood, then the secretion of this hormone is suppressed, if its level in the blood is low, it is stimulated; b) if the effect caused by the hormone increases, then the release of this hormone is suppressed. For example: increased parathyrin secretion by the parathyroid gland, as a result of which the level of calcium in the blood rises - this is an effect caused by parathyrin. A high level of calcium in the blood inhibits the release of parathyrin, if the level of Ca in the blood is low, then the secretion of parathyrin increases; 3) the third way is that sometimes thyrotropic (stimulating thyroid function) immunoglobulins or autoantibodies are produced in the body, which are captured by thyroid cell receptors and stimulate their function for a long time. The pituitary gland consists of the anterior lobe (lobus anterior), the intermediate part (pars intermedia) and the posterior lobe, or neurohypophysis (lobus posterior).

DEVELOPMENT OF THE HYPOPHYSIS. The pituitary gland develops from 1) the epithelium of the roof of the oral cavity, which itself develops from the ectoderm, and 2) the distal end of the infundibulum of the bottom of the 3rd ventricle. From the epithelium of the oral cavity (ectoderm), the adenohypophysis develops at 4-5 weeks of embryogenesis as a result of protrusion of the epithelium of the oral cavity towards the bottom of the 3rd ventricle, a pituitary pocket is formed. A funnel from the bottom of the 3rd ventricle grows towards the pituitary pocket. When the distal end of the funnel is aligned with the pituitary pocket, the anterior wall of this pocket thickens and turns into the anterior lobe, the posterior one into the intermediate part, and the distal end of the funnel into the posterior lobe of the pituitary gland.

ADENOHYPOPHISIS (adenohypophysis) includes the anterior lobe, the intermediate part and the tubal part, i.e. everything that develops from the pituitary pocket (Rathke's pocket).

The anterior lobe (lobus anterior) is covered with a connective tissue capsule, from which layers of loose connective tissue extend deep into, forming the stroma of the lobe. Blood and lymphatic vessels pass through the layers. Between the layers are strands of epithelial cells (adenocytes) that form the parenchyma of the lobe. CLASSIFICATION OF ADENOCYTES. The cells of the anterior lobe are divided into: 1) chromophilic and 2) chromophobic (main). Chromophilic are so named because their cytoplasm contains granules that can be stained with dyes; chromophobic ones do not contain such granules, therefore their cytoplasm is not stained. In the anterior lobe there are cells that are neither chromophilic nor chromophobic; these are corticotropic adenocytes.

CHROMOPHILIC ADENOCYTES (endocrinocytus chromophilus) are divided into: 1) basophilic, in the cytoplasm of which there are granules stained with basic dyes, and 2) acidophilic, the granules of which are stained with acidic dyes.

BASOPHYL ENDOCRINOCYTES (ADENOCYTES) account for 4-10%. They are divided into 2 subgroups: 1) gonadotropic and 2) thyrotropic.

GONADOTROPIC ENDOCRINOCYTES are the largest cells, have a round, sometimes angular shape, an oval or round nucleus, displaced to the periphery, since in the center of the cell there is a macula (spot) in which the Golgi complex and the cell center are located. In the cytoplasm, granular EPS, mitochondria and the Golgi complex are well developed, as well as basophilic granules 200–300 nm in diameter, consisting of glycoproteins and stained with aldehyde fuchsin.

Gonadotropic endocrinocytes produce 2 gonadotropic hormones: 1) luteinizing, or luteotropic hormone (lutropin) and 2) follicle-stimulating, or folliculotropic hormone (folitropin).

FOLICULOTROPIC HORMONE (FOLITROPIN) in the male body acts on the initial stage of spermatogenesis, in the female - on the growth of follicles and the release of estrogens in the gonads.

LUTROPIN stimulates the secretion of testosterone in the male gonads and the development and function of the corpus luteum in the female gonads.

It is believed that there are 2 varieties of gonadotropic endocrinocytes, some of which secrete folitropin, others - lutropin.

Castration cells appear in the anterior lobe when the gonads produce an insufficient amount of sex hormones. Then, in gonadotropic cells, the macula increases and pushes the cytoplasm and nucleus to the periphery. At the same time, the cell hypertrophies, actively secretes gonadotropic hormone in order to stimulate the production of sex hormones. Gonadotropic adenocyte at this time takes the form of a ring.

THYROTROPIC ENDOCRINOCYTES have an oval or elongated shape, an oval nucleus. In their cytoplasm, the Golgi complex, granular ER and mitochondria are well developed, contain basophilic granules 80-150 nm in size, stained with aldehyde fuchsin. Thyrotropic endocrinocytes under the influence of thyroliberin produce thyrotropic hormone, which stimulates the release of thyroxine by the thyroid gland.

THYROIDECTOMY CELLS appear in the pituitary gland when the thyroid function is reduced. In these cells, granular EPS hypertrophies, its cisterns expand, and the secretion of thyrotropic hormone increases. As a result of the expansion of the tubules and cisterns of the EPS, the cytoplasm

cells become cellular.

CORTICOTROPIC ENDOCRINOCYTES are neither acidophilic nor basophilic, they have an irregular shape, a lobed nucleus, their cytoplasm contains small granules. Under the influence of corticoliberins produced in the nuclei of the mediobasal hypothalamus, these cells secrete corticotropic, or adrenocorticotropic hormone (ACTH), which stimulates the function of the adrenal cortex.

ACIDOPHILIAN ENDOCRINOCYTES make up 35-40% and are divided into 2 varieties: 1) somatotropic and 2) mammotropic endocrinocytes. Both varieties are usually round in shape, with an oval or round core located in the center. The synthetic apparatus is well developed in the cells, i.e. Golgi complex, granular ER, mitochondria, the cytoplasm contains acidophilic granules.

SOMATOTROPIC ENDOCRINOCYTES contain oval or round granules with a diameter of 400-500 nm, produce somatotropic hormone, which stimulates body growth in childhood and adolescence. With hyperfunction of somatotropic cells, after completion of growth, acromigalia disease develops, characterized by the appearance of a hump, an increase in the size of the tongue, lower jaw, hands and feet.

MAMMOTROPIC ENDOCRINOCYTES contain elongated granules reaching sizes of 500-600 nm in parturients and pregnant women. In non-nursing mothers, the granules are reduced to 200 nm. These adenocytes secrete mammatropic hormone, or prolactin. FUNCTIONS: 1) stimulates the synthesis of milk in the mammary glands; 2) stimulates the development of the corpus luteum in the ovaries and the secretion of progesterone.

CHROMOPHOBIC (MAIN) ENDOCRINOCYTES make up about 60%, have smaller sizes, do not contain stained granules, therefore their cytoplasm is not stained. The composition of chromophobic adenocytes includes 4 groups: 1) undifferentiated (perform a regenerative function); 2) differentiating, i.e. they began to differentiate, but differentiation did not end, only single granules appeared in the cytoplasm, so the cytoplasm is weakly stained; 3) chromophilic mature cells that have just released their secretory granules, therefore, have decreased in size, and the cytoplasm has lost the ability to stain; 4) stellate follicular cells are characterized by long processes extending between endocrinocytes. A group of such cells, facing each other with their apical surfaces, secretes a secret, resulting in the formation of pseudofollicles filled with colloid.

The intermediate part of the adenohypophysis is represented by an epithelium located in several layers located between the anterior and posterior lobes of the pituitary gland. In the intermediate part there are pseudofollicles containing a colloid-like mass. FUNCTIONS: 1) secretion of a melanotropic (melanocytostimulating) hormone that regulates the metabolism of melanin pigment; 2) lipotropic hormone that regulates lipid metabolism.

The tuberal part of the adenohypophysis (pars tuberalis) is located next to the pituitary stalk, consists of intertwining strands of cuboidal epithelial cells, richly vascularized. The function has been little studied.

HYPOTHALAMOHYPOPHISAL CIRCULATION SYSTEM (PORTAL SYSTEM). This system originates from the pituitary arteries, which branch into a primary capillary network in the region of the median eminence (the neurohemal organ of the hypothalamic-adenohypophyseal system). The capillaries of this network flow into 10-12 portal veins running in the pituitary stalk. The portal veins reach the anterior lobe and branch into a secondary capillary network. The capillaries of the secondary network flow into the efferent veins of the pituitary gland, i.e. these capillaries are located between the veins (portal and efferent) and therefore form a wonderful network.

THE ROLE OF THE PORTAL SYSTEM IN THE REGULATION OF THE FUNCTION OF THE ADENOGYPOPHISIS. Axons of neurosecretory cells that produce liberins and statins from the mediobasal hypothalamus are directed to the median eminence and end in axovasal synapses on the capillaries of the primary network. Through these synapses, liberins or statins enter the bloodstream of these capillaries and are then transported through the portal veins to the secondary capillary network. Through the capillary wall, liberins or statins enter the parenchyma of the anterior lobe and are captured by the receptors of endocrine cells (thyroliberins are captured by thyrotropic adenocytes, gonadoliberins are gonadotrotropic adenocytes, etc.). As a result, tropic hormones are released from adenocytes, which enter the capillaries of the secondary network and are transported with the blood flow to the corresponding glands.

The posterior lobe of the pituitary gland (neurohypophysis) is represented mainly by ependymal glia. Neuroglia cells are called pituicytes. Hormones are not produced in the neurohypophysis (it is a neurohemal organ). The axons of the neurosecretory cells of the supraoptic and paraventricular nuclei enter the posterior lobe. These axons transport vasopressin and oxytocin to the posterior lobe and accumulate at the axon terminals near the blood vessels. These accumulations are called storage bodies, or Herring bodies. As needed, hormones from these bodies enter the blood vessels.

EPIFZ, OR PINEAL GLAND (epiphysis cerebri) develops from the bottom of the 3rd cerebral bladder from two protrusions. One protrusion is called the epiphyseal, the second is called the subcommissural organ. Then both protrusions merge and the parenchyma of the epiphysis is formed from them.

The epiphysis is covered with a connective tissue membrane, from which layers extend deep into, dividing the parenchyma into lobules and forming the stroma of the gland. The parenchyma of the lobules includes 2 types of cells: 1) supporting gliocytes (gliocytus cenralis) and 2) pinealocytes (endocrinocytus pinealis). Pinealocytes are divided into 1) light (endocrinocytus lucidus) and 2) dark (endocrinocytus densus). In both types of pinealocytes, the nuclei are large, round, mitochondria, granular ER, and the Golgi complex are well developed. From the bodies of pinealocytes, processes extend, ending in thickenings on the capillaries along the periphery of the lobule. There are secretory granules in the processes and in the body.

FUNCTIONS OF THE EPIPHYSIS: 1) regulates the rhythmic processes associated with the dark and light periods of the day (circadian, or daily rhythms), as well as the sexual cycle in the female body. Light impulses enter the pineal gland in the following way. At the moment when the light pulse passes through the optic chiasm (hiasma opticum) in the suprachiasmatic nucleus, the nature of the discharges changes, which affects the blood flow in the capillaries. From here, the supraoptic nucleus is influenced in a humoral way, from where the impulses arrive at the lateral-intermediate nucleus of the cervical part of the spinal cord, and from there along the fibers to the superior cervical sympathetic ganglion, the axons of the neurons of this sympathetic ganglion carry the impulse to the epiphysis; 2) the pineal gland performs an antigonadotropic function, i.e. inhibits the premature development of the reproductive system. This is done in the following way. During the day, serotonin is produced in pinealocytes, which turns into melatonin, which has an antigonadotropic effect, that is, it inhibits the secretion of luliberin in the hypothalamus and lutropin in the pituitary gland. In addition, a special antigonadotropic hormone is produced in the epiphysis, which inhibits the gonadotropic function of the anterior pituitary gland; 3) the pineal gland produces a hormone that regulates the content of potassium in the blood; 4) secretes aginin-vasotocin, which constricts blood vessels; 5) secretes luliberin, thyroliberin and thyrotropin; 6) secretes adreno-glomerulotropin, which stimulates the secretion of aldosterone in the glomerular zone of the adrenal cortex. In total, about 40 hormones are produced in the pineal gland.

AGE CHANGES OF THE EPIPHYSIS are characterized by the fact that by the age of 6 years it fully develops and remains in this state up to 20-30 years, then undergoes involution. In the lobules of the epiphysis, calcium carbonate salts and phosphorus salts are deposited, layering on each other. As a result, brain sand is formed, which has a layered structure.

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