How Does the Endocrine System Interact with the Environment?

The endocrine system consists of glands or parts of glands which produce hormones that are released and distributed in the human body by means of the bloodstream. The major organs of the endocrine system are the hypothalamus, the pituitary gland, the thyroid gland, the parathyroid glands, the islets of the pancreas, the adrenal glands, the testes, and the ovaries.

Humans have two systems of internal communication: the nervous system and the endocrine system. The endocrine system controls the delivery of messages through the release of chemicals known as hormones. Hormones are secreted directly into the blood by endocrine glands. Endocrine glands are found throughout the body and are responsible for releasing more than 50 hormones that control a number of essential functions in the body, including growth and development.

The Brain

Hypothalamus

The Hypothalamus contains vital centers for controlling the automatic nervous system, body temperature and water and food intake, and is the center for primitive physical and emotional behavior.

Pituitary

The pituitary gland is the master gland of the body. Compared with other endocrine glands, it produces the largest number of hormones, including some that control the other endocrine glands of the body.

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The Thyroid & Parathyroid

The first organ recognized as an endocrine gland was the thyroid. It consists of two bodies like small walnuts: they are connected by an isthmus beside the larynx (voice box).
The parathyroids are four small glands attached to the thyroid gland, which act to maintain normal levels of calcium and phosphate in the blood and thus normal function of muscles and nerves.

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The Pancreas

The islets of the pancreas produce hormones necessary for the regulation of blood sugar levels – insulin and glucagons. The alpha cells of the islets secrete glucagon, which raises blood glucose (sugar) levels by stimulating the breakdown of liver glycogen. When blood sugar levels are too high, the beta cells of the pancreas secrete insulin which stimulates the uptake of glucose.

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Adrenal

The suprarenal or adrenal glands, each perched over one of the kidneys, are double glands. The core, or medulla, manufactures adrenalin, noradrenalin and a small amount of dopamine.

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The

Reproductive Organs

Ovaries

These double organs are the sex glands. The ovaries in females produce the egg cell (ova). They also produce sex hormones that flow through the blood and give rise to such secondary traits as the breasts of the female.

Testes

These double organs are the sex glands. The testes in males produce the germinating cells, the sperm cells. They also produce sex hormones that flow through the blood and give rise to such secondary traits as the beard of the male.

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Your endocrine system | University of Iowa Hospitals & Clinics

The endocrine system is the glands that release hormones into the circulatory system. These hormones do a lot of things, like create the insulin that controls sugar in the body. When these parts of the body become irregular and a tumor forms, it can be especially dangerous because it can affect the production of hormones in your body.

These are some of the parts of the body that make up the endocrine system.

Thyroid gland

Located at the front of the neck, the thyroid gland controls the body’s metabolism by producing and releasing thyroid hormone.

Parathyroid glands

The parathyroid glands are tiny glands that secrete parathyroid hormone (PTH), which controls calcium metabolism.

Pancreas

Located in the middle of the abdomen, the pancreas has cells that make digestive enzymes and cells that make hormones.

Adrenal glands

Paired organs that are located above the kidneys, the adrenal glands are controlled by the pituitary gland.

Carcinoid tumors

Carcinoid tumors are rare masses that most commonly originate from hormone-producing cells of the intestines and lung.

Multiple endocrine neoplasia (MEN) syndromes

Multiple endocrine neoplasia syndromes are a group of inheritable syndromes that cause tumors in multiple endocrine organs.

Diagnostic tests

In order to ensure the right diagnosis, we have an assortment of advanced diagnostic tests.

Minimally invasive endocrine surgery

When surgeons talk about minimally invasive endocrine surgery, what they mean is a surgery using techniques to make as small an incision as possible. The reason minimally invasive surgery is so often used is it is less dangerous than other surgical techniques and it can often cut down on recovery time.

What to do before endocrine surgery

To aid in a safe surgery, there are a few things you have to do before having endocrine surgery.

16.4: Endocrine System – Biology LibreTexts

The endocrine system produces hormones that function to control and regulate many different body processes. The endocrine system coordinates with the nervous system to control the functions of the other organ systems. Cells of the endocrine system produce molecular signals called hormones. These cells may compose endocrine glands, may be tissues or may be located in organs or tissues that have functions in addition to hormone production. Hormones circulate throughout the body and stimulate a response in cells that have receptors able to bind with them. The changes brought about in the receiving cells affect the functioning of the organ system to which they belong. Many of the hormones are secreted in response to signals from the nervous system, thus the two systems act in concert to effect changes in the body.

Hormones

Maintaining homeostasis within the body requires the coordination of many different systems and organs. One mechanism of communication between neighboring cells, and between cells and tissues in distant parts of the body, occurs through the release of chemicals called hormones. Hormones are released into body fluids, usually blood, which carries them to their target cells where they elicit a response. The cells that secrete hormones are often located in specific organs, called endocrine glands, and the cells, tissues, and organs that secrete hormones make up the endocrine system. Examples of endocrine organs include the pancreas, which produces the hormones insulin and glucagon to regulate blood-glucose levels, the adrenal glands, which produce hormones such as epinephrine and norepinephrine that regulate responses to stress, and the thyroid gland, which produces thyroid hormones that regulate metabolic rates.

The endocrine glands differ from the exocrine glands. Exocrine glands secrete chemicals through ducts that lead outside the gland (not to the blood). For example, sweat produced by sweat glands is released into ducts that carry sweat to the surface of the skin. The pancreas has both endocrine and exocrine functions because besides releasing hormones into the blood. It also produces digestive juices, which are carried by ducts into the small intestine.

CAREER IN ACTION: Endocrinologist

An endocrinologist is a medical doctor who specializes in treating endocrine disorders. An endocrine surgeon specializes in the surgical treatment of endocrine diseases and glands. Some of the diseases that are managed by endocrinologists include disorders of the pancreas (diabetes mellitus), disorders of the pituitary (gigantism, acromegaly, and pituitary dwarfism), disorders of the thyroid gland (goiter and Graves’ disease), and disorders of the adrenal glands (Cushing’s disease and Addison’s disease).

Endocrinologists are required to assess patients and diagnose endocrine disorders through extensive use of laboratory tests. Many endocrine diseases are diagnosed using tests that stimulate or suppress endocrine organ functioning. Blood samples are then drawn to determine the effect of stimulating or suppressing an endocrine organ on the production of hormones. For example, to diagnose diabetes mellitus, patients are required to fast for 12 to 24 hours. They are then given a sugary drink, which stimulates the pancreas to produce insulin to decrease blood-glucose levels. A blood sample is taken one to two hours after the sugar drink is consumed. If the pancreas is functioning properly, the blood-glucose level will be within a normal range. Another example is the A1C test, which can be performed during blood screening. The A1C test measures average blood-glucose levels over the past two to three months. The A1C test is an indicator of how well blood glucose is being managed over a long time.

Once a disease such as diabetes has been diagnosed, endocrinologists can prescribe lifestyle changes and medications to treat the disease. Some cases of diabetes mellitus can be managed by exercise, weight loss, and a healthy diet; in other cases, medications may be required to enhance insulin’s production or effect. If the disease cannot be controlled by these means, the endocrinologist may prescribe insulin injections.

In addition to clinical practice, endocrinologists may also be involved in primary research and development activities. For example, ongoing islet transplant research is investigating how healthy pancreas islet cells may be transplanted into diabetic patients. Successful islet transplants may allow patients to stop taking insulin injections.

How Hormones Work

Hormones cause changes in target cells by binding to specific cell-surface or intracellularhormone receptors, molecules embedded in the cell membrane or floating in the cytoplasm with a binding site that matches a binding site on the hormone molecule. In this way, even though hormones circulate throughout the body and come into contact with many different cell types, they only affect cells that possess the necessary receptors. Receptors for a specific hormone may be found on or in many different cells or may be limited to a small number of specialized cells. For example, thyroid hormones act on many different tissue types, stimulating metabolic activity throughout the body. Cells can have many receptors for the same hormone but often also possess receptors for different types of hormones. The number of receptors that respond to a hormone determines the cell’s sensitivity to that hormone, and the resulting cellular response. Additionally, the number of receptors available to respond to a hormone can change over time, resulting in increased or decreased cell sensitivity. In up-regulation, the number of receptors increases in response to rising hormone levels, making the cell more sensitive to the hormone and allowing for more cellular activity. When the number of receptors decreases in response to rising hormone levels, called down-regulation, cellular activity is reduced.

Endocrine Glands

The endocrine glands secrete hormones into the surrounding interstitial fluid; those hormones then diffuse into blood and are carried to various organs and tissues within the body. The endocrine glands include the pituitary, thyroid, parathyroid, adrenal glands, gonads, pineal, and pancreas.

The pituitary gland, sometimes called the hypophysis, is located at the base of the brain (Figure \(\PageIndex{1}\)a). It is attached to the hypothalamus. The posterior lobe stores and releases oxytocin and antidiuretic hormone produced by the hypothalamus. The anterior lobe responds to hormones produced by the hypothalamus by producing its own hormones, most of which regulate other hormone-producing glands.

Figure \(\PageIndex{1}\): (a) The pituitary gland sits at the base of the brain, just above the brain stem. (b) The parathyroid glands are located on the posterior of the thyroid gland. (c) The adrenal glands are on top of the kidneys. d) The pancreas is found between the stomach and the small intestine. (credit: modification of work by NCI, NIH)

The anterior pituitary produces six hormones: growth hormone, prolactin, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, and luteinizing hormone. Growth hormone stimulates cellular activities like protein synthesis that promote growth. Prolactin stimulates the production of milk by the mammary glands. The other hormones produced by the anterior pituitary regulate the production of hormones by other endocrine tissues (Table \(\PageIndex{1}\)). The posterior pituitary is significantly different in structure from the anterior pituitary. It is a part of the brain, extending down from the hypothalamus, and contains mostly nerve fibers that extend from the hypothalamus to the posterior pituitary.

The thyroid gland is located in the neck, just below the larynx and in front of the trachea (Figure \(\PageIndex{1}\)b). It is a butterfly-shaped gland with two lobes that are connected. The thyroid follicle cells synthesize the hormone thyroxine, which is also known as T₄ because it contains four atoms of iodine, and triiodothyronine, also known as T₃ because it contains three atoms of iodine. T₃ and T₄ are released by the thyroid in response to_{thyroid-stimulating hormone produced by the anterior pituitary, and both T3 and T4 have the effect of stimulating metabolic activity in the body and increasing energy use. A third hormone, calcitonin, is also produced by the thyroid. Calcitonin is released in response to rising calcium ion concentrations in the blood and has the effect of reducing those levels.}

Most people have four parathyroid glands; however, the number can vary from two to six. These glands are located on the posterior surface of the thyroid gland (Figure \(\PageIndex{1}\)b).

The parathyroid glands produce parathyroid hormone. Parathyroid hormone increases blood calcium concentrations when calcium ion levels fall below normal.

The adrenal glands are located on top of each kidney (Figure \(\PageIndex{1}\)c). The adrenal glands consist of an outer adrenal cortex and an inner adrenal medulla. These regions secrete different hormones.

The adrenal cortex produces mineralocorticoids, glucocorticoids, and androgens. The main mineralocorticoid is aldosterone, which regulates the concentration of ions in urine, sweat, and saliva. Aldosterone release from the adrenal cortex is stimulated by a decrease in blood concentrations of sodium ions, blood volume, or blood pressure, or by an increase in blood potassium levels. The glucocorticoids maintain proper blood-glucose levels between meals. They also control a response to stress by increasing glucose synthesis from fats and proteins and interact with epinephrine to cause vasoconstriction. Androgens are sex hormones that are produced in small amounts by the adrenal cortex. They do not normally affect sexual characteristics and may supplement sex hormones released from the gonads. The adrenal medulla contains two types of secretory cells: one that produces epinephrine (adrenaline) and another that produces norepinephrine (noradrenaline). Epinephrine and norepinephrine cause immediate, short-term changes in response to stressors, inducing the so-called fight-or-flight response. The responses include increased heart rate, breathing rate, cardiac muscle contractions, and blood-glucose levels. They also accelerate the breakdown of glucose in skeletal muscles and stored fats in adipose tissue, and redirect blood flow toward skeletal muscles and away from skin and viscera. The release of epinephrine and norepinephrine is stimulated by neural impulses from the sympathetic nervous system that originate from the hypothalamus.

The pancreas is an elongate organ located between the stomach and the proximal portion of the small intestine (Figure \(\PageIndex{1}\)d). It contains both exocrine cells that excrete digestive enzymes and endocrine cells that release hormones.

The endocrine cells of the pancreas form clusters called pancreatic islets or the islets of Langerhans. Among the cell types in each pancreatic islet are the alpha cells, which produce the hormone glucagon, and the beta cells, which produce the hormone insulin. These hormones regulate blood-glucose levels. Alpha cells release glucagon as blood-glucose levels decline. When blood-glucose levels rise, beta cells release insulin. Glucagon causes the release of glucose to the blood from the liver, and insulin facilitates the uptake of glucose by the body’s cells.

The gonads—the male testes and female ovaries—produce steroid hormones. The testes produce androgens, testosterone being the most prominent, which allow for the development of secondary sex characteristics and the production of sperm cells. The ovaries produce estrogen and progesterone, which cause secondary sex characteristics, regulate production of eggs, control pregnancy, and prepare the body for childbirth.

There are several organs whose primary functions are non-endocrine but that also possess endocrine functions. These include the heart, kidneys, intestines, thymus, and adipose tissue. The heart has endocrine cells in the walls of the atria that release a hormone in response to increased blood volume. It causes a reduction in blood volume and blood pressure, and reduces the concentration of Na⁺ in the blood.

The gastrointestinal tract produces several hormones that aid in digestion. The endocrine cells are located in the mucosa of the GI tract throughout the stomach and small intestine. They trigger the release of gastric juices, which help to break down and digest food in the GI tract.

The kidneys also possess endocrine function. Two of these hormones regulate ion concentrations and blood volume or pressure. Erythropoietin (EPO) is released by kidneys in response to low oxygen levels. EPO triggers the formation of red blood cells in the bone marrow. EPO has been used by athletes to improve performance. But EPO doping has its risks, since it thickens the blood and increases strain on the heart; it also increases the risk of blood clots and therefore heart attacks and stroke.

The thymus is found behind the sternum. The thymus produces hormones referred to as thymosins, which contribute to the development of the immune response in infants. Adipose tissue, or fat tissue, produces the hormone leptin in response to food intake. Leptin produces a feeling of satiety after eating, reducing the urge for further eating.

Regulation of Hormone Production

Hormone production and release are primarily controlled by negative feedback, as described in the discussion on homeostasis. In this way, the concentration of hormones in blood is maintained within a narrow range. For example, the anterior pituitary signals the thyroid to release thyroid hormones. Increasing levels of these hormones in the blood then give feedback to the hypothalamus and anterior pituitary to inhibit further signaling to the thyroid gland (Figure \(\PageIndex{2}\)).

ART CONNECTION

Figure \(\PageIndex{2}\): The anterior pituitary stimulates the thyroid gland to release thyroid hormones T₃ and T₄. Increasing levels of these hormones in the blood result in feedback to the hypothalamus and anterior pituitary to inhibit further signaling to the thyroid gland. (credit: modification of work by Mikael Häggström)

Goiter, a disease caused by iodine deficiency, results in the inability of the thyroid gland to form T₃ and T₄. The body typically attempts to compensate by producing greater amounts of TSH. Which of the following symptoms would you expect goiter to cause?

1. Hypothyroidism, resulting in weight gain, cold sensitivity, and reduced mental activity.
2. Hyperthyroidism, resulting in weight loss, profuse sweating, and increased heart rate.
3. Hyperthyroidism, resulting in weight gain, cold sensitivity, and reduced mental activity.
4. Hypothyroidism, resulting in weight loss, profuse sweating, and increased heart rate.

Section Summary

Hormones cause cellular changes by binding to receptors on or in target cells. The number of receptors on a target cell can increase or decrease in response to hormone activity.

Hormone levels are primarily controlled through negative feedback, in which rising levels of a hormone inhibit its further release.

The pituitary gland is located at the base of the brain. The anterior pituitary receives signals from the hypothalamus and produces six hormones. The posterior pituitary is an extension of the brain and releases hormones (antidiuretic hormone and oxytocin) produced by the hypothalamus. The thyroid gland is located in the neck and is composed of two lobes. The thyroid produces the hormones thyroxine and triiodothyronine. The thyroid also produces calcitonin. The parathyroid glands lie on the posterior surface of the thyroid gland and produce parathyroid hormone.

The adrenal glands are located on top of the kidneys and consist of the adrenal cortex and adrenal medulla. The adrenal cortex produces the corticosteroids, glucocorticoids and mineralocorticoids. The adrenal medulla is the inner part of the adrenal gland and produces epinephrine and norepinephrine.

The pancreas lies in the abdomen between the stomach and the small intestine. Clusters of endocrine cells in the pancreas form the islets of Langerhans, which contain alpha cells that release glucagon and beta cells that release insulin. Some organs possess endocrine activity as a secondary function but have another primary function. The heart produces the hormone atrial natriuretic peptide, which functions to reduce blood volume, pressure, and Na⁺concentration. The gastrointestinal tract produces various hormones that aid in digestion. The kidneys produce erythropoietin. The thymus produces hormones that aid in the development of the immune system. The gonads produce steroid hormones, including testosterone in males and estrogen and progesterone in females. Adipose tissue produces leptin, which promotes satiety signals in the brain.

Art Connections

Figure \(\PageIndex{2}\): Goiter, a disease caused by iodine deficiency, results in the inability of the thyroid gland to form T₃ and T₄. The body typically attempts to compensate by producing greater amounts of TSH. Which of the following symptoms would you expect goiter to cause?

A. Hypothyroidism, resulting in weight gain, cold sensitivity, and reduced mental activity.
B. Hyperthyroidism, resulting in weight loss, profuse sweating and increased heart rate.
C. Hyperthyroidism, resulting in weight gain, cold sensitivity, and reduced mental activity.
D. Hypothyroidism, resulting in weight loss, profuse sweating and increased heart rate.

Answer

A

Glossary

adrenal gland

the endocrine gland associated with the kidneys

down-regulation

a decrease in the number of hormone receptors in response to increased hormone levels

endocrine gland

the gland that secretes hormones into the surrounding interstitial fluid, which then diffuse into blood and are carried to various organs and tissues within the body

exocrine gland

the gland that secretes chemicals through ducts that lead to skin surfaces, body cavities, and organ cavities.

hormone

a chemical released by cells in one area of the body that affects cells in other parts of the body

intracellular hormone receptor

a hormone receptor in the cytoplasm or nucleus of a cell

pancreas

the organ located between the stomach and the small intestine that contains exocrine and endocrine cells

parathyroid gland

the gland located on the surface of the thyroid that produces parathyroid hormone

pituitary gland

the endocrine gland located at the base of the brain composed of an anterior and posterior region; also called hypophysis

thymus

the gland located behind the sternum that produces thymosin hormones that contribute to the development of the immune system

thyroid gland

an endocrine gland located in the neck that produces thyroid hormones thyroxine and triiodothyronine

up-regulation

an increase in the number of hormone receptors in response to increased hormone levels

Contributors and Attributions

Organs with Secondary Endocrine Functions & Hormone Production

Skin

Keratinocytes in the epidermis of the skin use energy from the sun’s UV rays to convert a cholesterol-like steroid into the inactive form of vitamin D3, cholecalciferol. Cholecalciferol then enters the blood and reaches the liver and consequently the kidneys, where it is converted into the active form of Vitamin D, calcitriol.

Liver

The liver secretes several hormones and hormone precursors that have various effects throughout the body. It converts cholecalciferol from the skin into calcidiol. The final step for Vitamin D3 synthesis will take place in the kidneys. The liver also secretes angiotensinogen, which is the precursor for angiotensin II, a regulator for blood pressure. It also produces thrombopoietin, a hormone that stimulates platelet production. Along with the kidneys, the liver also produces 15% of the body’s erythropoietin (EPO), a hormone that stimulates red blood cell (erythrocyte) production. In addition, the liver also produces insulin-like growth factor I (IGF-I), which regulates the action of growth hormone that stimulates growth. Finally, hepcidin is also released to inhibit intestinal absorption of iron that helps regulate iron homeostasis and prevents iron overload.

Kidneys

The kidneys carry out endocrine roles by releasing three hormones. First, they convert calcidiol from the liver into calcitriol, the active form of Vitamin D3. Calcitriol is a hormone that helps enhance calcium absorption by the intestines to increase serum calcium concentrations. Second, the kidneys also release 85% of the body’s erythropoietin that stimulates red blood cell production. Third, the kidneys produce renin in response to dehydration or a drop in the body’s blood pressure. Renin converts angiotensinogen from the liver into angiotensin I. Angiotensin I is then converted to angiotensin II, which stimulates aldosterone release from the adrenal cortex. This pathway promotes sodium and water absorption by the kidneys, which ultimately increases blood pressure.

Heart

Increasing blood pressure stretches the heart wall and stimulates the atria to produce a hormone called Atrial Natriuretic Peptide (ANP). To maintain blood pressure homeostasis, ANP promotes sodium excretion by the kidney as well as an increase in urine output. This opposes the effects of angiotensin II and results in a decrease in blood pressure.

Stomach and Intestines

The stomach and intestines make up the largest endocrine network because they release multiple hormones that coordinate functions such as feeding, digestion, gastrointestinal motility, and secretion. One such hormone, Peptide YY signals a satiety signal that stops eating, whereas ghrelin is a hormone that is released when the stomach is empty to stimulate the appetite. It also stimulates the secretion of growth hormone release. Gastrin is another hormone that is released in response to food in the stomach to stimulate hydrochloric acid release. Cholecystokinin (CCK) is another hormone released by the small intestine in response to fats and stimulates the release of enzymes from the pancreas and bile from the gall bladder. Bile functions to emulsify fats to increase their surface area by grouping them into small clusters. This process makes it easier for lipase enzymes to break them down. CCK also has an appetite-suppressing effect.

Adipose Tissue

Adipose or fatty tissue produces at least three hormones that function in carbohydrate and lipid metabolism. Perhaps the most common hormone is leptin. Leptin is released by fat cells in response to food intake and produces a feeling of satiety after a meal. High levels of leptin tend to suppress the appetite, whereas a leptin deficiency increases appetite and food intake. Leptin also acts as a signal for the onset of puberty.

Osseous/Bone Tissue

Osteoblasts are bone cells that promote bone formation. They also play an endocrine role in producing the hormone osteocalcin, which stimulates beta cells in the pancreas to increase insulin production. This means that osseous tissue plays a role in glucose metabolism and the regulation of blood levels of glucose.

Lesson Summary

This lesson explores the various organs and tissues in the body that carry out an endocrine function by producing hormones or hormone precursors. For example, the skin begins the process of vitamin D synthesis by producing cholecalciferol. With the help of the liver and kidneys, cholecalciferol is converted into calcitriol, a hormone that regulates blood levels of calcium. Additionally, the liver and kidneys synthesize other hormones that play various roles throughout the body. One example is erythropoietin that stimulates red blood cell production. Both the liver and kidneys also play a role in blood pressure regulation (angiotensinogen produced by the liver and renin produced by the kidneys both increase blood pressure). Blood pressure is also regulated by a hormone released by the heart, Atrial Natriuretic Peptide (ANP), which decreases blood pressure.

The gastrointestinal tract also plays a major role in releasing hormones that influence feeding, satiety, and gastrointestinal motility. Peptide YY signals satiety whereas ghrelin stimulates appetite. Leptin is another hormone that limits appetite, secreted by adipose tissue. Finally, osseous tissue can also secrete the hormone osteocalcin, which plays a role in blood glucose metabolism by stimulating the production of insulin by the pancreatic beta cells.

Enteric Endocrine System

The Enteric Endocrine System

The second of the two systems that control digestive function is the endocrine system, which regulates function by secreting hormones. Recall that hormones are chemical messengers secreted into blood that modify the physiology of target cells. A target cell for a particular hormone is a cell that has receptors for that hormone and can thus respond to it.

Digestive function is affected by hormones produced in many endocrine glands, but the most profound control is exerted by hormones produced within the gastrointestinal tract. The gastrointestinal tract is the largest endocrine organ in the body and the endocrine cells within it are referred to collectively as the enteric endocrine system. Three of the best-studied enteric hormones are:

• Gastrin: Secreted from the stomach and plays an important role in control of gastric acid secretion.
• Cholecystokinin: A small intestinal hormone that stimulates secretion of pancreatic enzymes and bile.
• Secretin: Another hormone secreted from small intestinal epithelial cells; stimulates secretion of a bicarbonate-rich fluids from the pancreas and liver.

In contrast to endocrine glands like the anterior pituitary gland, in which essentially all cells produce hormones, the enteric endocrine system is diffuse: single hormone-secreting cells are scattered among other types of epithelial cells in the mucosa of the stomach and small intestine.

For example, most of the epithelial cells in the stomach are dedicated to secreting mucus, hydrochloric acid or a proenzyme called pepsinogen into the lumen of the stomach. Scattered among these secretory epithelial cells are G cells, which are endocrine cells that synthesize and secrete the hormone gastrin. Being a hormone, gastrin is secreted into blood, not into the lumen of the stomach. Similarly, other hormones produced by the enteric endocrine system are synthesized and secreted by cells within the epithelium of the small intestine.

Like all endocrine cells, cells in enteric endocrine system do not simply secrete their hormone continuously, which would not be very useful as a control system. Rather, they secrete hormones in response to fairly specific stimuli and stop secreting their hormone when those stimuli are no longer present. What stimulates the endocrinocytes in the enteric endocrine system? As you might deduce, in most cases these endocrine cells respond to changes in the environment within the lumen of the digestive tube. Because these cells are part of the epithelium, their apical border is in contact with the contents of the lumen, which allows them to continually “taste” or sample the lumenal environment and respond appropriately.

To illustrate how control is implemented through the enteric endocrine system, consider the important example of preventing stomach acid from burning the epithelium of the small intestine:

• Acid-laden ingesta flows out of the stomach, into the small intestine.
• Acid in the small intestine stimulates secretion of the hormone secretin from endocrine cells in the intestinal epithelium.
• Secretin stimulates the pancreas to dump a bicarbonate-rich fluid into the lumen of the intestine.
• The bicarbonate neutralizes acid, which removes the stimulus for secretion of additional secretion.
• In the absense of a secretin stimulus, the pancreas stops secreting bicarbonate.

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Endocrine System | ENT 425 – General Entomology

A hormone is a chemical signal sent from cells in one part of an organism to cells in another part (or parts) of the same individual.   They are often regarded as chemical messengers. Although typically produced in very small quantities, hormones may cause profound changes in their target cells.   Their effect may be stimulatory or inhibitory.   In some cases, a single hormone may have multiple targets and cause different effects in each target.   There are at least four categories of hormone-producing cells in an insect’s body:

1. Endocrine glands — secretory structures adapted exclusively for producing hormones and releasing them into the circulatory system.
2. Neurohemal organs — similar to glands, but they store their secretory product in a special chamber until stimulated to release it by a signal from the nervous system (or another hormone).
3. Neurosecretory cells — specialized nerve cells (neurons) that respond to stimulation by producing and secreting specific chemical messengers.   Functionally, they serve as a link between the nervous system and the endocrine system
4. Internal organs — hormone-producing cells are associated with numerous organs of the body, including the ovaries and testes, the fat body, and parts of the digestive system.

Together, these hormone-secreting structures form an endocrine system that helps maintain homeostasis, coordinate behavior, and regulate growth, development, and other physiological activities.

In insects, the largest and most obvious endocrine glands are found in the prothorax, just behind the head.   These prothoracic glands manufacture ecdysteroids, a group of closely-related steroid hormones (including ecdysone) that stimulate synthesis of chitin and protein in epidermal cells and trigger a cascade of physiological events that culminates in molting.   For this reason, the ecdysteroids are often called “molting hormones”.   Once an insect reaches the adult stage, its prothoracic glands atrophy (wither away) and it will never molt again.

Prothoracic glands produce and release ecdysteroids only after they have been stimulated by another chemical messenger, prothoracicotropic hormone (PTTH for short).   This compound is a peptide hormone secreted by the corpora cardiaca, a pair of neurohemal organs located on the walls of the aorta just behind the brain.   The corpora cardiaca release their store of PTTH only after they receive a signal from neurosecretory cells in the brain.   In a sense, they act as signal amplifiers — sending out a big pulse of hormone to the body in response to a small message from the brain.

14.1 An Overview of the Endocrine System – Fundamentals of Anatomy and Physiology

By the end of this section, you will be able to:

• Distinguish the types of intercellular communication, their importance, mechanisms and effects
• Identify the major organs and tissues of the endocrine system and their location in the body

Communication is a process in which a sender transmits signals to one or more receivers to control and coordinate actions. In the human body, two major organ systems participate in relatively “long distance” communication: the nervous system and the endocrine system. Together, these two systems are primarily responsible for maintaining homeostasis in the body.

Neural and Endocrine Signalling

The nervous system uses two types of intercellular communication—electrical and chemical signalling—either by the direct action of an electrical potential, or in the latter case, through the action of chemical neurotransmitters such as serotonin or noradrenaline. Neurotransmitters act locally and rapidly. When an electrical signal in the form of an action potential arrives at the synaptic terminal, they diffuse across the synaptic cleft (the gap between a sending neuron and a receiving neuron or muscle cell). Once the neurotransmitters interact (bind) with receptors on the receiving (post-synaptic) cell, the receptor stimulation is transduced into a response such as continued electrical signalling or modification of cellular response. The target cell responds within milliseconds of receiving the chemical “message”; this response then ceases very quickly once the neural signalling ends. In this way, neural communication enables body functions that involve quick, brief actions, such as movement, sensation, and cognition. In contrast, the endocrine system uses just one method of communication: chemical signalling. These signals are sent by the endocrine organs, which secrete chemicals—the hormone—into the extracellular fluid. Hormones are transported primarily via the bloodstream throughout the body, where they bind to receptors on target cells, inducing a characteristic response. As a result, endocrine signalling requires more time than neural signalling to prompt a response in target cells, though the precise amount of time varies with different hormones. For example, the hormones released when you are confronted with a dangerous or frightening situation, called the fight-or-flight response, occur by the release of adrenal hormones—adrenaline and noradrenaline—within seconds. In contrast, it may take up to 48 hours for target cells to respond to certain reproductive hormones.

In addition, endocrine signalling is typically less specific than neural signalling. The same hormone may play a role in a variety of different physiological processes depending on the target cells involved, for example, the hormone oxytocin promotes uterine contractions in women in labour and it is also important in breastfeeding and may be involved in the sexual response and in feelings of emotional attachment in both males and females.

In general, the nervous system involves quick responses to rapid changes in the external environment, and the endocrine system is usually slower acting—taking care of the internal environment of the body, maintaining homeostasis, and controlling reproduction (Table 14.1.1). So how does the fight-or-flight response that was mentioned earlier happen so quickly if hormones are usually slower acting? It is because the two systems are connected. It is the fast action of the nervous system in response to the danger in the environment that stimulates the adrenal glands to secrete their hormones. As a result, the nervous system can cause rapid endocrine responses to keep up with sudden changes in both the external and internal environments when necessary.

Table 14.1.1. Endocrine and nervous systems

Structures of the Endocrine System

The endocrine system consists of cells, tissues and organs that secrete hormones as a primary or secondary function. The endocrine gland is the major player in this system. The primary function of these ductless glands is to secrete their hormones directly into the surrounding fluid. The interstitial fluid and the blood vessels then transport the hormones throughout the body. The endocrine system includes the pituitary, thyroid, parathyroid, adrenal and pineal glands (Figure 14.1.1). Some of these glands have both endocrine and non-endocrine (exocrine) functions, for example, the pancreas contains cells that function in digestion as well as cells that secrete the hormones insulin and glucagon, which regulate blood glucose levels. The hypothalamus, thymus, heart, kidneys, stomach, small intestine, liver, skin, female ovaries and male testes are other organs that contain cells with endocrine function. Additionally, adipose tissue has long been known to produce hormones and recent research has shown that even bone tissue has endocrine functions.

Figure 14.1.1. Endocrine system. Endocrine glands and cells are located throughout the body and play an important role in homeostasis.

The ductless endocrine glands are not to be confused with the body’s exocrine system, whose glands release their secretions through ducts. Examples of exocrine glands include the sebaceous and sweat glands of the skin. As just noted, the pancreas also has an exocrine function: most of its cells secrete pancreatic secretion through the pancreatic and accessory ducts to the lumen of the small intestine.

Other Types of Chemical Signalling

In endocrine signalling, hormones secreted into the extracellular fluid diffuse into the blood or lymph and can then travel great distances throughout the body. In contrast, autocrine signalling takes place within the same cell. An autocrine (auto- = “self”) is a chemical that elicits a response in the same cell that secreted it. Interleukin-1, or IL-1, is a signalling molecule that plays an important role in inflammatory response. The cells that secrete IL-1 have receptors on their cell surface that bind these molecules, resulting in autocrine signalling.

Local intercellular communication is the province of the paracrine, also called a paracrine factor, which is a chemical that induces a response in neighbouring cells. Although paracrines may enter the bloodstream, their concentration is generally too low to elicit a response from distant tissues. A familiar example to those with asthma is histamine, a paracrine that is released by immune cells in the bronchial tree. Histamine causes the smooth muscle cells of the bronchi to constrict, narrowing the airways. Another example is the neurotransmitters of the nervous system, which act only locally within the synaptic cleft.

Career Connections

Endocrinologist

Endocrinology is a specialty in the field of medicine that focuses on the treatment of endocrine system disorders. Endocrinologists—medical doctors who specialise in this field—are experts in treating diseases associated with hormonal systems, ranging from thyroid disease to diabetes mellitus. Endocrine surgeons treat endocrine disease through the removal, or resection, of the affected endocrine gland.

Patients who are referred to endocrinologists may have signs and symptoms or blood test results that suggest excessive or impaired functioning of an endocrine gland or endocrine cells. The endocrinologist may order additional blood tests to determine whether the patient’s hormonal levels are abnormal, or they may stimulate or suppress the function of the suspect endocrine gland and then have blood taken for analysis. Treatment varies according to the diagnosis. Some endocrine disorders, such as type 2 diabetes, may respond to lifestyle changes such as modest weight loss, adoption of a healthy diet, and regular physical activity. Other disorders may require medication, such as hormone replacement, and routine monitoring by the endocrinologist. These include disorders of the pituitary gland that can affect growth and disorders of the thyroid gland that can result in a variety of metabolic problems.

Some patients experience health problems as a result of the normal decline in hormones that can accompany ageing. These patients can consult with an endocrinologist to weigh the risks and benefits of hormone replacement therapy intended to boost their natural levels of reproductive hormones.

In addition to treating patients, endocrinologists may be involved in research to improve the understanding of endocrine system disorders and develop new treatments for these diseases.

The endocrine system consists of cells, tissues and organs that secrete hormones critical to homeostasis. The body coordinates its functions through two major types of communication: neural and endocrine. Neural communication includes both electrical and chemical signalling between neurons and target cells. Endocrine communication involves chemical signalling via the release of hormones into the extracellular fluid. From there, hormones diffuse into the bloodstream and may travel to distant body regions, where they elicit a response in target cells. Endocrine glands are ductless glands that secrete hormones. Many organs of the body with other primary functions—such as the heart, stomach, and kidneys—also have hormone-secreting cells.

Click the drop down below to review the terms learned from this chapter.

Surgery of the endocrine system – search for specialists and doctors

What is Endocrine Surgery?

Endocrine surgery is a type of visceral surgery and is associated with the surgical treatment of endocrine disorders. “Endocrine” means “inward” where the secretion of hormones by the glands is clearly restricted by the bloodstream. These hormone-producing glands are called endocrine organs and include:

• thyroid gland
• parathyroid gland
• adrenal glands
• the endocrine part of the pancreas (the so-called Langerhans cells)
• diffuse neuroendocrine system.

Surgery of the pituitary and hormone-producing glands – the ovaries in women and the testes in men – however, falls into the field of neurosurgery and gynecology or urology.

What diseases do endocrinologists treat?

The thyroid gland is a purely endocrine organ and is located under the larynx on the thyroid cartilage. The main function of the thyroid gland is to store iodine and form the hormones triiodothyronine, thyroxine and calcitonin. Thyroid surgery is one of the four most common visceral surgery procedures, along with gallbladder, cecum, and inguinal hernia surgery.The following diseases most often require surgical treatment:

• Basedow’s disease
• Thyroid cancer
• Recurrent goiter (repeated)
• MEN syndromes (multiple endocrine neoplasia)

The four human parathyroid glands are located at the upper and lower poles of the thyroid gland and synthesize parathyroid hormone. Parathyroid hormone is an important regulator of calcium metabolism in the body.The parathyroid glands are operated on for the following diseases:

• primary hyperparathyroidism
• secondary hyperparathyroidism
• recurrent or persistent hyperparathyroidism
• primary hyperparathyroidism in MEN syndromes

The adrenal glands are located at the upper poles of the kidneys and produce hormones that regulate the balance of water, sugar, and minerals. The adrenal glands are composed of the cortex, which produces the aforementioned hormones, and the medulla, which produces adrenaline and norepinephrine.Operations are performed for the following diseases:

• Conn’s syndrome (benign tumors of the adrenal cortex)
• Itsenko-Cushing’s syndrome (tumor of one adrenal gland or bilateral hyperplasia)
• Pheochromocytoma (unilateral or bilateral adrenal medullary tumor)
• Incidentaloma (adrenal hormonal tumor)

What surgical methods are there?

If possible, surgical interventions in the endocrine organs are carried out minimally invasive, using the so-called “keyhole” method.At the same time, small punctures are performed and operated with a mini-camera and special thin instruments, thereby rejecting a large incision. The advantages of this method are reduced wound pain, reduced blood loss, faster recovery and early discharge from the hospital, fewer complications in wound healing and scarring, and improved cosmetic results.

Which doctors and clinics are specialists in endocrine surgery?

Endocrine surgery is a type of visceral surgery.It is represented in all hospitals and specialized surgical clinics. However, patients are treated not only by surgeons, but also by an interdisciplinary team of doctors.

An endocrinologist plays a special role in the diagnosis of a disease. If the change in the endocrine organ is caused by a tumor, doctors from other disciplines are involved in the treatment process. Every week, cases of cancer patients are discussed at councils where endocrinologists, radiologists, nuclear medicine specialists, oncologists, gastroenterologists and surgeons gather, who jointly develop a treatment concept.

We will help you find a specialist in the treatment of your disease. All of the listed doctors and clinics have been checked by us for their high professionalism in the field of endocrine surgery. They are waiting for your questions and wishes regarding treatment.

Sources:

• Bleese and Mommsen, Short Course in Surgery, 2010, Thieme (Bleese und Mommsen, Kurzlehrbuch Chirurgie, 2010, Thieme)
• Hermann, Endocrinology for the clinic: diagnosis and therapy A-Z, 2014, Thieme (Herrmann, Endokrinologie für die Praxis: Diagnostik und Therapie von A-Z, 2014, Thieme)

Biohackers believe that hormones prolong youth.What does science say?

Hormones are biohackers’ best friends. For example, entrepreneur Sergei Fage, the most famous Russian biohacker, injects himself with the growth hormone somatropin, drinks micro doses of thyroid hormones and blocks his estrogen receptors in order to “increase testosterone production.” Is it safe? The endocrinologist, the author of the telegram channel “Endonovsti” Evdokia Tsvetkova, told our friends from the publication Reminder about this.

Anastasia Dulgier / Unsplash

Where do hormones and hormonal disruptions come from

The human body is a huge plant with billions of cells that produce hormones.Each hormone released does not work in one position – it plays different roles in different parts of the body. Take insulin for example: it increases the penetration of glucose into cells, stimulates the formation of glycogen from glucose in the liver and muscles, enhances the synthesis of fats and proteins, promotes the transport of potassium ions into cells, inhibits the activity of enzymes that break down glycogen and fats, and so on. That is why hormonal self-medication is so dangerous – the consequences can affect a large number of systems and organs.

The process of hormonal regulation can be called a hormonal swing, on which we gently swing for most of our life. The secretion of hormones into the blood has peaks and troughs that repeat from day to day with slight variations. This is because the physiological processes in the human body are synchronized with the rotation of the Earth around its axis – this is called circadian rhythms. For example, in the morning, a healthy person has a peak in the production of the glucocorticosteroid cortisol – this helps to wake up, cheer up and start a new day.By the evening, cortisol production decreases – it’s time to relax and get ready for bed. This system of hormonal regulation is called impulse secretion. Such a “hormonal swing” is a dynamic self-regulating system, and if everything is in order, then the hormones are produced as much as the body needs.

But what if hormones are not produced enough or excessively? There could be two reasons.

Perhaps somewhere in the endocrine system there was a “breakdown” – and then an endocrine disease develops.But in addition to diseases, there are some conditions in which the amount of hormones also changes. One of them is aging, a process that happens to all of us constantly, from the moment of birth. Aging begins to affect hormones almost immediately after leaving puberty: after a period of adolescent “hormonal surge” and relatively short stabilization, the secretion of hormones gradually begins to decline. The synthesis of sex hormones, growth hormone and melatonin decreases especially actively with age.In this regard, a new medical direction has appeared – anti-aging medicine, in the arsenal of which, among other things, there is also hormonal therapy.

Hormone therapy in general is the intake of synthetic hormones for the treatment or prevention of any disease, as well as, for example, for contraception. In particular, hormone therapy can be used when the body’s own cells do not produce enough hormones – and their shortage needs to be replenished with the help of medications.

Hormones are substances that are produced in the endocrine glands, or endocrine glands.The endocrine glands include the thyroid and pancreas, the adrenal glands, the gonads – the testes or ovaries, the parathyroid glands, as well as certain areas in the brain – the pineal gland and the hypothalamic-pituitary complex.

But that’s not all. Throughout the body are distributed numerous specialized cells that produce hormones – apudocytes. They capture amino acids and produce some hormones from them – in particular, adrenaline, norepinephrine, dopamine, and serotonin. More than 60 types of such cells have now been identified, they are located in a wide variety of organs and tissues – including the gastrointestinal tract, organs of the urinary and respiratory systems, skin and adipose tissue.

How hormones began to be used to prolong youth

Ideas of prolongation of life and youth with the help of hormones – namely, transplantation of the sex glands – appeared at the dawn of the development of endocrinology as a science.

First, the German physiologist Adolf Berthold in 1849 noticed that when a castrated rooster is transplanted into the abdominal cavity of the testes of another rooster, all external effects of castration disappear in the first: the missing lush comb and beard are restored, the drooping fan of tail feathers reappears (whereas usually a castrated rooster with time outwardly becomes more and more like a chicken).

Forty years later, in 1889, at a meeting of the Paris Biological Society, Professor of Experimental Biology Charles Brown-Séquard made a startling report about experiments carried out on himself. The seventy-two-year-old scientist injected himself with extracts from the seminal glands of animals – and found that they have a “rejuvenating” effect on the aging organism. He had a feeling of extraordinary vigor, increased efficiency, muscle strength and libido. Brown-Sekar called the extracts from the testes “the elixir of youth.”The press raised a huge fuss about this event, pharmacies began to sell “Brown-Sekar’s liquid”, for which queues of people hungry for rejuvenation lined up. Alas, Brown-Séquard did not manage to rid the world of old age: the rejuvenating effect was short-lived, and after two or three months, age-related changes even progressed. Nevertheless, this was the first step towards modern anti-aging medicine and hormone therapy.

Antiage medicine, or medicine of active aging, has experienced its new birth relatively recently.In 1993, osteopaths Robert M. Goldman and Ronald Klatz founded the American Academy of Anti-Aging Medicine, which certifies active aging professionals. Anti-aging medicine strives to achieve and maintain good health regardless of chronological age. Sounds great, doesn’t it?

After all, if the natural mechanisms of aging can [1, 2] lead to the development of diseases (cardiovascular, oncological, osteoarticular, neurodegenerative and diabetes mellitus), then would it not be correct with all the forces and achievements of science to prevent it? This is certainly true.

But it is worth noting that not all the ideas of the American Academy of Antiage Medicine correspond to the provisions of evidence-based medicine: in particular, attempts to use growth hormone, a number of antioxidants, and sex hormones for anti-aging purposes are controversial and unsafe without taking into account indications and contraindications. The American Medical Association does not recognize this organization at all. Scientists who have been dealing with aging issues for a long time have already criticized anti-aging medicine, contrasting it with gerontology – a science that studies the biological, social and psychological aspects of human aging, its causes and ways of dealing with it.That is, doing all the same, but using only methods with proven scientific effectiveness and safety.

We will focus on those anti-aging hormone therapy methods that are at the intersection of anti-aging medicine and gerontology – and have an evidence base.

What is the difference between a hormonal preparation synthesized in a laboratory and a hormone produced by our body?

Most of the hormones used in medical practice differ from those synthesized by our body, or endogenous hormones.

The difference most often lies in the fact that in an artificially synthesized drug there are additional molecules that can:

• prolong the effect of the drug in comparison with the endogenous hormone, thereby lengthening the interval between its intake / injections for greater human comfort;
• accelerate / enhance the effect of the drug in comparison with the endogenous hormone, thereby shortening the waiting period for the effect, reducing the dose necessary to achieve the desired effect;
• increase the selectivity of the drug, thereby reducing the likelihood of side effects.

In addition, drugs containing hormones have excipients that provide a specific method of delivery: subcutaneous injections, gels, creams, patches.

In some cases, hormonal drugs may even have an advantage over our body’s hormones. In particular, oral contraceptives containing droperinone, a synthetic analogue of the hormone progesterone, are used in the treatment of premenstrual syndrome, which can develop against the background of natural fluctuations in estrogen and progesterone in the body.

Menopausal hormone therapy (MHT)

Estrogens and progestogens, the so-called “female” sex hormones, are present in all people, it is just that women have more of them in their bodies than men. Sex hormone levels fluctuate throughout a person’s life. Factors that can affect female sex hormone levels include age, phase of the menstrual cycle, pregnancy, stress, medication, environment, and menopause.

“Female” sex hormones are involved in puberty and sexual development, protective inflammatory reactions of the body, affect the ability to get pregnant, sexual desire, regulate the growth of bones and muscles, cholesterol levels, distribution of fat in the body, stimulate hair growth.

After the peak of secretion of sex hormones in puberty – from 8-10 to 13-15 years – the level of “female” hormones stabilizes, a plateau sets in. Then, in perimenopause – 41–51 years, – the secretion of estrogen and progesterone begins to decline.A sharp decline occurs in menopause and postmenopause (45–65 years), and the level remains stably low after 65 years.

If menstruation stops before the age of 40, then they talk about premature menopause, before 45 – about early. Unfortunately, there is no serious prevention of early menopause. After all, one of its reasons is a genetic predisposition: if a woman’s mother and grandmother had early menopause, then, most likely, she will also have it. But now there is information that some changes in diet can slightly delay the onset of menopause: high consumption of oily fish – by 3.3 years, legumes – by about a year.But the abuse of refined pasta and rice, on the contrary, can bring menopause closer by 1.5 years.

What symptoms will help to suspect that you have decreased levels of “female” sex hormones?

• You have noticed a violation of the menstrual cycle.
• You have hot flashes interspersed with chills and intense sweating.
• You are suffering from mood swings, depression has appeared.
• Pain in joints and muscles appeared or increased.
• You notice vaginal dryness and pain or discomfort when having sex.
• You have decreased libido.
• You have more frequent urinary infections such as cystitis.

The beginning of MHT should fit into the “therapeutic window” – no more than 10 years from the end of menstruation. Therefore, it is worth carefully monitoring your cycle – and when (as a rule, at the age of over 40) it becomes very irregular or menstruation does not come for more than six months, it makes sense to contact a gynecologist-endocrinologist to confirm the onset of menopause. For this, a hormonal blood test is taken – for estradiol and follicle-stimulating hormone.Rapid menopause tests, similar to rapid pregnancy tests, are now on the market as well.

Low estrogen levels are a serious health risk. It causes a loss of bone mineral density – this can lead to osteoporosis and fractures of bones, including the neck of the femur, which can be disabling for a woman. Menopausal hormonal changes can also increase your risk of heart disease and stroke.

However, a woman’s life does not end with the end of the reproductive period.Due to the increase in life expectancy, a whole third of the life of a modern woman falls on menopause. And if menopause worsens the quality of this life, then menopausal hormone therapy (MHT) is the way out.

Possible bonuses of a properly selected MGT:

• reducing the risk of myocardial infarction, cardiovascular diseases, type 2 diabetes mellitus, prevention of atherosclerosis;
• reducing the risk of premature death;
• weakening of climacteric and urogenital manifestations;
• prevention of osteoporotic fractures;
• remission of depression;
• reduced risk of Alzheimer’s disease and dementia;
• improving the quality of night sleep;
• improving the quality of sexual life;
• skin aging regression;
• reduction of osteoarticular pain, improvement of joint flexibility and elasticity of ligaments.

And due to all of the above – a significant improvement in the quality of life and an increase in its duration.

Some drugs used for MHT may increase the risk of endometrial and breast cancer. Therefore, it is important to take hormone therapy only according to indications, to select drugs together with a doctor – and to receive the minimum effective dose of hormones. Also, while you are taking MHT, visit your doctor once a year for a checkup. To minimize the risks, therapy should be part of an overall strategy that includes a healthy diet – less red and processed meats, sweets, more fish – at least 150 minutes of physical activity per week, quitting smoking and drinking alcohol.

Not only in women, but also in men, there may be a lack of progesterone and estrogen.

Estrogen deficiency in the male body is still poorly understood and, as a rule, is associated with certain genetic “breakdowns”. Currently, estrogens are not prescribed for men, except for the treatment of rare diseases such as congenital estrogen deficiency.

Progesterone deficiency in men most often develops during andropause – this is analogous to menopause in men. This is due to the fact that the ratio of testosterone and estrogen changes – and because of this, the synthesis of progesterone is blocked.In this case, the question of hormone therapy with testosterone is resolved.

Andropausal hormone therapy (AGT)

Testosterone belongs to a group of hormones that everyone has, but in men they are produced in greater quantities – because of this they are called androgens, or “male” sex hormones.

Androgens have many functions: they stimulate metabolism, cell renewal, muscle growth, and increase bone mineral density. They also affect more obvious things: the size of the external genital organs (both the penis and testicles, and, for example, the clitoris), sperm synthesis, the timbre of the voice, the growth of facial hair and in certain areas of the body.In addition, these hormones affect the formation of a conditionally male constitution of the body – this is a greater length of the arms in relation to the length of the legs, a wider chest and narrow pelvis, a characteristic distribution of fat and muscles.

During puberty, testosterone levels in boys increase significantly, and after thirty they begin to gradually (by 1–2% per year) decline. At the age of 55-60, it becomes already 20-25% less, and the so-called andropause sets in – from that moment low testosterone is considered to be the norm.True, unlike postmenopausal women, the maturation of sex cells in men after andropause does not stop.

The lack of testosterone in men is called “hypogonadism”. At working age, it occurs, according to various sources, with a frequency of 8.6 to 38.7%. The reasons can be very different – for example, the work of Leydig cells, synthesizing this hormone, can be disrupted by trauma, infection, exposure to radiation or chemotherapy, with testicular tumors, and some other diseases.There are diseases and medications that disrupt the hypothalamus or pituitary gland, which, in turn, stop stimulating the production of androgens.

A man’s testosterone deficiency may be somewhat reminiscent of menopause.

How to suspect you have a testosterone deficiency?

• Reduces body and facial hair.
• You begin to lose muscle mass.
• Decreased libido, erectile dysfunction may appear.
• The sperm count decreases, and in connection with this, infertility may develop.
• Breast enlargement according to the “female” type.
• Hot flushes appear.
• You become irritable, easily lose concentration, and may even become depressed.

If you have these symptoms, you can take a blood test for total testosterone and see an endocrinologist. You do not need to regularly check your testosterone levels “just in case”.

As such, there is no prevention of age-related hypogonadism, but one risk factor can be influenced – fat mass.In adipose tissue, testosterone is converted to estrogens, respectively, more adipose tissue – more estrogen and less testosterone. To prevent this from happening, it makes sense to maintain a stable body weight within a healthy BMI.

Andropause, or age-related hypogonadism, is considered a natural process, but it can affect quality of life. Therefore, hormonal therapy for age-related changes in men is now actively discussed. It makes sense for Russian men to think about it at about 50–55 years old – of course, if the symptoms of hypogonadism did not begin to appear at an earlier age.

Andropausal hormone therapy is not always safe: for example, patients with certain prostate diseases, heart failure and obstructive sleep apnea should not receive testosterone. In 2013–2014, a link was reported between this therapy and an increase in the incidence of myocardial infarction and stroke, and the FDA issued a cautionary bulletin.

Possible bonuses of a properly selected AGT:

• increased libido, more frequent and prolonged erections;
• increase in muscle mass and strength;
• reduction in the volume of adipose tissue;
• normalization of blood pressure and cholesterol values;
• increased vigor.

Women also have a testosterone deficiency, for example, with diseases of the pituitary gland or adrenal glands. At the same time, there is a decrease in libido, vaginal dryness, impaired attention, or even depression. Osteoporosis and menstrual irregularities can also develop. The official indication for testosterone in women is hypoactive sex drive disorder, in which a woman’s interest in sex decreases.

Studies have been conducted that have shown good efficacy of topical testosterone for vulvovaginal atrophy in menopause, but so far such treatment is not standard.

Melatonin: The Key to Longer Life?

Melatonin, the so-called “sleep hormone”, does not just help us fall asleep – it is an important hormone for the body that has special antioxidant properties. In humans, the secretion of melatonin occurs both in apudocytes throughout the body, and in the brain, in a special endocrine gland – the pineal gland.

The synthesis of melatonin is controlled by sunlight. It is he who is the substance that synchronizes biological day and night with the day and night of the environment around us – a chronobiotic.

The production of melatonin occurs exclusively in the dark. Under artificial lighting at night, the synthesis of melatonin is inhibited. Your melatonin production may be disrupted if you look at 60 to 130 lux blue light sources (460-480 nm), such as laptop or smartphone screens, in the evening.

Melatonin not only realizes important antioxidant and chronobiotic functions for the body, but also affects carbohydrate metabolism, insulin secretion, adipose tissue hormones (leptin, adiponectin) and eating behavior.Due to its properties, melatonin regulates metabolism in almost every cell type.

Why can a lack of melatonin develop? There may be many reasons for this: the already mentioned excessive lighting at night, shift work, irradiation of the pineal gland, etc. But one of the reasons is also age-related changes in the body.

After the peak in prepubertal, the level of melatonin decreases to a stable “adult” level – this is when a person’s “biological clock” should stabilize.Melatonin is produced in the right amount and at the right time, a person begins to go to bed and get up at about the same time – in accordance with his chronotype (unless, of course, external circumstances such as work schedule interfere with him).

But in people over 25-40 years of age, the production of melatonin by the pineal gland decreases – to about 60% of the “adult” level. From this point on, there is a constant decrease in the level of the hormone, up to 20% of the “adult” level by the age of 90.

How do you know if your melatonin level can be lowered?

• You have difficulty falling asleep at night, often feel weak, tired, sleepy during the daytime.
• Your appetite increases.
• Eating disorders appear or worsen

In such a situation, it is necessary to consult a doctor – a somnologist or an endocrinologist, who will already recommend the necessary studies.

Decreased melatonin can reduce quality of life and is one of the risk factors for premature death. A lack of melatonin can lead to sleep disturbances, an increased risk of type 2 diabetes and cancer, mainly breast and prostate cancer.

Some of these manifestations can be reversed with melatonin therapy.

Potential bonuses of properly selected melatonin therapy:

• improving the quantity and quality of sleep;
• antioxidant effect, prevention of cancer;
• reduction in body fat.

But taking melatonin is not safe for everyone. Melatonin therapy should be considered with caution in the presence of epilepsy, autoimmune diseases, severe renal and hepatic insufficiency.

Are my adrenal glands tired?

In recent years, along with the hormones listed above, the so-called “adrenal fatigue syndrome” has begun to be recorded in the causes of aging in the body. At the same time, modern evidence-based medicine completely denies the existence of such a state.

According to the adherents of this theory, constant stress (accompanied by the production of hormones – especially cortisol) creates an excessive load on the adrenal glands – and the glands “burn out”.Lack of proper amounts of adrenal hormones, which supposedly occurs as a result, leads to the onset of many symptoms: fatigue, trouble falling asleep or waking up, and the need for stimulants such as caffeine to stay awake during the day.

Due to the fast pace of modern life, many people are under constant stress and are deprived of adequate sleep. It is easy to understand why people find their symptoms in Fatigue Adrenal Syndrome and are happy to begin treating the condition.But a systematic review published in 2016 in BMC Endocrine Disorders found no evidence that “adrenal fatigue” actually exists. Adrenal fatigue is not recognized by the Society of Endocrinologists or other endocrinological communities, in contrast to the real-life disease – adrenal insufficiency.

The most paradoxical thing is that “adrenal fatigue syndrome” in its symptoms is not even close to adrenal insufficiency.Primary adrenal insufficiency can develop as a result of an autoimmune or infectious disease, metastatic lesions of the adrenal glands, as well as due to their surgical removal. This condition is characterized by weight loss, joint pain, anorexia, nausea, vomiting, diarrhea, dry skin, low blood pressure, and fatigue. And, of course, this disease requires hormone therapy – glucocorticosteroids, mineralocorticosteroids, and sometimes androgens.

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Sanatorium “Dolina Narzanov” in Kislovodsk – official site

Kislovodsk is the southernmost resort town of the Caucasian Mineral Waters.Since ancient times, thanks to its mineral springs – the Kislovodsk narzans, as well as its curative microclimate, it is known as one of the best balneological resorts.

Sanatorium “Dolina Narzanov” is located in the center of Kislovodsk, just a 15-minute walk from the sanatorium are the best resort park in Europe and the Narzan Gallery, within walking distance – Zhelyabovsky spring, famous for its healing properties.
A health resort that meets all European standards is 4 bedroom buildings, 2 VIP-buildings, a health-improving building, 2 dietary restaurants, a sports-health-improving and cultural-entertainment center, a water park.

Guests are offered comfortable Suites, Apartments, Suites, single and double rooms. All the main buildings of the health resort are connected with each other by warm passages. Rooms are equipped with modern furniture, TV, refrigerator, telephone, safe, climate control systems, fire and burglar alarms.
The profile of the sanatorium is diseases of the circulatory system, respiration, digestion, nervous and endocrine systems, musculoskeletal system and connective tissue. The sanatorium is licensed for 35 types of medical activities.A wide range of spa services is carried out in a modern medical and diagnostic center, equipped with the most advanced diagnostic medical equipment manufactured by leading companies in the world. Complex treatment includes balneotherapy, all types of physiotherapy apparatus, reflexology, inhalations, paraffin wax therapy, mud therapy, underwater shower massage, all types of hydropathy, massage. There are offices for bioresonance computer therapy, computer vision correction, a halo and speleocomplex, a dental office, and an office for monitoring bowel cleaning.Relaxation capsules, body shaping rooms and a SPA center are very popular. Specialized health-improving programs are offered: “Antistress”,

“Men’s health”, “Women’s health”.
Meals are based on a seasonal customized menu system. The dietician of the sanatorium develops and compiles individual menus, taking into account the nutritional characteristics of each vacationer (vegetarianism, separate meals, meals according to “hemocode”, fasting). A children’s menu has been developed for children.The health resort offers a large assortment of fresh juices and soft drinks, meals according to individual menu orders, the bar “Kurortny Roman” is open. The phytobar offers guests the mineral water “Essentuki No. 4”, “Slavyanovskaya”, an oxygen cocktail and medicinal herbal teas.

Satellite TV, long distance and international telephone communications, open access WI-FI, ATM, pharmacy, convenience store, rental point, hairdresser, laundry, sewing workshop, guarded parking lot, children’s playroom and playground, library, conference room and auditorium.

You can relieve stress, become slimmer in the health resort complex, where there is a swimming pool with hydromassage facilities and a gym, exercise therapy room, sauna, Russian bath, solarium, tennis courts (indoor and outdoor), billiards. Walking along the famous “health paths” – park terrainkurs help to get rid of extra pounds. In summer, in the sanatorium “Narzanov Valley” the first and only water park on the Caucasian Mineral Waters plays with all the colors of the rainbow: waterfalls, cascades, exciting slides, jacuzzi, all kinds of entertainment for children.Excellent infrastructure and impeccable service will create a great mood for the whole family.

Various excursion programs are organized, which include more than 100 interesting routes in resort cities and their environs (Dombay, Elbrus region, Arkhyz, etc.)
The sanatorium has been awarded many awards, including gold medals of the Ministry of Health of the Russian Federation and Social Development in the nominations “Best technologies for treatment and recovery”, “Best SPA technologies”.

90,000 What does an osteopathic doctor treat United hospital with a polyclinic of the Administrative Department of the President of the Russian Federation

Osteopathy is a field of medicine based on a holistic concept aimed at diagnosing and treating dysfunctions of macro- and micromobility of body tissues.As part of traditional medicine, it takes into account the pathogenetic mechanisms of the development of diseases and considers the human body outside the nosological approach, restoring the ability for self-regulation and adaptation. For diagnostic and therapeutic manipulations in osteopathy, examination, functional tests, palpation and the impact of the doctor’s hands on the anatomical structures of the skull, sacrum, joints, muscle-fascial structures, internal organs of the patient’s body are used, taking into account the necessary research offered by modern medicine.Osteopathy is based on fundamental knowledge of anatomy and physiology, and the highest sensitivity of the hands of an osteopathic physician, achieved through years of special training. Mastering the specialty of an osteopathic physician requires additional fundamental four-year training.

Osteopathy effectively treats diseases:

Musculoskeletal system

• Posture disorders (posture disorders during pregnancy)
• Partial or complete loss of mobility as a result of trauma (adhesions, bruises, dislocations, fractures, fractures, ruptures, sprains)
• Soft tissue injuries
• Consequences of surgical operations
• Perinatal injuries of the newborn
• Partial or complete loss of joint mobility Partial blockade of one or more joints
• Arthrosis and non-infectious arthritis
• Temporomandibular joint dysfunctions calcaneal spur syndrome Pain in areas (cervicalgia, cervicobrachialgia, coccygodynia, coxalgia, cruralgia, dorsalgia, sciatica, lumbodynia, pain in the back of the head, podalgia, pubalgia, sacral pain, and lopalgia) 9000

Digestive system

• irritable bowel syndrome
• transit disorders (constipation and diarrhea)

Endocrine system

• locomotor and vascular disorders in diabetes
• locomotor disorders during menopause
• essential hypertension
• essential hyperthyroidism, hypothyroidism
• essential hyperprolactinemic syndrome

Reproductive and genitourinary system

• adhesions after adnexitis and childbirth
• testicular pain
• violations of the position and mobility of the uterus
• menstrual irregularities
• preparation for childbirth
• prostatitis
• premenstrual syndrome

Central nervous system disorders

• essential headache
• consequences of cranial trauma
• defeat of CHMN
• perinatal cerebral injury syndrome
• spasticity
• dizziness

Disorders of the peripheral nervous system. 1.Disorders of sensitivity (anesthesia, dysesthesia, paresthesia)

• Guyon’s canal syndrome
• tarsal canal syndrome (posterior tibial nerve)
• carpal tunnel syndrome (median nerve)
• scalene syndrome (brachial plexus)

Disorders of the peripheral nervous system. 2. Motor Disorders

• sympathicotonia
• Raynaud’s syndrome
• Herniated disc and protrusion, radiculitis, radiculopathy, dorsopathy

Disorders of the peripheral nervous system. 3. Psychosomatic Disorders

• asthenia
• essential headache
• enuresis
• functional painful
• essential vertigo syndrome

Respiratory organs

• bronchial asthma
• chronic bronchitis
• consequences of pleurisy
• consequences of pneumothorax
• rhinitis

Excretory system

• chronic cystitis
• urinary incontinence, enuresis
• primary renal failure
• renal lithiasis
• irritable bladder syndrome: nephroptosis, prolapse of the bladder

Dental system

• Temporomandibular joint disorders
• occlusion disorders associated with impaired posture and gait
• bruxism

Mastering the techniques of palpation, the doctor must learn a huge number of techniques for manual diagnosis and treatment, turning them into the art of therapeutic touch.

All manipulations are painless: during the session, the patient feels only pleasant relaxation throughout the body. The session lasts from 30 minutes to 2 hours.

An osteopathic doctor, examining the body with his hands, feels deviations from the norm: muscle and ligament tension, an increase in the size and density of the organ, displacement of bones, tension of the tendons and fascial membranes, disturbance of the rhythms of organ movement. The osteopath’s fingers register the slightest changes, even those that are not yet painful.

The task of the doctor is to find and eliminate the cause of the disease, and not its consequence, that is, to return the displaced organ, due to which the back hurts, to the correct position, or to relieve muscle tension that causes pain.In this case, all influences are performed only within the framework of the physiological capabilities of the body and do not exceed the pain threshold.

Osteopathy as a method of treatment has the following advantages:

• Accuracy of diagnostics. An osteopath is able to catch functional abnormalities that are not recorded even by diagnostic devices, and to identify the true cause of the disease, even if it is not where it hurts.
• Safe treatment without pain. Osteopathy uses gentle, completely safe and painless techniques.
• Eliminate the cause. The osteopath identifies the root causes of the development of the disease, which are often hidden behind neurological symptoms and radiating pain. This allows for effective treatment, and not just alleviate well-being.
• Scientific base. Osteopathy is based on precise knowledge of anatomy, physiology, biochemistry and histology.
• Reduction of medication intake. Successful use of osteopathy allows you to reduce the frequency and quantity of medications you take, or to stop taking medications altogether.

Endocrine glands, hormones | Internet edition “News of Medicine and Pharmacy”

Article published on p. 20-22 (World)

Until the middle of the 20th century, insufficient attention was paid to endocrinology. In medical institutes, if they studied it, then it was primitive.

Major scientific discoveries in medicine of the 20th century have changed the content, essence and tasks of endocrinology – the science of physiology and pathology of the endocrine glands.

Isolation of new hormones, receipt and use in medical practice of insulin (1921-1925), which saved the lives of many patients with diabetes mellitus, the successful introduction of hormonal drugs into medical practice in the treatment of many non-endocrine diseases (like the “era of antibiotics”), as well as the consequences of the Chernobyl disaster, when penetrating radiation caused damage primarily to the thyroid glands and other endocrine and non-endocrine organs, made endocrinology one of the most important branches of modern clinical medicine.

Institutes of endocrinology have been created, departments in many medical universities have been organized, relevant textbooks, thematic collections, teaching aids, journals have been published, articles and original reports in the periodical medical press are often published, international and republican conferences, congresses, symposia are regularly held, associations of endocrinologists have been formed at all levels, special academic tips.

Endocrinology (from the Greek. endo – inside, krino – to allocate, logos – teaching) is one of the youngest and most rapidly developing branches of medicine. In terms of general biological and general medical significance, it occupies an important place among other medical sciences.

Endocrinology is closely related to cardiology, oncology, gynecology, dermatology, and many other medical disciplines. Her problems, especially hormone therapy, affect to one degree or another all areas of medicine.It represents a large section of clinical medicine associated with the systemic regulation of the main processes of growth and development of the body.

The endocrine glands in the body are subordinate to the central nervous system and represent its most important humoral supplement.

The endocrine system is a complex of glands located in various parts of the body with a specific structure and secreting into the blood special substances – hormones (from the Greek. hormaon – I set in motion).

Hormones are biologically active substances formed in the endocrine glands and acting on organs and tissues remote from the place of their secretion, as well as metabolic processes. They are involved in the neurohumoral regulation of the body’s vital activity and affect, in essence, all types of metabolism.

Currently, it is reliably known about the presence of the following endocrine glands: pituitary gland, pineal gland (pineal gland), thyroid gland, parathyroid glands, thymus gland, pancreatic islets of Langerhans, adrenal glands (paired), male and female sex glands (paired).

It is also assumed the existence of endocrine formations in the liver, mucous membranes of the gastrointestinal tract, producing gastrin, pancreosimin and other hormones. The role of intestinal incretins in the regulation of carbohydrate metabolism has been proven: agonists of glucagon-like peptide I, inhibitors of dipeptidyl peptidase-4, the derivatives of which have been successfully used in the complex therapy of type 2 diabetes mellitus.

Closely adjacent to hormones is the spleen preparation obtained from the spleen, which is used for various intoxications, pregnancy toxicosis, etc.

The problem of finding new sources of hormone formation is at the stage of research and study.

For a description of the endocrine organs and the hormones secreted by them, see Fig. 1.

1. Pituitary gland

Located in the Turkish saddle of the main bone of the skull. Its weight is from 0.4 to 1 g. It consists of three lobes: anterior (glandular – adenohypophysis), intermediate and posterior (nervous), which is, as it were, a continuation of the interstitial brain.

The anterior lobe of the pituitary gland (makes up 75% of the mass of the gland) produces 7 hormones, 5 of them act through a tropic effect on other endocrine glands: thyroid-stimulating, corticotropic, follicle-stimulating, luteinizing and lactogenic.

Therefore, it is no coincidence that the pituitary gland is called the “conductor” of the endocrine system.

Growth hormone, or somatotropic hormone, as well as prolactin, are produced by eosinophilic cells (by the nature of the color of the preparations on the slide), and the rest of the hormones of the adenohypophysis are basophilic. There are also non-staining chromophobic cells that do not show signs of secretory activity under normal conditions.

Growth hormone acts directly on cells of various organs and tissues, affecting growth, metabolism, especially protein.Prolactin stimulates anabolic processes and, along with the lactogenic hormone, affects the development of the mammary glands and lactation.

Thyroid stimulating hormone promotes the formation of follicles in the thyroid gland and, accordingly, the synthesis of thyroxine and triiodothyronine. The corticotropic hormone activates the function of the adrenal cortex. Gonadotropic hormones (follicle-stimulating and luteinizing) exert their effect on the sex glands: follicle-stimulating hormones in women stimulate the growth of ovarian follicles, in men – the growth of the epithelium of the seminiferous tubules; luteinizing promotes ovulation and the development of the corpus luteum in the ovaries and activates the growth and function of Leydig cells in the testes.The lactogenic hormone stimulates the secretion of milk by the mammary glands.

The function of the pituitary gland is controlled by the hypothalamus. The existence of the hypothalamic-neurohypophyseal system has been proven, consisting of the supraoptic and paraventricular nuclei of the anterior hypothalamic region and the neurohypophysis. It is believed that these nuclei produce special substances, the so-called releasing factors (or releasing hormones), which stimulate the secretion of the corresponding tropic hormones.

The function of the intermediate lobe of the pituitary gland is not fully understood.The effect of its products (melanotropin) on the nature of skin pigmentation, appetite is assumed, the resulting substance adiposin affects fat metabolism.

In the extract of the posterior lobe of the pituitary gland, two active factors are found: vasopressin and oxytocin. Vasopressin (pitressin) has an antidiuretic effect: it reduces urine output by increasing the reabsorption of water from the glomerular filtrate in the distal parts of the convoluted tubules of the kidneys. In addition, vasopressin increases blood pressure by constricting arterioles and capillaries.

Oxytocin affects the tone of the smooth muscles of the intestines and uterus, promotes the activation of labor.

The place of formation of these factors has not yet been finally clarified. It is possible that they are formed in the supraoptic and paraventricular nuclei of the anterior hypothalamus, from where they enter the posterior lobe of the pituitary gland through the “funnel”.

2. Epiphysis

(pineal gland)

It refers like the posterior lobe of the pituitary gland to the interstitial brain, located on the median plane deep under the cerebral hemispheres.The weight of the pineal gland in adults is 150-200 mg. The surface is slightly bumpy, like a spruce cone, which is why it got its name. Produces hormone-like substance melatonin. Gradually undergoes involution. After the age of 8, there are signs of calcification, expressed in the deposition of “brain sand” (dark speck on the R-gram of the brain).

By its function, it inhibits the formation of somatotropic and gonadotropic hormones of the pituitary gland. Therefore, when the pineal gland is damaged or removed, premature sexual and physical development (macrogenitosomia praecox) occurs.

3. Thyroid gland

Consists of two lobes located on both sides of the trachea and thyroid cartilage, connected by an isthmus in the region of the 2nd to 4th rings of the trachea. The weight of the gland is 20–30 g. The thyroid gland takes the first place in the body in terms of blood supply.

Outside, the thyroid gland is covered with a fibrous capsule, from which thin layers extend into the parenchyma, dividing it into lobules. The lobules consist of follicles (thyrocytes), the cavity of which is filled with a viscous mass – a colloid.The colloid is mainly the iodine-containing protein thyroglobulin, which is a high molecular weight glycoprotein.

In the follicles, the biosynthesis of iodinated thyroid hormones occurs – triiodothyronine and tetraiodothyronine (thyroxine), which affect various types of metabolism, in particular, the basal metabolism. Their effect on the central nervous system, blood pressure, trophic processes, growth and development has been proven. Therefore, their lack leads to severe mental disorders, growth retardation.

In the interfollicular tissue, the hormone calcitonin is produced; its biological effect is manifested by a decrease in the level of calcium and phosphorus in the blood and is carried out through its effect on bone tissue and kidneys. The activity of the thyroid gland is regulated by the adenohypophysis, in which thyroid-stimulating hormone is produced.

4. Parathyroid glands

A person has two pairs of parathyroid glands (epithelial bodies). They are usually (in the form of millet grains) located at the corners of the posterior wall of the thyroid gland, but sometimes atypical.On average, the weight of these epithelial bodies is 0.15–0.25 g each.

The parathyroid glands produce parathyroid hormone (parathyroid hormone, parathyrin), which takes an active part in the regulation of mineral metabolism, primarily calcium and phosphorus. Normally, it maintains a constant blood calcium level.

5. Thymus gland (thymus)

For many years it was called “goiter”. But the name “goiter” is unfortunate, since the term “goiter” is associated with the word “goiter”, but goiter is the main symptom of thyroid diseases.The term “thymus” is more acceptable because it indicates the external shape of the organ.

The thymus gland is located behind the handle and partly the body of the sternum, in the upper part of the anterior mediastinum. The weight of the gland reaches its maximum by the age of 11–15 and is 25–35 g, and with the onset of puberty, it begins to undergo reverse development (involution).

A complex complex of hormonal agents is formed in the thymus gland. Among them, thymosin, thymopoietin, T-activin and others are distinguished.Thymic hormones stimulate the differentiation of T-lymphocytes, as well as promote their maturation. Therefore, it is no coincidence that the thymus is called the “center of immunity.”

The endocrine function of the thymus gland is not well understood. However, it is believed that there is a relationship between the thyroid gland, the pituitary gland, the adrenal glands, the sex glands, and the thymus.

The main syndromes caused by the pathology of the thymus gland are thymic-lymphatic status (status thymico-limphaticus) and myasthenia gravis (miastenia gravis).

6. Islet apparatus of the pancreas

The pancreas is located retroperitoneally, behind the stomach, at the level of I – II lumbar vertebrae. It consists of a head adjacent to the duodenum, a body and a tail that extends to the spleen. Its weight in an adult varies between 70-100 g. The length of the organ is up to 100 mm. Most of the pancreatic parenchyma is the exocrine apparatus (exocrine part), which secretes digestive enzymes: trypsin, lipase and amylase; through the small excretory ducts and the common Wirsung duct, which runs along the entire gland, they enter the duodenum and play an active role in the digestive process.

The endocrine part of the pancreas is represented by small islets of Langerhans (named after the author who first described them). They are diffusely distributed in the exocrine parenchyma of the gland (mainly the body and tail), accounting for 1–1.5% of the organ weight, and have a diameter of 50 to 400 µm. In the human pancreas, there are from 750 thousand to 2 million islets. The formation of islets of Langerhans occurs continuously throughout life from the epithelium of small excretory ducts. Islets are represented by a number of cell types.The main ones are: beta cells – 75–80%, which serve as a place for the synthesis and deposition of the hormone insulin; cells – 20-25%, produce glucagon; beta cells are the site of somatostatin formation. Alpha, delta, epsilon cells are also described. However, their function is not well understood.

Our compatriot L.V. Sobolev (1901).Only 20 years later, Canadian scientists Banting and Best obtained insulin from a dog’s pancreas for the first time. Insulin, as mentioned above, is produced by the beta cells of the islets, which is why its name arose ( insula in Latin means “islet”). Already in 1923, the first commercial insulin preparations were made, used to treat patients with diabetes mellitus.

Thus, a new era has emerged in the treatment of this common and severe disease.The chemical structure of insulin was deciphered in 1953 by Sanger and coworkers. The insulin molecule consists of two chains of amino acids – a short chain A (21 amino acids) and a long chain B (30 amino acids), connected by disulfide “bridges”. The closest in structure to human insulin is porcine insulin (the difference is only one amino acid: threonine is replaced by alanine).

It has been established that not all tissues are equally sensitive to insulin. Almost all nervous tissue can do without insulin.Insulin-sensitive include the liver, skeletal muscles, myocardium, adipose tissue, pituitary gland, leukocytes, lens and others.

It is known that the biological effect of insulin depends not only on the rate of its secretion, transport from the place of secretion to effector organs and tissues, but also on the ability of this hormone to bind to cells and the number of receptors. So, in diabetic ketoacidosis, the binding of insulin decreases by more than 50% due to a decrease in the affinity of insulin receptors for it.A decrease in the number of receptors is often the basis of the pathogenesis of type 2 diabetes mellitus.

Glucagon, produced by the alpha cells of the islet tissue, consisting of 29 amino acids, enhances glycogenolysis (breakdown of glycogen in the liver) and thereby causes transient hyperglycemia, is an insulin antagonist.

Lipocaine is also isolated from the pancreas, which stimulates the lipotropic effect of certain nutrients and inhibits the transition of liver carbohydrates to fats.

7. Adrenal glands

The adrenal glands are a paired vital organ of internal secretion. They are located above the upper poles of the kidneys at the level of the XI thoracic and I lumbar vertebrae. The mass of both adrenal glands ranges from 6 to 12 g. In shape they resemble a pyramid (“Napoleon’s hat”).

The adrenal gland consists of two layers of different origins – the outer cortex (interrenal tissue) and the inner medulla (adrenal tissue).

In turn, the adrenal cortex includes three zones: the outer glomerular zone (zona glomerulosa), the bundle zone (zona fasciculata) and the reticular zone (zona reticularis).

The medulla has a loose structure and is about 1/10 of the cortex in size. Over 40 compounds are produced by the cortical substance.

Since their chemical structure is based on a steroid ring of 17 carbon atoms, they are called 17-corticosteroids.

Of the 8 biologically active corticosteroids, only three are true hormones: hydrocortisone (or cortisol), corticosterone, and aldosterone. It is these three steroid compounds that can restore all the main disorders in the body that occur after the removal of the adrenal cortex, and save lives.

According to their physiological action, corticosteroids are divided into three groups: 1) glucocorticoids; 2) mineralocorticoids; 3) sex hormones (male – androgens, female – estrogens).

Glucocorticoids (hydrocortisone, corticosterone) have an effect on carbohydrate, protein and fat metabolism. With their participation, there is a deposition of glycogen in the liver, an increase in the formation of glycogen from protein, an increase in blood sugar and restoration of muscle tissue performance.

Mineralocorticoids (aldosterone, etc.) play an essential role in the regulation of water-salt metabolism. Aldosterone promotes the reabsorption of sodium ions, reduces its excretion in the urine, increases the excretion of potassium ions; as a result, it increases the hydrophilicity of tissues, plasma volume, and significantly increases blood pressure.

Sex hormones (androgens and estrogens) are involved in protein synthesis (anabolic action), the development of secondary sexual characteristics, and in the regulation of libido.

The content of hormones in the adrenal cortex during the day fluctuates: their maximum is contained in the morning, the minimum is in the evening.

The adrenal medulla produces the hormones catecholamines (adrenaline and norepinephrine), but the main site of norepinephrine synthesis is the sympathetic paraganglia. Adrenaline has a sympathicotropic effect: it enhances heart contractions, accelerates the pulse rate, increases blood pressure, relaxes the smooth muscles of the bronchi, intestines and constricts the vessels of the skin. Under the influence of adrenaline, the breakdown of glycogen in the liver increases, its conversion into glucose and the transition of sugar into the blood.In contrast, norepinephrine has almost no effect on carbohydrate metabolism and smooth muscle. Its main action is the narrowing of the arterioles of muscle tissue, as a result of which blood pressure rises.

The function of the adrenal cortex is under the constant regulatory influence of the central nervous system, the interstitial brain and the anterior pituitary gland.

The adrenal cortex has the property of responding to various influences (muscle tension, nervous shock, cooling, intoxication, trauma, burns, infection, etc.)) increased production of corticosteroid hormones. The condition that occurs in the body when exposed to strong stimuli is called “stress” (Selye). Strengthening the function of the adrenal cortex under conditions of exposure to strong stimuli on the body and the relief of emerging symptoms are considered as manifestations of a general nonspecific adaptation reaction.

8. Sex glands

The development of the gonads in embryogenesis is due to a set of sex chromosomes. Karyotype 46 XX determines the development of the ovaries, and 46 XY – the testicles

A.Male sex glands (testicles)

The testicles are a paired glandular organ located in the scrotum. Testicle length 3–5 cm, width 2–3 cm. Weight is 15–30 g. Testicles are covered with three membranes: serous, located outside, albuminous and vascular, directly adjacent to the parenchyma of the testes. From the tunica albuginea, the connective tissue septa fan out, dividing the testicular parenchyma into many lobules. Each lobule has convoluted and straight seminiferous tubules.The latter pass into the vas deferens, which combine into a tortuous duct that opens into the urethra.

The convoluted seminiferous tubules consist of spermatogenic epithelium and supporting cells (sustenocytes – Sertoli cells), rich in RNA and enzymes. They provide nourishment to the spermatogenic cells. Spermatogenic cells undergo successive changes and turn into spermatozoa.

The interstitial tissue between the tubules contains testicular interstitial granulocytes (Leydig cells).In granulocytes, androgens are formed – testosterone, androstenediol, dehydroepiandrosterone.

The male sex hormone is testosterone, the rest of the androgens are products of its metabolism. Under the influence of testosterone, the formation and growth of the external genital organs, the development of secondary sexual characteristics, the prostate gland, seminal vesicles, the formation of the skeleton and the muscular system, an increase in protein anabolism, the closure of growth zones in the bones, etc. Testosterone determines libido.

Testicular function is under the control of the hypothalamic-pituitary system. Sperm maturation occurs under the influence of follicle-stimulating hormone (FSH), and androgen secretion – under the influence of a hormone that stimulates interstitial cells. The latter in women is called luteinizing hormone (LH).

B. Female reproductive glands (ovaries)

The ovaries are a paired organ located in the pelvic cavity on the back leaf of its own ligament.The length of the ovary is 3-4 cm, the width is 2-2.5 cm, the weight is 6-7 g. The surface of the ovary is represented by a layer of cells of the embryonic epithelium. Under it is a dense connective tissue capsule (tunica albuginea). The ovary consists of the outer cortical and inner medulla. The latter has a loose base and a rich network of blood vessels. The ovarian hilum contains nests of cells that resemble testicular granulocytes (Leydig cells). These cells can release androgens.

The cortical substance contains sex cells – eggs, surrounded by rows of cells of granulosis and internal theca (follicles), which are at different stages of development.From the primordial epithelium in the ovary, primordial follicles develop, by the time of puberty their number is about 40,000.With the onset of puberty, only a small part of the primordial follicles (about 1/100) develops to a mature follicle – the vesicular ovarian follicle (graaf vesicle). The rest of the primordial follicles undergo reverse development. The maturation of the follicle lasts 12-14 days.

The follicle containing the enlarged oocyte, having moved to the surface of the ovary, bursts (ovulation).The latter occurs between the 14th and 16th days of the menstrual cycle. The ovocyte is secreted into the abdominal cavity, and then enters the fallopian tubes, where it turns into a mature egg and undergoes fertilization. In place of the vesicular ovarian follicle, a corpus luteum is formed from cells of granulosis and internal theca. The ovary produces two female sex hormones – progesterone and estradiol.

The corpus luteum produces progesterone. It creates conditions in the uterus for the perception of a fertilized egg and bearing a fetus, inhibits the contractile muscular excitability of the uterus, and stimulates the growth of alveoli in the mammary glands.

In the absence of fertilization of the egg, the corpus luteum functions for 10-12 days, and then undergoes a reverse development and menstruation begins. It usually lasts 3-5 days. The duration of the menstrual cycle is individual and is 21-24-28-30 days. At the end of pregnancy, the corpus luteum undergoes involution.

Estradiol is mainly produced in the cells of granulosa and internal theca. It is the most active estrogen. Its metabolic products estrone and estriol also have hormonal properties, but to a much lesser extent.Estrogens contribute to an increase in the size of the uterus, vagina, ensure the development of female secondary sexual characteristics (development of the mammary glands, the formation of a feminine figure, libido, etc.), have a protein-anabolic effect.

Ovarian function is also influenced by the hypothalamic-pituitary system.

As a result of the combined action of FSH and LH of the pituitary gland, follicles grow and develop, as well as the secretion and formation of estrogens by them.

Most endocrine diseases are caused by a pathological increase or decrease in the function of the corresponding glands.

Dysfunctions of the endocrine glands of the type of hyper- or hypofunction, leading to the development of endocrine pathology, are possible both as a result of damage to the glands themselves, and as a result of violations at various levels of their regulation.

The main function of hormones is to maintain the physiological balance of the internal environment – homeostasis.

Thus, we tried to remind colleagues about the importance of endocrinology as one of the important branches of medical science, the structure of the endocrine glands and, most importantly, about their functional purpose, the mechanism of formation and action of hormones.

Knowledge of the main problems of endocrinology is necessary for doctors of all specialties, as well as general practitioners, family doctors.

Self-regulation under stress

HomeAbout the projectNewsSelf-regulation under stress

08/24/2020

Our life passes in conditions of uncertainty, risk, pressure of time and circumstances. Therefore, managing your stress, emotional state and vitality is a key skill that determines the professional effectiveness of an individual.At a webinar with a teacher of Tibetan yoga and qigong, Alexei Shchavelev, we studied self-regulation technologies and practices to maintain biological youth. The main results of the webinar are collected for you in this material.

WHY STRESS IS OUR FRIEND AND HOW IT CAN KILL US

Fall in love with stress. It is an adaptive response of the body that gives us access to energy resources. Thanks to stress, we are saved from danger, in a critical situation it saves life.And during times of moderate stress, we achieve maximum efficiency.

At the same time, we spend a huge amount of biological resources and nervous energy on stress. If we cannot control him, he turns into our killer. Yes, you can die from psychosomatic diseases that cause chronic stress! But we will learn to turn stress in our favor, restore energy resources and direct all the energy of mobilization towards achieving the goal.

If you are a leader, keeping stress in check is especially important.There is such an anecdote. Colonels never run: in peacetime this is funny, and in wartime it leads to panic among subordinates. So it is with any leader: he must act productively and expediently, use stress to solve a problem, and not for empty emotions.

Never believe the first stressful reaction! The choice of the brain – what is dangerous and what is not dangerous – is unreliable. You need to verify the information, understand your goals in the situation, and identify resources. Of course, in a difficult situation, you want to give up and just panic.But stress will only help if you direct it somewhere by a volitional effort. If you don’t, the body’s reactions will be primitive: hit, run or freeze. But most of today’s stressful situations require something completely different! For them, presence of mind is important – the ability not to turn off those areas of the brain that are responsible for rational control of the situation and volitional actions.

BIOLOGY OF STRESS

Stress is hazardous to health because the entire body is involved.Regardless of whether you are fighting for life on a ship in a storm or worried about a quarterly report in a warm office.

Stress is an automatics of the brain. The neural network of the hippocampus – one of the parts of the limbic system of the brain – stores information about all the dangers in our life. Moreover, the one that we personally did not experience, but about which we simply heard, read and which we saw. When a stimulus from the external environment arises, the brain runs it through this database. If the brain recognizes the situation as dangerous, it transmits information to the amygdala.It triggers a stress response, gives the body a signal to mobilize. After 250 milliseconds, we will know about it too.

Imagine: you are sitting at work, an important letter arrives. You opened it and suddenly became alert. Your eyes noticed something, and you felt uneasy, even though you haven’t even read the letter yet. It was your brain that noticed a familiar detail and recognized it as a hazard. When you read the letter, there may be nothing wrong with it, it was just a negative brain association.

Our brain controls the internal organs through the circuits of the autonomic nervous system. All organs are surrounded by two types of nerves: sympathetic and parasympathetic.

The sympathetic nervous system is your body’s gas pedal. It is activated during stress, helps to quickly do something, increases the speed of metabolic processes.

The parasympathetic nervous system is the brake pedal in the body. It maintains homeostasis.

The harder you throttle, the better your brake should be! If the imbalance between the gas and the brake is prolonged, a state of nervous exhaustion will occur.

Here the brain determined that the stimulus is stressful, and started the work of the amygdala. Cerebral norepinephrine is immediately released – a neurochemical impulse is transmitted and a landslide reaction is triggered throughout the body. The sympathetic nervous system starts to work.

• instantly dilates the pupil,
• decreased salivation,
• bronchi dilate,
• breathing becomes intense,
• the heart rate increases,
• stimulates the release of glucose by the liver,
• the release of adrenaline is stimulated,
• digestion slows down – the stomach temporarily stops digesting food,
• relaxes the bladder,
• the rectum contracts.

The body no longer spends energy on homeostasis processes. He is ready to fend off danger or run away from it.

If stress is one-time, these processes are normal. And if chronic?

The stomach suffers. Our stomach contains hydrochloric acid. To prevent it from digesting itself, special cells in the mucous membrane secrete a protective gel. In chronic stress, the microcapillaries that penetrate the mucous membrane spasm, the cells work poorly, and the gel turns out to be diluted.Non-infectious gastritis develops and then an ulcer. In chronic stress, food is no longer processed with hydrochloric acid, is not absorbed through the intestinal wall and turns into fecal stones. Intestinal diverticulosis may begin.

Hormones

The impulse along the nerve fibers reaches the organs of the endocrine system – the adrenal glands. They produce a large number of hormones that are involved in stress mobilization.

Unlike neurotransmitters, which transmit an electrochemical signal through a nerve fiber from neuron to neuron, hormones are released directly into the blood as a liquid.

Three of them are worth remembering:

Adrenaline is responsible for the “run” response.

The heart begins to jump out of the chest. Vessels spasm sharply and unevenly – pressure increases in them. The microcapillaries that penetrate the internal organs are in a spasm, they do not have enough blood, because it is directed to where the other type of receptors is – to the large muscles. Feel hot inside during stress? This blood is evacuated into large muscles to allow you to react quickly and escape.

Hypoxia (oxygen starvation) of the organs begins. When you draw air into your lungs, this is not breathing, it is gas exchange. Breathing is when the blood delivers red blood cells with oxygen molecules to the mitochondria of the cells and there the Krebs cycle and the production of adenosine triphosphate take place.

Internal organs begin to signal to the brain to increase the pressure. After that, the vessels contract even more, become solid, and increase the density of the shell.The result is hypertension. This is a common disease of modern managers.

Have you heard about adrenaline addiction? It is a myth. If a person is injected with adrenaline, he will feel cold in his hands and feet, his heart will pound. I definitely don’t want repetition. Why does addiction arise in extreme sports? During times of extreme stress, the brain begins to prepare us for trauma. To prevent us from dying from painful shock, analgesics – endogenous opioids – are released.For example, endorphins. When you jump with a parachute and feel euphoric, analgesics work. The addiction comes not at all from adrenaline, but from analgesics.

Norepinephrine is responsible for the “attack” reaction, mobilizes the muscles.

Cortisol is responsible for the freeze response.

This hormone dramatically increases blood glucose – it converts glycogen into sugar. When glycogen runs out, it is taken up by fat and muscle tissue.

Cortisol keeps our sugar high, which sooner or later leads to diabetes. Insulin is also constantly released. Cells sooner or later remove receptors that respond to insulin; now glucose does not enter the cells, there is a lot of it in the blood, and glycated hemoglobin appears, which destroys blood vessels.

With prolonged stress, cortisol destroys the organs responsible for the immune system, such as the thymus gland, which produces thymus-dependent lymphocytes that mark cells infected with the virus.During prolonged stress, a person loses immunity. On the other hand, with a one-time stress, immunity rises.

After stress, the body turns on parasympathetic. You are safe, the brain is inhibited, secreting a special neurotransmitter – acetylcholine.

• pupils constrict,
• stimulates salivation and digestion,
• breathing returns to normal,
• muscles relax,
• pressure drops,
• stabilizes the level of stress hormones.

The body gradually goes into a dream-like state and then into deep sleep. It seems to us that during sleep we are simply turned off. No, we have the brake pedal pressed. Special neurohormones provide recuperation. One of them you probably know is melatonin.

IMPROVEMENT OF BALANCE

All our conditions depend on the release of certain substances by the brain and the glands of the endocrine system. For example, our engagement and motivation are linked to the release of dopamine.When it is not enough, apathy sets in.

Remember: if you do not switch, do not press the “brake”, then bring yourself to nervous exhaustion: the neurons of the brain cease to secrete the right substances in the right amount, and you do not get pleasure from life and lose motivation to work.

Burnout is included in the WHO list of diseases. But this is more likely not a disease, but a syndrome! Psycho-emotional trauma and exhaustion from chronic stress can be behind it.Does a person think slowly, make bad decisions and shout at people? No, it’s not burnout, it’s neurasthenia. Those who dislike the term are talking about burnout. Another term has been coined for larger executives: strategic fatigue. And it doesn’t exist either. Are you making the wrong decisions, falling for people? This is not fatigue, this is neurasthenia.

WHAT TO DO AND HOW TO FIND THE BALANCE

The best way to recover is breathing exercises based on hypercapnia.For example, extended breathing, when the oxygen level does not fall, but the CO2 level in the blood rises. The brain perceives this as a threat and instructs the smooth muscles to expand and save the body. After five minutes of stretched breathing, your arms and legs are warming up, your face turns pink.

A supplement – the amino acid L-arginine – is suitable for relaxing smooth muscles. When concentrated in the liver, it is rapidly metabolized to nitric oxide, which expands smooth muscle.To relieve a chronic spasm, it is enough to take three grams of L-arginine at night on an empty stomach. You can start with one gram and work up to three. It is especially important to take L-arginine during periods of stress.

If you are stressed, do breathing exercises and relieve spasms with L-arginine. After nervous tension, physical activity is required.

Can you relax with alcohol?

If you don’t use up your stress hormones as intended, they kill you.Worst case: get nervous at work and drink alcohol at home. The physiological norm that the body can process is 30-40 grams in terms of pure alcohol. These are two glasses of wine. The main problem is to stop on time. A few glasses can bring temporary relaxation, and we will want more.

After alcohol, the capillaries really expand, but the enzyme in the liver may not be enough to process the alcohol. It gets into the blood. A high concentration of alcohol in the blood defattes red blood cells.They lose their shells and begin to stick together. In the blood, clots of red blood cells are already moving, which the blood cannot tolerate. The next morning we feel bad, because the whole night the body was in a state of oxygen starvation.

Yes, the vessels expanded briefly, but the body still suffered. So no more than two glasses of wine at dinner! Any external support for the body comes at a cost. Better to rely on self-regulation methods.

SYMPTOMS OF CHRONIC VEGETATIVE VOLTAGE

How to understand the problem? One-time stress is easy to spot.But we get used to the chronic, the psyche does not notice it anymore, the person forgets what it means to live without stress.

Rate how each of these symptoms have been typical for you over the past two weeks. Give 3 points if the symptom was clearly manifested; 2 points – was, but in an average degree; 1 point – manifested weakly; 0 – there was no symptom.

• Spasm of blood vessels and capillaries: cold hands and feet, pale skin, hypertension. Pay particular attention to the lower pressure: if it is high, the vessels are in spasm.
• “Muscle Armor”. The striated muscles are tense: biceps, triceps. When you press on the muscles, you feel pain, you cannot relax before going to bed.
• Chronic fatigue, low energy level. Normal fatigue builds up in the evening, but when you have eaten, slept, rested, it goes away. If you are tired already in the morning – this is a bell.
• Dizziness, poor concentration and memory.
• Poor digestion, gastritis, ulcer.When you have eaten the right food, not fast food, and the stomach is still heaviness is a sign of stress.
• Decreased immunity. Measure it in three months. Diseases last a long time, chronic diseases develop, herpes may appear.
• Decreased sleep quality. More than 20 minutes you cannot fall asleep, sleep is shallow, there is a feeling of a working head, it is hard to wake up in the morning.
• Anhedonia – inability to enjoy simple things: entertainment, food, sleep.
• Dysphoria – long-term unreasonable mood disorder, anxiety, irritation to other people, aggression.
• Addictive, or dependent, behavior – escape from reality by artificially changing the mental state. For example, tobacco smoking, alcoholism, overeating, Internet addiction, etc.

(How to assess that you have an addiction. What will happen if you are deprived of this object: alcohol, computer games, tobacco, coffee? Will your mood and behavior change, can you spend a long time without it?)

If you scored up to 10 points, you have a balance between gas and brake.

If you have between 10 and 20 points, you are wasting more energy than you are able to recover.

If you scored more than 20 points, then you have chronic stress, parasympathetic does not work.

• Take a stress hormone test. For example, elevated cortisol indicates either stress or Cushing’s syndrome.

• Pay attention to changes in heart rate variability. In a healthy person, the time intervals between heart beats are always different by milliseconds.If your heart beats like a metronome, your body is exhausted or sick.

BREATHING EXERCISES

Breathe through your nose. Close your eyes. Place one hand on your stomach and the other on your chest. Begin to breathe with your belly, smoothly fill the bottom of your lungs with air, then open your chest and fill all the lungs with air under the collarbones. This will lower your diaphragm and fill your blood with carbon dioxide. Exhale smoothly for a long time. Inhale again immediately.

Concentrate on your breathing. Don’t breathe automatically. Let the mind recognize moment by moment how the breath is taking place. Let go of external stimuli or internal thoughts, return your attention to the breath.

As soon as the diaphragm began to move, the vagus nerve was stimulated, which switches you to parasympathetic control. An extended inhalation and exhalation fill the blood with oxygen and, at the same time, with carbon dioxide.

Draw air into your lungs and hold your breath.Drop your head limply on your chest, roll back, make a circle with your head. Tilt your head back, focus on the deflection in the thoracic vertebrae, raise your head and exhale slowly.

This closes the blood flow to the brain, and it begins to release endogenous opioids. It is enough to do this 3-4 times, and the opioids will be restored.

MEDITATIVE PRACTICE FOR DAILY SELF-REGULATION

Sit down, straighten your back, feel the stability of your body.Place your hands on your knees, palms up. Pull the top of the head up: there should be a feeling that the distance between the vertebrae is increasing. The body is relaxed, the back is straight.

Close your eyes. Bring your attention to your feet. What is the temperature of your feet? How do they feel the surface? Don’t think about feet, just watch how you feel.

Move your attention smoothly to your hands. How do your fingertips, the middle of your palms feel?

Grab your entire body with attention.Feel the legs, arms, torso, and head. Feel the skeleton and internal organs. How do sensations change under your supervision? The body starts to get heavy, the muscles relax. Watch your body continuously. If you notice a thought, immediately return from it to observation.

Direct your attention to your mind. Notice the appearance of a thought, image, picture and release. If one thought is gone and the other is not, stay paused. Do not crush your thoughts, you will not be able to get rid of them. Just return to observation and the mind will calm down on its own.To calm the water in a glass, you do not need to swing it in your hand. Just don’t touch the glass and the liquid will calm down on its own.

How to understand that you are meditating:

• The ray of attention is directed to one object.
• You are aware of the object moment by moment continuously.
• You always understand in what tone your attention is. You can bring it back and strengthen it.