Glands of the endocrine system. What is the human endocrine system and its main functions

Endocrine system human is a collection of special organs (glands) and tissues located in different parts organism.

glands produce biologically active substances - hormones(from the Greek hormáo - set in motion, encourage), which act as chemical agents.

Hormones are released into the intercellular space, where it is picked up by the blood and transferred to other parts of the body.

Hormones affect the activity of organs, changing physiological and biochemical reactions by activating or inhibiting enzymatic processes (processes of accelerating biochemical reactions and regulating metabolism).

That is, hormones exert on target organs specific action, which, as a rule, are not able to reproduce other substances.

Hormones are involved in all processes of growth, development, reproduction and metabolism

Chemically, hormones are a heterogeneous group; the variety of substances presented by them includes

Glands that produce hormones are called glands internal secretion , endocrine glands.

They secrete the products of their vital activity - hormones - directly into the blood or lymph (pituitary gland, adrenal glands, etc.).

There are also glands of another kind - exocrine glands(exocrine).

They do not release their products into the bloodstream, but release secretions onto the surface of the body, mucous membranes, or into the external environment.

it sweat, salivary, lacrimal, dairy glands and others.

The activity of the glands is regulated by the nervous system, as well as humoral factors(factors from liquid medium organism).

The biological role of the endocrine system is closely related to the role nervous system.

These two systems mutually coordinate the function of others (often separated by a considerable distance of organs and organ systems).

The main endocrine glands are the hypothalamus, pituitary gland, thyroid gland, parathyroid glands, pancreas, adrenal glands and gonads.

The central link of the endocrine system is the hypothalamus and pituitary gland

Hypothalamus- This is an organ of the brain, which, like a control room, gives orders for the production and distribution of hormones in the right amount and at the right time.

Pituitary gland located at the base of the skull that secretes a large number of trophic hormones - those that stimulate the secretion of other endocrine glands.

The pituitary and hypothalamus are securely protected by the skeleton of the skull and made by nature in a unique for each organism, a single copy.

Human endocrine system: endocrine glands

Peripheral link of the endocrine system - thyroid gland, pancreas, adrenal glands, gonads

Thyroid- secretes three hormones; located under the skin in the anterior surface of the neck, and protected from the upper respiratory tract halves of the thyroid cartilage.

Adjacent to it are four small parathyroid glands involved in calcium metabolism.

Pancreas This organ is both exocrine and endocrine.

As an endocrine hormone, it produces two hormones - insulin and glucagon, which regulate carbohydrate metabolism.

The pancreas produces and supplies digestive tract enzymes to break down food proteins, fats and carbohydrates.

Adrenal glands border the kidneys, uniting the activity of two types of glands.

adrenal glands- are two small glands, located one above each kidney and consisting of two independent parts - the cortex and the medulla.

gonads(ovaries in women and testicles in men) - produce germ cells and other major hormones involved in reproductive function.

As we already know all endocrine glands and individual specialized cells synthesize and secrete hormones into the blood.

The exceptional power of the regulating effect of hormones on all body functions

Them signal molecule causes a variety of changes in metabolism:

They determine the rhythm of the processes of synthesis and decay, implement a whole system of measures to maintain water and electrolyte balance- in a word, create an individual optimal internal microclimate, characterized by stability and constancy, due to its exceptional flexibility, ability to respond quickly and specificity of regulatory mechanisms and systems controlled by them.

The loss of each of the components of hormonal regulation from the general system disrupts the single chain of regulation of body functions and leads to the development of various pathological conditions.

The demand for hormones is determined by the local conditions that arise in the tissues or organ most dependent on a particular chemical legislator.

If we imagine that we are in a mode of increased emotional stress, then metabolic processes are intensified.

It is necessary to provide the body with additional means to overcome the problems that have arisen.

Glucose and fatty acids, easily disintegrating, can provide the brain, heart and tissues of other organs with energy.

They do not need to be urgently administered with food, since there are reserves of glucose polymer in the liver and muscles - glycogen, animal starch, and adipose tissue reliably provides us with reserve fat.

This metabolic reserve is renewed, maintained in good condition by enzymes, using them when necessary and promptly replenished at the first opportunity, when the slightest excess appears.

Enzymes capable of breaking down the products of our reserves consume them only on command brought to the tissues by hormones.

Dietary supplements regulating the work of the endocrine system

The body produces many hormones

They have a different structure, they have a different mechanism of action, they alter the activity of existing enzymes and regulate the process of their biosynthesis anew, causing the growth, development of the body, the optimal level of metabolism.

A variety of intracellular services are concentrated in the cell - processing systems nutrients, transforming them into elementary simple chemical compounds, which can be used at the discretion of the site (for example, to maintain a certain temperature regime).

Our body lives at the optimal temperature regime for it - 36-37 ° C.

Normally, there are no sudden temperature changes in the tissues.

Sudden change in temperature for an organism not prepared for this - devastating destruction factor, contributing to a gross violation of the integrity of the cell, its intracellular formations.

The cell has power stations whose activities are mainly focused on energy storage.

They are represented by complex membrane formations - mitochondria.

Specificity of activity mitochondria consists in the oxidation, splitting of organic compounds, nutrients formed from proteins (carbohydrates and fats of food), but as a result of previous metabolic transformations that have already lost the signs of biopolymer molecules.

Decay in mitochondria is associated with the most important process for life.

There is a further disaggregation of molecules and the formation of an absolutely identical product, regardless of the primary source.

This is our fuel, which the body uses very carefully, in stages.

This allows not only to receive energy in the form of heat, which ensures the comfort of our existence, but also mainly to accumulate it in the form of the universal energy currency of living organisms - ATP ( adenosine triphosphate).

The high resolution of electron microscope devices made it possible to recognize the structure of mitochondria.

Fundamental research by Soviet and foreign scientists contributed to the knowledge of the mechanism of a unique process - energy accumulation, which is a manifestation of the function of the inner membrane of mitochondria.

At present, an independent branch of knowledge about the energy supply of living beings has been formed - bioenergetics, which studies the fate of energy in the cell, the ways and mechanisms of its accumulation and use.

in mitochondria biochemical processes transformations of molecular material have a certain topography (location in the body).

Enzymatic oxidation systems fatty acids, amino acids, as well as a complex of biocatalysts that form a single cycle for the decomposition of carboxylic acids as a result of previous reactions of the decomposition of carbohydrates, fats, proteins that have lost their resemblance to them, impersonal, unified up to a dozen of the same type of products, located in the mitochondrial matrix- make up the so-called cycle citric acid, or the Krebs cycle.

The activity of these enzymes allows you to accumulate in the matrix a powerful force of energy resources.

Thereby mitochondria figuratively called cell powerhouses.

They can be used for processes of reductive synthesis, and also form a combustible material from which a set of enzymes, mounted asymmetrically across the inner membrane of mitochondria, extracts energy for the life of the cell.

Oxygen serves as an oxidizing agent in exchange reactions.

In nature, the interaction of hydrogen and oxygen is accompanied by an avalanche-like release of energy in the form of heat.

When considering the functions of any cell organelles ("organs" of protozoa), it becomes obvious how their activity and the mode of operation of the cell depend on the state of the membranes, their permeability, the specifics of the set of enzymes that form them and serve building material these formations.

An analogy is valid between texts - a set of letters that form words that form phrases, and a way to encrypt information in our body.

This refers to the sequence of alternation of nucleotides (an integral part of nucleic acids and other biologically active compounds) in a DNA molecule - a genetic code in which, as in an ancient manuscript, the necessary information about the reproduction of proteins inherent in a given organism is concentrated.

An example of encoding information in the language of organic molecules is the presence of a receptor recognized by a hormone, recognizing it among the mass of various compounds that collide with the cell.

When a compound rushes into a cell, it cannot spontaneously penetrate into it.

The biological membrane serves as a barrier.

However, a specific carrier is prudently built into it, which delivers the candidate for intracellular localization to its destination.

Is it possible for an organism to have a different "interpretation" of its molecular designations - "texts"? It is quite obvious that this is the real way to the disorganization of all processes in cells, tissues, organs.

"Foreign Diplomatic Service" allows the cell to navigate the events of extracellular life at the organ level, to constantly be aware of current events throughout the body, following the instructions of the nervous system with the help of hormonal control, receiving fuel and energy and building material.

In addition, inside the cell, its own molecular life is constantly and harmoniously going on.

Cellular memory is stored in the cell nucleus - nucleic acids, in the structure of which the program for the formation (biosynthesis) of a diverse set of proteins is encoded.

They perform a building and structural function, are biocatalysts-enzymes, can carry out the transport of certain compounds, play the role of defenders from foreign agents (microbes and viruses).

The program is contained in the nuclear material, and the work of building these large biopolymers is carried out by a whole conveyor system.

In a genetically strictly defined sequence, amino acids, building blocks of a protein molecule, are selected and fastened into a single chain.

This chain can have thousands of amino acid residues.

But in the microcosm of the cell it would be impossible to place all the necessary material if it were not for its extremely compact packaging in space.

The endocrine system includes all the glands in the body and the hormones produced by those glands. The glands are controlled directly by stimulation of the nervous system, as well as by chemical receptors in the blood and hormones produced by other glands.
By regulating the functions of the organs in the body, these glands help maintain the homeostasis of the body. Cellular metabolism, reproduction, sexual development, sugar level and minerals, heart rate and digestion are some… [Read below]

• Head and neck
• upper body
• Lower body (M)
• Lower body (F)

[Beginning at the top] … of the many processes regulated by the action of hormones.

Hypothalamus

It is the part of the brain located above and in front of the brainstem, inferior to the thalamus. She performs many various functions in the nervous system, and is also responsible for the direct control of the endocrine system through the pituitary gland. The hypothalamus contains special cells called neurosecretory cells—neurons that secrete endocrine hormones: thyrotropin-releasing (TRH), growth hormone-releasing (GRH), growth inhibitory (GRH), gonadotropin-releasing hormone (GRH), corticotropin-releasing (CRH), oxytocin, antidiuretic (ADH).

All releasing and inhibitory hormones affect the function of the anterior pituitary gland. TRH stimulates the anterior pituitary gland to release thyroid-stimulating hormone. GRH and GRH regulate the release of growth hormone, GH stimulates the release of growth hormone, GRH inhibits its release. HRH stimulates the release of follicle-stimulating hormone and luteinizing hormone, while CRH stimulates the release of adrenocorticotropic hormone. The last two endocrine hormones - oxytocin, as well as antidiuretic - are produced by the hypothalamus, then transferred to the posterior pituitary gland, where they are, and then released.

Pituitary

The pituitary gland is a small, pea-sized piece of tissue connected to bottom the hypothalamus of the brain. Many blood vessels surround the pituitary gland, distributing hormones throughout the body. Located in a small depression of the sphenoid bone, the Turkish saddle, the pituitary gland actually consists of 2 completely different structures: the posterior and anterior pituitary glands.

Posterior pituitary.
The posterior pituitary is not actually a glandular tissue, but more of a nervous tissue. The posterior pituitary gland is a small extension of the hypothalamus through which the axons of some of the neurosecretory cells of the hypothalamus pass. These cells create 2 types of hypothalamic endocrine hormones that are stored and then released by the posterior pituitary: oxytocin, antidiuretic.
Oxytocin activates uterine contractions during childbirth and stimulates the release of milk during breastfeeding.
An antidiuretic (ADH) in the endocrine system prevents body water loss by increasing water reabsorption by the kidneys and decreasing blood flow to the sweat glands.

Adenohypophysis.
The anterior pituitary gland is the true glandular part of the pituitary gland. The function of the anterior pituitary controls the releasing and inhibitory functions of the hypothalamus. The anterior pituitary produces 6 important hormones endocrine system: thyroid-stimulating (TSH), responsible for stimulation thyroid gland; adrenocorticotropic - stimulates the outer part of the adrenal gland - the adrenal cortex to produce its hormones. Follicle-stimulating (FSH) - stimulates the bulb of the gonadal cell to produce gametes in females, sperm in males. Luteinizing (LH) - stimulates the gonads to produce sex hormones - estrogens in women and testosterone in men. Human growth hormone (GH) affects many target cells throughout the body, stimulating them to grow, repair, and reproduce. Prolactin (PRL) - has many effects on the body, the main one being that it stimulates the mammary glands to produce milk.

pineal gland

It is a small, knobby-shaped mass of endocrine glandular tissue found just behind the thalamus of the brain. It produces melatonin, which helps regulate the sleep-wake cycle. The activity of the pineal gland is inhibited by stimulation from retinal photoreceptors. This sensitivity to light causes melatonin to be produced only in low light or dark conditions. The increase in melatonin production makes people feel sleepy at night when the pineal gland is active.

Thyroid

The thyroid gland is a butterfly-shaped gland located at the base of the neck and wrapped around the sides of the windpipe. It produces 3 main hormones of the endocrine system: calcitonin, thyroxine and triiodothyronine.
Calcitonin is released into the blood when calcium levels rise above set value. It serves to reduce the concentration of calcium in the blood, promoting the absorption of calcium in the bones. T3, T4 work together to regulate the body's metabolic rate. Increasing the concentration of T3, T4 increases energy consumption, as well as cellular activity.

parathyroid glands

In the parathyroid glands 4 are small masses of glandular tissue found on the posterior side of the thyroid gland. The parathyroid glands produce an endocrine hormone, parathyroid hormone (PTH), which is involved in the homeostasis of calcium ions. PTH is released from the parathyroid glands when the level of calcium ions is lower given point. PTH stimulates osteoclasts to break down calcium containing matrix bone tissue to release free calcium ions into the blood. PTH also stimulates the kidneys to return filtered calcium ions from the blood back into the bloodstream so that they are retained.

adrenal glands

The adrenal glands are a pair of roughly triangular endocrine glands located just above the kidney. They consist of 2 individual layers, each with its own unique functions: the outer adrenal cortex, as well as the inner adrenal medulla.

Adrenal cortex:
produces many cortical endocrine hormones of 3 classes: glucocorticoids, mineralocorticoids, androgens.

Glucocorticoids have many different functions, including the breakdown of proteins and lipids to produce glucose. Glucocorticoids also function in the endocrine system to reduce inflammation and enhance the immune response.

Mineralocorticoids, as their name suggests, are a group of endocrine hormones that help regulate the concentration of mineral ions in the body.

Androgens, such as testosterone, are produced at low levels in the adrenal cortex to regulate the growth and activity of cells that are receptive to male hormones. In adult males, the amount of androgens produced by the testes is many times greater than that produced by the adrenal cortex, resulting in male secondary sexual characteristics such as facial hair, body hair, and others.

Adrenal medulla:
it produces epinephrine and norepinephrine when stimulated sympathetic department VNS. Both of these endocrine hormones help increase blood flow to the brain and muscles to improve the response to stress. They also work to increase heart rate, respiratory rate, blood pressure by reducing blood flow to organs that are not involved in emergency response.

Pancreas

This is a large gland located in the abdominal cavity of the lower back closer to the stomach. The pancreas is considered a heterocrine gland because it contains both endocrine and exocrine tissues. The endocrine cells of the pancreas make up only about 1% of the mass of the pancreas and are found in small groups throughout the pancreas called the islets of Langerhans. Within these islets, there are 2 types of cells - alpha and beta - cells. Alpha cells produce glucagon, which is responsible for increasing glucose levels. Glucagon stimulates muscle contractions liver cells to break down the polysaccharide glycogen and release glucose into the blood. Beta cells produce insulin, which is responsible for lowering blood glucose after meals. Insulin causes glucose to be absorbed from the blood into cells, where it is added to glycogen molecules for storage.

Gonads

Gonads - organs of the endocrine and reproductive system - ovaries in females, testes in males - are responsible for the production of sex hormones in the body. They determine the secondary sexual characteristics of adult females and adult males.

testicles
are a pair of ellipsoid organs found in the scrotum of males that produce the androgen testosterone in males after the onset of puberty. Testosterone affects many parts of the body, including muscles, bones, genitals, and hair follicles. It causes the growth and increase in the strength of bones, muscles, including accelerated growth long bones in adolescence. During puberty, testosterone controls the growth and development of male genitals and body hair, including pubic, chest, and facial hair. In men who have inherited baldness genes, testosterone causes onset androgenetic alopecia commonly known as male pattern baldness.

Ovaries.
The ovaries are a pair of tonsil-shaped endocrine and reproductive glands located in the pelvic cavity of the body, superior to the uterus in women. The ovaries produce the female sex hormones progesterone and estrogens. Progesterone is most active in women during ovulation and pregnancy, where it provides the right conditions in the human body to support the developing fetus. Estrogens are a group of related hormones that function as the primary female reproductive organs. The release of estrogen during puberty causes the development of female sexual characteristics (secondary) - this is the growth of pubic hair, the development of the uterus and mammary glands. Estrogen also causes increased bone growth during adolescence.

thymus

The thymus is a soft, triangular organ of the endocrine system located in the chest. The thymus synthesizes thymosins, which train and develop T-lymphocytes during fetal development. T-lymphocytes obtained in the thymus protect the body from pathogenic microbes. The thymus is gradually replaced by adipose tissue.

Other hormone-producing organs of the endocrine system
In addition to the endocrine glands, many other non-glandular organs and tissues in the body also produce endocrine hormones.

Heart:
muscle The heart is capable of producing the important endocrine hormone atrial natriuretic peptide (ANP) in response to high blood pressure levels. PNP works to lower blood pressure by causing vasodilation to provide more room for blood to pass through. ANP also reduces blood volume and pressure, causing water and salt to be excreted from the blood through the kidneys.

Kidneys:
produce the endocrine hormone erythropoietin (EPO) in response to low blood oxygen levels. EPO, once released by the kidneys, is sent to the red bone marrow, where it stimulates increased production of red blood cells. The number of red blood cells increases throughput blood oxygen, eventually stopping the production of EPO.

Digestive system

The hormones cholecystokinin (CCK), secretin and gastrin, are all produced by the organs of the gastrointestinal tract. intestinal tract. CCK, secretin and gastrin help regulate the secretion of pancreatic juice, bile, and gastric juice in response to the presence of food in the stomach. CCK also plays a key role in feeling full or "full" after a meal.

Adipose tissue:
produces the endocrine hormone leptin, which is involved in controlling appetite and energy expenditure in the body. Leptin is produced at levels relative to the amount of adipose tissue present in the body, which allows the brain to control the state of energy storage in the body. When the body contains sufficient levels of adipose tissue to store energy, the level of leptin in the blood tells the brain that the body is not starving and can function normally. If adipose tissue or leptin levels fall below a certain threshold, the body goes into starvation mode and attempts to conserve energy by increasing hunger and food intake and reducing energy intake. Adipose tissue also produces very low levels of estrogen in men and women. In obese people, a large amount of adipose tissue can lead to abnormal estrogen levels.

Placenta:
In pregnant women, the placenta produces several endocrine hormones that help keep the pregnancy going. Progesterone is produced to relax the uterus, protect the fetus from immune system mother, and also prevents premature birth of the fetus. Chorionic gonadotropin (HCG) helps progesterone, by signaling the ovaries, to maintain estrogen and progesterone production throughout pregnancy.

Local endocrine hormones:
prostaglandins and leukotrienes are produced by every tissue in the body (with the exception of blood tissue) in response to noxious stimuli. These two hormones of the endocrine system affect cells that are local to the source of damage, leaving the rest of the body free to function normally.

Prostaglandins cause swelling, inflammation, hypersensitivity to pain and fever of the local organ, to help block damaged areas of the body from infection or further damage. They act like the body's natural bandages, keep pathogens at bay, and swell around injured joints like a natural bandage to limit movement.

Leukotrienes help the body heal after the prostaglandins have taken over by reducing inflammation by helping white blood cells move into the area to clear it of pathogens and damaged tissue.

Endocrine system, interaction with the nervous. Functions

The endocrine system works together with the nervous system to form the body's control system. The nervous system provides very fast and highly targeted control systems for the regulation of specific glands and muscles throughout the body. The endocrine system, on the other hand, is much slower in action, but has very wide distribution, long lasting and powerful effects. Endocrine hormones are distributed by glands through the blood throughout the body, affecting any cell with a receptor for a particular species. Most affect cells in multiple organs or throughout the body, resulting in many varied and powerful responses.

Hormones of the endocrine system. Properties

Once the hormones have been produced by the glands, they are distributed throughout the body through the bloodstream. They travel through the body, through cells, or along the plasma membrane of cells until they encounter a receptor for that particular endocrine hormone. They can only affect target cells that have the appropriate receptors. This property is known as specificity. Specificity explains how each hormone can have specific effects in common parts of the body.

Many hormones produced by the endocrine system are classified as tropic. Tropics are able to cause the release of another hormone in another gland. These provide a control pathway for the production of hormones, as well as a way for the glands to control production in remote areas of the body. Many of those produced by the pituitary gland, such as TSH, ACTH, and FSH, are tropic.

Hormonal regulation in the endocrine system

The levels of endocrine hormones in the body can be regulated by several factors. The nervous system can control hormone levels through the action of the hypothalamus and its release and inhibitors. For example, TRH produced by the hypothalamus stimulates the anterior pituitary gland to produce TSH. Tropics provide an extra layer of control for hormone release. For example, TSH is tropic, stimulating the thyroid to produce T3 and T4. Nutrition can also control their levels in the body. For example, T3 and T4 require 3 or 4 iodine atoms, respectively, then they will be produced. People who do not have iodine in their diet will not be able to produce enough thyroid hormone to maintain a healthy metabolism in the endocrine system.
Finally, the number of receptors present in cells can be changed by the cells in response to hormones. Cells that are exposed high levels hormones for long periods of time can reduce the number of receptors they produce, resulting in decreased cell sensitivity.

Classes of endocrine hormones

They are divided into 2 categories based on their chemical composition and solubility: water-soluble and fat-soluble. Each of these classes has specific mechanisms and functions that dictate how they affect target cells.

water soluble hormones.
Water-soluble ones include peptide and amino acids such as insulin, epinephrine, growth hormone (somatotropin) and oxytocin. As their name suggests, they are water soluble. Water solubles cannot pass through the phospholipid bilayer of the plasma membrane and are therefore dependent on receptor molecules on the cell surface. When a water-soluble endocrine hormone binds to a receptor molecule on the surface of a cell, it causes a reaction within the cell. This reaction can change factors within the cell, such as the permeability of a membrane or the activation of another molecule. The normal reaction is to cause molecules of cyclic adenosine monophosphate (cAMP) to be synthesized from adenosine triphosphate (ATP) present in the cell. cAMP acts as secondary messenger inside the cell, where it binds to a second receptor to change physiological functions cells.

Lipid-containing endocrine hormones.
Fat-soluble hormones include steroid hormones such as testosterone, estrogen, glucocorticoids, and mineralocorticoids. Since they are fat soluble, these can pass directly through the phospholipid bilayer of the plasma membrane and bind directly to receptors within the cell nucleus. Lipids are able to directly control cell function from hormone receptors, often causing certain genes to be transcribed into DNA to produce "messenger RNA (mRNA)" that is used to produce proteins that affect cell growth and function.

There are many organs and systems in our body, in fact it is unique natural mechanism. To study the human body completely, you need a lot of time. But it's not that hard to get a general idea. Especially if it is necessary to understand any of your illnesses.

internal secretion

The word "endocrine" itself comes from the Greek phrase and means "to secrete inside." This system human body normally provides us with all the hormones that we may need.

Thanks to the endocrine system, many processes take place in our body:

• growth, comprehensive development:
• metabolism;
• power generation;
• coordinated work of all internal organs and systems;
• correction of some violations in the processes of the body;
• generation of emotions, behavior control.

The importance of hormones is enormous

Already at the moment when a tiny cell begins to develop under the heart of a woman - future child It is the hormones that regulate this process.

We literally need the formation of these compounds for everything. Even to fall in love.

What is the endocrine system made of?

The main organs of the endocrine system are:

• thyroid and thymus glands;
• epiphysis and pituitary gland;
• adrenal glands;
• pancreas;
• testicles in men or ovaries in women.

All these organs (glands) are united endocrine cells. But in our body, in almost all tissues, there are individual cells that also produce hormones.

To distinguish between united and scattered secretory cells, the overall human endocrine system is divided into:

• glandular (it includes endocrine glands)
• diffuse (in this case we are talking about individual cells).

What are the functions of the organs and cells of the endocrine system?

The answer to this question is in the table below:

1. It describes the "zone of responsibility" of the main endocrine glands, that is, glandular ES organs.
2. The organs of the diffuse endocrine system perform their own functions, and along the way, the endocrine cells in them are busy producing hormones. These organs include the stomach, spleen, intestines and. In all these organs, various hormones are formed that regulate the activity of the "owners" themselves and help them interact with the human body as a whole.

It is now known that our glands and individual cells produce about thirty different types of hormones. All of them are released into the blood in different quantities and at different intervals. In fact, it is only thanks to hormones that we live.

Endocrine system and diabetes

If the activity of any endocrine gland is disturbed, then various diseases occur.

All of them affect our health and life. In some cases, improper production of hormones literally changes the appearance of a person. For example, without growth hormone, a person looks like a dwarf, and a woman without the proper development of germ cells cannot become a mother.

The pancreas is designed to produce the hormone insulin. Without it, the breakdown of glucose in the body is impossible. In the first type of the disease, insulin production is too low, and this disrupts normal metabolic processes. The second type of SD means that internal organs literally refuse to take insulin.

Violation of glucose metabolism in the body triggers many dangerous processes. Example:

1. The body does not break down glucose.
2. To search for energy, the brain gives a signal to break down fats.
3. During this process, not only the necessary glycogen is formed, but also special compounds - ketones.

The human body is made up of several systems right action which it is impossible to imagine the usual life. one of them, because it is responsible for the timely production of hormones, which directly affect the error-free operation of all organs in the body.

Its cells secrete these substances, which are then released into the circulatory system or penetrate into neighboring cells. If you know the organs and functions of the human endocrine system and its structure, then you can maintain its normal operation and correct all problems on initial stages birth, so that man may live a long and healthy life without worrying about anything.

What is she responsible for?

In addition to regulating the proper functioning of organs, endocrine system responsible for the optimal well-being of a person during adaptation to different kind conditions. And also it is closely connected with the immune system, which makes it the guarantor of the body's resistance to various diseases.

Based on its purpose, we can distinguish the main functions:

• provides comprehensive development and growth;
• influences a person's behavior and generates his emotional state;
• responsible for the correct and accurate metabolism in the body;
• corrects some violations in the activity of the human body;
• affects the production of energy in a mode suitable for life.

The importance of hormones in the human body cannot be underestimated. The very origin of life is controlled by hormones.

Types of the endocrine system and features of its structure

The endocrine system is divided into two types. The classification depends on the placement of its cells.

• glandular - cells are placed and connected together, forming;
• diffuse - cells are distributed throughout the body.

If you know the hormones produced in the body, then you can find out which glands are associated with the endocrine system.

These can be both independent organs and tissues that belong to the endocrine system.

• hypothalamic-pituitary system - the main glands of the system are the hypothalamus and pituitary gland;
• thyroid gland - the hormones it produces store and contain iodine;
• - are responsible for optimal content and the production of calcium in the body so that the nervous and motor systems work smoothly;
• adrenal glands - they are located at the upper poles of the kidneys and consist of an outer cortical layer and an inner medulla. The cortex produces mineralocorticoids and glucocorticoids. Mineralocorticoids regulate ion exchange and maintain electrolytic balance in cells. Glycocorticoids stimulate protein breakdown and carbohydrate synthesis. The medulla produces adrenaline, which is responsible for the tone of the nervous system. The adrenal glands also produce a small amount male hormones. If a failure occurs in the girl's body and their productivity increases, there is an increase in male characteristics;
• the pancreas is one of the largest glands that produces hormones of the endocrine system and is distinguished by a paired action: it secretes pancreatic juice and hormones;
• - in endocrine function This gland secretes melatonin and norepinephrine. The first substance affects blood circulation and the activity of the nervous system, and the second regulates sleep phases;
• gonads are sex glands that are part of endocrine apparatus person, they are responsible for puberty and activity of each person.

Diseases

Ideally, absolutely all organs of the endocrine system should function without failures, however, if they happen, then a person develops specific diseases. They are based on hypofunction (dysfunction of the endocrine glands) and hyperfunction.

All diseases are accompanied by:

• the formation of the resistance of the human body to active substances;
• improper production of hormones;
• production of an abnormal hormone;
• failure of their absorption and transportation.

Any failure in the organization of the organs of the endocrine system has its own pathologies that require the necessary treatment.

• - Excess secretion of growth hormone provokes excessive, however, proportional human growth. In adulthood, only certain parts of the body grow rapidly;
• hypothyroidism - low hormone levels are accompanied by chronic fatigue and slowdown metabolic processes;
• - excess parahormone provokes poor absorption of certain trace elements;
• diabetes - when there is a lack of insulin, this disease is formed, which causes poor absorption necessary for the body substances. Against this background, glucose is poorly broken down, which leads to hyperglycemia;
• hypoparathyroidism - characterized by seizures and convulsions;
• goiter - due to lack of iodine is accompanied by dysplasia;
• autoimmune thyroiditis - the immune system does not function in the mode that it should, so it goes pathological change in tissues;
• Thyrotoxicosis is an excess of hormones.

If a endocrine organs and fabrics are malfunctioning, then apply hormone therapy. Such treatment effectively relieves the symptoms associated with hormones, and performs their functions for some time until stabilization of hormone secretion occurs:

• fatigue;
• constant thirst;
• muscle weakness;
• frequent urge to empty the bladder;
• a sharp change in body mass index;
• constant sleepiness;
• tachycardia, pain in the heart;
• increased excitability;
• decrease in memorization processes;
• excessive sweating;
• diarrhea;
• temperature increase.

Prevention

In order to prevent, anti-inflammatory and strengthening drugs are prescribed. Radioactive iodine is used. They solve many problems, although surgery is considered the most effective, doctors rarely resort to this method.

Balanced food, good physical activity, the absence of any unhealthy habits and the avoidance of stressful situations helps keep the endocrine system in good shape. Good natural conditions for life also play a huge role in avoiding diseases.

If there are any problems, you should definitely contact a specialist. Self-medication in this case is not allowed, because it can provoke complication and further development diseases. This process adversely affects the entire endocrine system.

Let's list them in order from head to toe. So, the endocrine system of the body includes: the pituitary gland, the epiphysis, the thyroid gland, the thymus (thymus gland), the pancreas, the adrenal glands, as well as the sex glands - the testicles or ovaries. Let's say a few words about each of them. But first, let's clarify the terminology.

The fact is that science distinguishes only two types of glands in the body - endocrine and exocrine. That is, the glands of internal and external secretion - because that is how they are translated from Latin these names. Exocrine glands include, for example, sweat glands coming out in the pores! on the surface of the skin.

In other words, the exocrine glands of the body secrete the secretion produced on the surfaces in direct contact with environment. As a rule, the products of their production serve to bind, contain, and then remove molecules of potentially dangerous or useless substances. In addition, the layers that have fulfilled their purpose are eliminated by the body itself - as a result of the renewal of the cells of the outer cover of the organ.

As for the endocrine glands, they completely produce substances that serve to start or stop processes inside the body. The products of their secretion are subject to constant and complete use. Most often with the decay of the original molecule and its transformation into a completely different substance. Hormones (the so-called secretion products of the endocrine glands) are always in demand in the body because, when used for their intended purpose, they break down to form other molecules. That is, not a single hormone molecule can be reused by the body. Therefore, the endocrine glands should normally work continuously, often with an uneven load.

As you can see, in relation to the endocrine system, the body has a kind of conditioned reflex. An excess or, conversely, a deficiency of any hormones is unacceptable here. In itself, fluctuations in the level of hormones in the blood are quite normal. It all depends on what process needs to be activated now and how much it needs to be done. The decision to stimulate or suppress any process is made by the brain. More precisely,* the neurons of the hypothalamus surrounding the pituitary gland. They give a "command" to the pituitary gland, and he begins, in turn, "to manage" the work of the glands. This system of interaction between the hypothalamus and the pituitary gland is called in medicine hypothalamic-pituitary.

Naturally, situations in a person's life are different. And all of them affect the state and work of his body. And for the reaction and behavior of the body in certain circumstances, the brain is responsible - more precisely, its cortex. It is he who is designed to ensure the safety and stability of the state of the body under any external conditions. This is the essence of his daily work.

Yes, during the period prolonged fasting the brain must take a number of biological measures that would allow the body to wait out this time with minimal losses. And during periods of saturation, on the contrary, he must do everything so that the food is assimilated most fully and quickly. Therefore, a healthy endocrine system is able, so to speak, to release huge single doses hormones. And tissue brushes, in turn, have the ability to absorb these stimulants in unlimited quantity. Without this combination effective work endocrine system loses its main meaning.

If now we understand why a single overdose of a hormone is an impossible phenomenon in principle, let's talk about the hormones themselves and the glands that produce them. Inside the brain tissue are two glands - the pituitary and pineal glands. Both are located within the midbrain. The pineal gland is in its part, which is called the epithalamus, and the pituitary gland is in the hypothalamus.

epiphysis produces mainly corticosteroid hormones. That is, hormones that control the activity of the cerebral cortex. Moreover, the hormones of the pineal gland regulate the degree of its activity depending on the time of day. The tissues of the pineal gland contain special cells - pinealocytes. The same cells are found in our skin and retina. Their main purpose is to record and transmit to the brain information about the level of illumination outside. That is, the amount of light that falls on them at a given time. And pinealocytes in the tissues of the pineal gland serve this gland so that it itself can alternately increase the synthesis of either serotonin or melatonin.

Serotonin and melatonin are the two main hormones of the pineal gland. The first is responsible for the concentrated, uniform activity of the cerebral cortex. It stimulates attention and thinking is not stressful, but, as it were, normal for the brain during wakefulness. As for melatonin, it is one of the sleep hormones. Thanks to him, the speed of passage of impulses along nerve endings decreasing, many physiological processes slow down and the person tends to sleep. Thus, the periods of wakefulness and sleep of the cerebral cortex depend on how accurately and correctly the pineal gland distinguishes the time of day.

Pituitary, as we have already found out, performs much more functions than the pineal gland. In general, this gland itself produces more than 20 hormones for various purposes. Due to the normal secretion of all its substances by the pituitary gland, it can partially compensate for the functions of the glands of the endocrine system subordinate to it. With the exception of the thymus and islet cells in the pancreas, since these two organs produce substances that the pituitary gland cannot synthesize.

Plus, with the help of the products of its own synthesis, the pituitary gland still has time, so to speak, to coordinate the activity of the rest of the endocrine glands of the body. Processes such as peristalsis of the stomach and intestines, hunger and thirst, heat and cold, the metabolic rate in the body, the growth and development of the skeleton, puberty, the ability to conceive, the rate of blood clotting, etc., depend on its proper operation, etc.

Persistent dysfunction of the pituitary gland leads to large-scale disorders throughout the body. In particular, due to damage to the pituitary gland, it is possible to develop diabetes, which in no way depends on the state of the pancreatic tissues. Or chronic digestive dysfunction with initially perfectly healthy gastrointestinal tract Injuries to the pituitary gland significantly increase the clotting time of some blood proteins.

Next on our list thyroid. It is located in the upper front of the neck, right under the chin. The thyroid gland is much more butterfly shaped than a shield. Because it is formed, like most glands, by two large lobes connected by an isthmus of the same tissue. The main purpose of the thyroid gland is to synthesize hormones that regulate the rate of metabolism of substances, as well as the growth of cells in all tissues of the body, including bone.

In most cases, the thyroid gland produces hormones formed with the participation of iodine. Namely, thyroxine and its more active modification from a chemical point of view - triiodothyronine. In addition, some thyroid cells ( parathyroid glands) synthesizes the hormone calcitonin, which serves as a catalyst for the reaction of bone absorption of calcium and phosphorus molecules.

thymus located slightly lower - behind the flat sternum, which connects two rows of ribs, forming our chest. The thymus lobes are under top sternum - closer to the collarbones. Or rather, where the common larynx begins to bifurcate, turning into the trachea of ​​the right and left lungs. This endocrine gland is an indispensable part of the immune system. It does not produce hormones, but special bodies of immunity - lymphocytes.

Lymphocytes, unlike leukocytes, are transported to tissues through the lymphatic rather than the bloodstream. Another important difference between thymus lymphocytes and bone marrow leukocytes is their functional purpose. Leukocytes are not able to penetrate into the tissue cells themselves. Even if they are infected. Leukocytes are only able to recognize and destroy pathogens whose bodies are located in the intercellular space, blood and lymph.

For the timely detection and destruction of infected, old, incorrectly formed cells, it is not white blood cells that are responsible, but lymphocytes, which are produced and trained in the thymus. It should be added that each type of lymphocyte has its own non-strict, but obvious "specialization". So, B-lymphocytes serve as a kind of indicators of infection. They detect the pathogen, determine its type and trigger the synthesis of proteins directed specifically against this invasion. T-lymphocytes regulate the speed and strength of the immune system's response to infection. And NK-lymphocytes are indispensable in cases when it is necessary to remove cells from tissues that are not infected, but defective, exposed to radiation or the action of toxic substances.

Pancreas located where indicated< в ее названии, - под сфинктером желудка, у начал а small intestine. In its main purpose, it produces digestive enzymes small intestine. However, in the array of its tissues there are inclusions of cells of a different type, which produce the well-known hormone insulin. It was named insulin because the clusters of cells that produce it resemble islets in appearance. And in translation from Latin, the word insula means "island".

It is known that all substances that come with food are broken down in the stomach and intestines into glucose molecules - the main source of energy for any body cell.

Assimilation of glucose by cells is possible only in the presence of insulin. Therefore, if there is a deficiency of this pancreatic hormone in the blood, a person eats, but his cells do not receive this food. This phenomenon is called diabetes mellitus.

Next: down we have the adrenal glands. If the kidneys themselves act as the main filters of the body and synthesize urine, then the adrenal glands are fully occupied with the production of hormones. Moreover, in terms of the direction of action, the hormones produced by the adrenal glands largely duplicate the work of the pituitary gland. Thus, the body of the adrenal glands is one of the main sources of stress hormones - dopamine, norepinephrine and adrenaline. And their bark is a source of corticosteroid hormones aldosterone, cortisol (hydrocortisone) and corticosterone. Among other things, in the body of each person, the adrenal glands synthesize a nominal amount of hormones of the opposite sex. Women have testosterone and men have estrogen.

And finally gonads. Their main purpose is obvious, and it consists in the synthesis enough sex hormones. Sufficient for the formation of an organism with all the signs of its gender and for further uninterrupted operation of the reproduction system. The difficulty here lies in the fact that in the body of both men and women, hormones of not one, but of both sexes are simultaneously produced. Only the main hormonal background is formed due to the work of the sex glands of the corresponding type (ovaries or testes), and the secondary one is due to the much lower activity of other glands.

For example, in women, testosterone is produced primarily in the adrenal glands. And estrogen in men is in the adrenal glands and body fat. The ability of fat cells to synthesize substances resembling hormones in properties was discovered relatively late - in the 1990s. Until that time, adipose tissue was considered an organ that takes a minimal part in metabolism. Their role was assessed by science very simply - fat was considered a place of accumulation and storage of female sex hormones estrogen. This explains the high percentage of fatty tissues in a woman's body compared to men.

At present, the understanding of the biochemical role of adipose tissues in the body has expanded significantly. This happened due to the discovery of adipokines - hormone-like substances that synthesize fat cells. There are a lot of these substances, and their study has just begun. Nevertheless, it is already safe to say that among the adipokines there are substances that can increase the resistance of body cells to the action of the body's own insulin.

So, we already know that the endocrine system of the body includes seven endocrine glands. And, as we ourselves could see, there are strong relationships between them. Most of these relationships are formed by two factors. The first is that the work of all endocrine glands is coordinated and controlled by a common analytical center - the pituitary gland. This gland is located inside the tissues of the brain, and its work, in turn, is regulated by this particular organ. The latter becomes feasible due to the presence of a separate system of connections between the neurons of the hypothalamus and the cells of the pituitary gland, which is called the hypothalamic-pituitary.

And the second factor lies in the effect of duplication of the functions of many glands with each other, which we have clearly demonstrated. So, for example, the same pituitary gland not only regulates the activity of all elements of the endocrine system, but also synthesizes most of the same substances as they do. Similarly, the adrenal glands produce a number of hormones, which will be quite enough to continue the work of the cerebral cortex. Including when complete failure both pituitary and epiphyseal. Similarly, the adrenal glands are able to change the content of the main hormonal background body in case of failure of the sex glands. This will happen due to their ability to produce hormones of the opposite sex.

As mentioned above, an exception in this system of mutually conditioned connections are two glands - the thymus and special cells in the pancreas that produce insulin. However, there are no really strict exceptions here. Thymus-produced lymphocytes are a very important part of immune protection organism. Nevertheless, we understand that we are talking about only part of immunity, and not about it as a whole. With regard to islet cells, in fact, the mechanism for the absorption of sugar with the help of insulin in the body is not the only one. The liver and brain are organs that are able to absorb glucose even in the absence of this hormone. The only "but" is that the liver can only process a slightly different chemical modification of glucose, called fructose.

Thus, in the case of the endocrine system, the main difficulty is that most pathologies and medical effects simply cannot affect only one target organ. This is impossible because both similar cells in other glands and the pituitary gland, which fixes the level of each of the hormones in the patient's blood, will necessarily respond to such an impact.