Hormones are things organic nature, affecting metabolic processes, the work of tissues and organs, the growth of the body. They are produced in humans by endocrine glands, enter the blood or lymph and are delivered to target cells, which are affected.
glands
They are called endocrine (internal secretion), because they do not have ducts to the outside, their secret (hormones) remains inside the body. They regulate each other's work and are able to speed up or slow down the rate of hormone production, thereby affecting the work of all organs and tissues. We can say that they support the entire vital activity of the body. The endocrine glands include:
They perform various functions.
Pituitary and hypothalamus
This system is located in the back of the brain, despite its small size(only 0.7 gr.), She is the "head" of the whole. Most of hormones produced by the pituitary gland regulates the work of other glands. The hypothalamus acts as a “sensor”, picking up brain signals about fluctuating levels of other hormones, and sending a “command” to the pituitary gland that it is time to start working. Previously, it was also considered a full-fledged gland that affects the functioning of the body, but thanks to research, it was found that hormones are secreted by the pituitary gland, and the hypothalamus regulates these functions through releasing hormones. There are two types of them: some start the secretion process (release), others slow down (stop). The pituitary hormones include:
Thyroid and parathyroid glands
The thyroid gland is located in the region of the upper third of the trachea, attached to it by connective tissue, has two lobes and an isthmus, resembling an inverted butterfly in shape. Its average weight is about 19 grams. secretes thyroid thyroid hormones: thyroxine and triiodothyronine, which are involved in cell metabolism and energy metabolism. Maintaining human body temperature, maintaining the body during times of stress and physical activity, receiving cells of water and nutrients, the formation of new cells - all this is the activity of thyroid hormones.
On the back wall thyroid gland located, small (no more than 6 g.) parathyroid glands. Most often, a person has two pairs of them, but sometimes it happens less, which is considered a variant of the norm. They produce hormones that regulate the level of calcium in the blood - paratin. They act in tandem with calcitonin, a thyroid hormone that lowers calcium levels, and they increase it. 
This is an unpaired small organ located between the hemispheres in the center of the brain. Its shape resembles a pine cone, for which it received its second name - the pineal gland. Weight is only 0.2 g. The activity of this gland depends on the illumination of the place where the person is located. His leashes are attached to the optic nerves, through which he receives signals. It produces serotonin in the light and melatonin in the dark.
Serotonin also performs the role of a neurotransmitter - a substance that promotes the transmission of impulses between neurons, thanks to this property it improves a person's mood, restrains pain impulses, and is responsible for muscle activity.
Once in the blood, it performs the functions of a hormone: it affects the development inflammatory processes and blood clotting, slightly allergic reactions and regulates the hypothalamus.
Melatonin - a hormone derived from serotonin, is responsible for blood pressure, falling asleep and the depth of sleep, activates the immune system, inhibits synthesis growth hormone, reducing the risk of developing tumors, controls puberty and sexual arousal. During sleep, he restores damaged cells and slows down the aging process. Because healthy good dream so important to a person.
The pineal gland produces another hormone - adrenoglomerulotropin, its functions are not yet clear, scientists managed to find out that it affects the secretion of hormones by the adrenal medulla, but the whole process remains a mystery to them.
It is located behind the sternum, is a paired organ weighing about 20 grams. It grows until puberty, then begins to slowly atrophy, in older people it is almost indistinguishable from adipose tissue. The thymus is an important organ immune system, in which T-cells mature, differentiate and immunologically “learn”. It produces hormones
- Timalin;
- Thymosin;
- Thymopoietin;
- IGF-1;
Its role for the body is still not well understood. But its most important function is to prevent a person from dying in childhood from infections. It works hard in babies, producing T-lymphocytes, endowing them with T-cell receptors and co-receptors (markers), forming acquired immunity. It is thanks to the thymus that a person does not get sick twice with diseases caused by measles viruses, chicken pox, rubella and many others.
They are located above each of the human kidneys, the weight of one is about 4 g, 90% of the gland is the adrenal cortex, the remaining 10% is the medulla. They produce various groups hormones:
- Mineralocorticoids (water-salt balance);
- Glucocorticoids (glucose formation, anti-shock effect, immunoregulation, anti-allergic effect);
- Androgens (synthesis and breakdown of proteins, utilization of glucose, lowering the level of cholesterol and lipids in the blood, reducing the amount of subcutaneous fat);
- Catecholamines (support the body during fear, rage, physical exertion, giving a signal to the hypothalamus, enhance the work of other glands);
- Peptides (cell regeneration, removal of toxins, increases the wear resistance of tissues).
It is located in the epigastric region, behind the stomach. Endocrine functions are performed only by a small part of it - the pancreatic islets. They are not located in one place, but are scattered unevenly throughout the gland. They secrete several hormones:
- Glucagon (increases blood glucose levels);
- Insulin (transportation of glucose into cells).
Most of the pancreas produces gastric juices performing an exocrine function. 
gonads
The sex glands include the testicles and ovaries, they, like the pancreas, are mixed glands, performing intrasecretory and exocrine functions.
Ovaries - paired female glands, are located in the cavity of the small pelvis, weight is about 7 grams. They produce steroid hormones: estrogens, gestagens, androgens. They provide ovulation and the formation of the corpus luteum after conception. Their concentration is not constant, one of the hormones dominates, then another and a third, which creates a cycle.
The testicles are also a paired organ, male, glands are located in the scrotum. The main testicular hormone is testosterone.
The gonads are responsible for the development of the reproductive organs and the maturation of the egg and sperm. They form secondary sexual characteristics: voice timbre, skeletal structure, location of body fat and hairline, affect mental behavior Everything that separates men from women.
All processes occurring in our body are regulated by the nervous and humoral systems. significant role in the regulation physiological functions organism plays hormonal system operating through chemical substances through body fluids (blood, lymph, intercellular fluid). The main organs are systems - the pituitary gland, thyroid gland, adrenal glands, pancreas, gonads.
There are two types glands. Some of them have ducts through which substances are released into the body cavity, organs or onto the surface of the skin.
They are called glands of external secretion. External secretion glands are lacrimal, sweat, salivary, gastric glands, glands that do not have special ducts and secrete substances into the blood flowing through them are called endocrine glands. These include the pituitary gland, thyroid gland, thymus gland, adrenal glands and others.
Hormones– biologically active substances. Hormones are produced in small amounts, but long time remain in an active state and are carried throughout the body with the blood stream.
Endocrine glands:
Pituitary. Situated at the base. A growth hormone. It has a great impact on the growth of a young organism.
adrenal glands. Paired glands adjacent to the apex of each kidney. Hormones - norepinephrine, adrenaline. Regulates water-salt, carbohydrate and protein metabolism. Stress hormone, control of muscle activity, cardiovascular system.
Thyroid. It is located on the neck in front of the trachea and on the side walls of the larynx. The hormone is thyroxine. regulation of metabolism.
Pancreas. Located under the stomach. The hormone is insulin. Plays an important role in carbohydrate metabolism.
gonads. Male testes are paired organs located in the scrotum. Women's - ovaries - in abdominal cavity. Hormones - testosterone, female hormones. Participates in the formation of secondary sexual characteristics in organisms.
With a lack of growth hormone produced, dwarfism occurs, with hyperfunction - gigantism. With hypofunction of the thyroid gland in adults, mexedema occurs - metabolism is reduced, body temperature drops, the rhythm of heart contractions is weakened, and the excitability of the nervous system decreases. In childhood, cretinism is observed (one of the forms of dwarfism), physical, mental and sexual development. Lack of insulin leads to diabetes. With an excess of insulin, the level of glucose in the blood drops sharply, this is accompanied by weakness, hunger, loss of consciousness and convulsions.
Endocrine glands, or endocrine glands, are those glands that do not have excretory ducts and secrete physiologically active substances (hormones) directly into the internal environment of the body -. Together with the nervous endocrine system, it ensures that the body adapts to environmental conditions. But if the nervous system is structurally rigidly organized, then hormones, moving with the blood, act on all organs and where they can contact specific hormone receptors. If the nervous system exercises its influences almost instantly, then the endocrine system develops its effects on the body more slowly, but their duration, unlike the nervous ones, can be very significant.
Hormones are substances of various classes (amino acids and their derivatives, peptides, steroids, etc.), which are usually produced and secreted by specialized glands. Although, for example, many hormones are synthesized in the hypothalamic region of the diencephalon. So the hypothalamus is a neuroendocrine organ. All activities endocrine system is under the control of the nervous system, although the nervous system is constantly controlled by the endocrine system.
A substance that belongs to hormones must meet the following criteria: be isolated from living cells, and without violating their integrity; not serve as a source of energy; released into the blood in very small quantities; enter directly into the blood; act on target organs through specific receptors.
Some hormones have a direct regulatory effect on some organ, while others may have a programming effect, i.e. at a certain moment, they change the cells of any tissues for the entire subsequent time of their life.
Receptors for hormones are proteins. Some of them are located on the outer membrane of the cell, and when a hormone molecule binds to such a receptor, a whole cascade of chemical changes is triggered in the cell, and its state changes. This mechanism of action is usually possessed by proteinaceous peptide hormones. This type of reception is called membrane. Another type of reception is nuclear. Hormones with such a reception (for example, steroids) must get inside the cell, pass into its nucleus and there affect the genetic apparatus of the cell, inducing or inhibiting the synthesis of some proteins. The effects of hormones with nuclear reception develop slowly, but they persist for a very long time.
Pituitary
The pituitary gland is a lower cerebral appendage connected to the hypothalamus by a thin stalk. The mass of the pituitary gland is about 0.5 g. It is located in a special bone recess - the Turkish saddle. Anatomically and functionally, the pituitary gland is divided into three lobes: anterior, intermediate, and posterior. In the anterior lobe of the pituitary gland, peptide hormones are synthesized and released into the bloodstream that control the activity of others. endocrine glands.
Hormones of the anterior pituitary gland. Adrenocorticotropic hormone (corticotropin, ACTH) stimulates the activity of the adrenal cortex. In turn, the release of ACTH is controlled by corticoliberin, a peptide produced in the hypothalamus. With an excess of ACTH, Cushing's syndrome develops: the adrenal cortex grows, obesity occurs, headaches, hysteria appear, etc.
Thyroid-stimulating hormone (TSH) stimulates the synthesis of thyroid hormones. The release of TSH is controlled by thyroliberin, a peptide that is produced in the hypothalamus.
Gonadotropins (luteinizing and follicle-stimulating hormones) control the activity of the gonads. They enhance the formation of male and female sex hormones in the testes and ovaries, stimulate the growth of the testes, the growth of follicles. The synthesis and release of gonadotropins is controlled by luliberin, a peptide that is produced in the hypothalamus.
Somatotropic hormone (growth hormone) does not act on any one endocrine gland, but stimulates the production of tissue growth factors in the cells of many tissues. In turn, these tissue factors stimulate the growth of all parts of the body. With a lack of somatotropic hormone, pituitary dwarfism develops in children, and with an excess, pituitary gigantism develops. If an excess of somatotropic hormone is observed in an adult, when normal growth has already stopped, then a disease occurs - acromegaly, in which the nose, lips, fingers and toes grow. The production of somatotropin is regulated by peptides of the hypothalamus: stimulated by somatoliberin, and inhibited by somatostatin.
Prolactin stimulates the production of milk in nursing mothers and is involved in organizing the activity of the gonads.
In the intermediate lobe of the pituitary gland, a melanocystimulating hormone is produced, the functions of which have not been studied enough, but it has been shown that its excess increases skin pigmentation and it noticeably darkens.
The hormones of the posterior pituitary gland - vasopressin (antidiuretic hormone - ADH) and oxytocin - are peptides and are similar in chemical structure. They are produced in the neurons of the hypothalamus, and then descend along the leg into the posterior lobe of the hypothalamus and from there can enter the bloodstream. The main function of vasopressin is to increase reabsorption in the renal tubules, which leads to a decrease in urine volume. This hormone takes an important part in the regulation of the constancy of the internal environment of the body, and with its shortage, a person develops a disease - not diabetes in which the body loses a large number of water and some salts. Oxytocin stimulates contraction of the smooth muscles of the vas deferens and oviducts, and also plays a critical role in childbirth by stimulating uterine muscle contraction.
Thyroid
The thyroid gland is located on the anterior wall of the larynx, consists of two lobes and an isthmus and has a mass of 25 to 40 g. Outside, the gland is covered with a connective tissue membrane. The gland itself is formed by special vesicles - follicles, in which hormones containing iodine are produced - thyroxine (tetraiodothyronine) and triiodothyronine. Thyroid hormones perform a number of functions. Firstly, they are programming, participating, for example, in the puberty of various animals and humans. If the tadpole of a frog is deprived of these hormones, it will grow to a gigantic size, but it will not be able to turn into a frog. Secondly, these hormones increase the metabolism, stimulating cellular respiration, increase the secretion of growth hormone from the pituitary gland. Thirdly, thyroid hormones increase the production of heat by the body - thermogenesis. Diseases associated with disorders of the thyroid gland can occur not only with changes in the gland itself, but also with a lack of iodine in the body, diseases of the anterior pituitary gland, etc.
With a decrease in thyroid function in childhood, cretinism develops, characterized by inhibition in the development of all body systems, short stature, and dementia. In an adult with a lack of thyroid hormones, myxedema occurs, in which edema, dementia, decreased immunity, and weakness are observed. This disease responds well to treatment with thyroid hormones administered externally. When the activity of the thyroid gland is increased, Graves' disease, in which excitability, metabolism, heart rate increase sharply, bulging eyes (exophthalmos) and weight loss are characteristic.
In those geographical areas, where it contains little iodine (usually found in the mountains), goiter is often observed in the population - a disease in which the secreting tissue of the thyroid gland grows, but cannot synthesize full-fledged hormones in the absence of the required amount of iodine. In such areas, the consumption of iodine by the population should be increased, which can be ensured, for example, by selling table salt with obligatory small additions of sodium iodide.
parathyroid glands
Parathyroid glands are small glands located on the surface or in the thickness of the thyroid gland, usually two on each side. They secrete parathyroid hormone, which regulates calcium metabolism in the body. When these glands are affected, there is a lack of calcium ions in the blood, convulsions, vomiting and death against the background of paralysis of the respiratory muscles. At increased function bones begin to lose Ca 2+, muscle weakness occurs. At the same time, the level of Ca 2+ in the blood plasma increases.
Pancreas
The pancreas has a mixed secretion: some of its cells secrete a number of digestive enzymes through the ducts into duodenum(external secretion), while clusters of other cells called the islets of Langerhans release the hormones insulin and glucagon directly into the blood. The continuous release of insulin into the blood is necessary so that the main source of energy - glucose - can freely pass from the blood plasma to the tissues, and its excess is deposited in the liver in the form of a glycogen polymer. With a lack of insulin, diabetes mellitus develops - a disease in which glucose does not penetrate into the tissues, and its level in the blood plasma increases greatly, which entails the excretion of glucose from the body in large volumes of urine. If a diabetic patient is not administered insulin from outside, then depriving the brain of glucose leads to loss of consciousness, convulsions and rapid death. The second hormone of the pancreas - glucagon - is synthesized in special cells of the islets of Langerhans and is necessary for the formation of glucose from glycogen when there is a shortage of it in the blood plasma. Thus, insulin and glucagon, by having an opposite effect on carbohydrate metabolism, provide a precise regulation of the body's consumption of glucose.
adrenal glands
The adrenal glands are small paired glands located at the upper poles of the kidneys and consisting of two layers: cortical and medulla. The cells of the outer cortical layer produce three groups of hormones:
1) Glucocorticoids, the main of which is cortisol, stimulate the synthesis of glycogen from glucose, lower the level of glucose consumption by tissues, inhibit the immune response, and prevent inflammatory processes.
2) Mineralocorticoids (for example, aldosterone) regulate the content of Na + and K + in the body, increasing the reverse absorption of Na + in the renal tubules and stimulating the excretion of K + and H + in the urine.
3) The precursors of sex hormones, mainly male ones, are involved in the formation of secondary sexual characteristics as programming hormones.
With insufficient functioning of the adrenal cortex, Addison's disease occurs, which is characterized by carbohydrate metabolism disorders, low blood pressure, weight loss, nausea, and increased skin pigmentation.
The adrenal medulla produces adrenaline and norepinephrine and is functionally part of a single regulatory system with sympathetic department autonomic nervous system. In those periods when the body must work under great stress (in case of injury, during danger, in conditions of increased physical and mental labor, etc.), these hormones enhance muscle work, increase blood glucose (to ensure increased energy costs brain), increase blood flow in the brain and other vital important organs, increase the level of systemic blood pressure, enhance cardiac activity, etc. Thus, the hormones of the adrenal medulla serve to ensure the body's response to extreme exposure or stress response.
epiphysis
The pineal gland is a small reddish-brown gland weighing only 0.15-0.20 g, located between the upper tubercles of the quadrigemina of the midbrain in a special cranial cavity. The pineal gland is connected to the brain by a hollow stalk. So far, only one hormone of the pineal gland is known - melatonin, under the action of which the release of gonadotropic hormones, the rate of puberty changes, in animals - seasonal physiological cycles. The work of the pineal gland is sensitive to ambient light: the synthesis of melatonin in it is enhanced in the dark, it is increased in blind people.
thymus
Thymus (thymus gland) is a small lymphoid organ, consisting of two lobules and located behind the sternum in the mediastinum. The thymus is well developed only in childhood and practically disappears during puberty. The non-endocrine function of the thymus is that T-lymphocytes, which are necessary for providing immunity, mature in it, which, after maturation, populate other lymphoid organs. endocrine function thymus is that it secretes into the blood the peptide hormones thymosin and thymopoietins, which stimulate the growth and formation of the immune system. If the thymus continues to function actively in an adult, autoimmune diseases, in which, due to a pathological increase in immunity, the destruction of the body's own proteins by antibodies is observed. Such diseases include systemic lupus erythematosus, myasthenia, etc.
gonads
Sex glands (gonads) - are glands of mixed, that is, both external and internal, secretion. The sex glands of a woman - the ovaries - are secreted into external environment eggs, and in the internal - the hormones estrogens and progestins. The sex glands of a man - the testes - secrete spermatozoa into the external environment, and hormones androgens into the internal environment.
The ovaries secrete estradiol into the blood, an ovulation inducer related to estrogens, which is also involved in the formation of secondary sexual characteristics by female type(development of the mammary glands, a certain type of physique, etc.). Progesterone, related to progestins, is produced in the corpus luteum, which is formed at the site of a burst follicle. Progesterone is a hormone of pregnancy, it is necessary for the attachment (implantation) of the embryo to the wall of the uterus, and also inhibits the maturation and ovulation of follicles during pregnancy.
The testicles secrete androgens into the blood, the main of which is testosterone, which performs a number of functions. It is necessary for the normal formation of the reproductive system in the embryo male type, for the development of male secondary sexual characteristics (hair growth and muscle development according to the male type, low voice, metabolic and behavioral features, etc.), ensures the constancy of spermatogenesis, etc.
Human endocrine glands produce hormones. This is what biologically active substances are called, which have an extremely strong effect on the tissues, cells and organs to which their activity is directed. The glands got their name due to the absence of excretory ducts: they release active substances into the blood, after which hormones spread throughout the body and control its work.
The endocrine glands are divided into two groups. The first group includes organs whose activity is under the control of the pituitary gland, the second group includes glands that act independently, according to the biorhythms and rhythms of the body.
The central organ of the endocrine system, which controls the activity of almost everyone, is the pituitary gland, which consists of two parts and produces great amount different types of hormones. It is located in the bone pocket of the sphenoid bone of the skull, attached to the lower part of the brain and controls the activity of the thyroid gland, parathyroid gland, adrenal glands, sex glands.
The hypothalamus controls the work of the pituitary gland, one of the parts of the brain, closely connected not only with the endocrine, but also with the central nervous system. This gives him the opportunity to capture and correctly interpret all the processes occurring in the body, interpret them and give the pituitary a signal to increase or decrease the synthesis of certain hormones.
The hypothalamus controls the endocrine glands with hormones that are produced in the anterior pituitary gland. How do pituitary hormones affect endocrine organs can be seen in the following table:
In addition to those indicated in the table, the anterior part of the pituitary gland produces, accelerating the synthesis of proteins in cells, which affects the formation of glucose, the breakdown of fats, the growth and development of the body. Another hormone that is involved in reproductive function is prolactin.
Under its influence, milk is formed in the mammary glands, and during lactation, the onset of a new pregnancy is inhibited, since it inhibits the hormones responsible for preparing for conception. It also affects metabolism, growth, causes instincts aimed at caring for offspring.
In the second part of the pituitary gland (neurohypophysis), hormones are not produced: biologically active substances that are produced by the hypothalamus accumulate here. After hormones accumulate in the neurohypophysis in enough they pass into the blood. The best known posterior pituitary hormones are oxytocin and vasopressin.
Vasopressin controls the excretion of water by the kidneys, protecting the body from dehydration, has a vasoconstrictive effect, stopping bleeding, increases blood pressure, as well as the tone of the smooth muscles of the internal organs. He governs aggressive behavior responsible for memory.
Oxytocin stimulates contraction of the smooth muscles of the bladder, gallbladder, ureters, and intestines. The need for is especially great, since this hormone is responsible for contracting the smooth muscles of the uterus, and after the birth of the baby, the mammary glands, stimulating the supply of milk to the baby during sucking.
Epiphysis and thyroid gland
Another endocrine gland attached to the brain is the pineal gland (other names are the pineal gland, pineal gland). He is responsible for the production of neurotransmitters and hormones melatonin, serotonin, adrenoglomerulotropin.
Serotonin, as well as melatonin synthesized with its participation, are responsible for the mode of wakefulness and sleep. Melatonin slows down the aging process, serotonin has a calming effect on the nervous system. They also improve tissue regeneration, if necessary, suppress reproductive function stop the development of malignant tumors.
The thyroid gland is located on the front side of the neck, under the Adam's apple, consists of two lobes, which are connected to each other by the isthmus and covers the trachea from three sides. The thyroid gland produces iodine-containing hormones thyroxine (T4) and triiodothyronine (T3), the synthesis of which is regulated by the pituitary gland. Another thyroid hormone is calcitonin, which is responsible for the condition bone tissue and affects the kidneys, accelerating the excretion of calcium, phosphates, chlorides from the body.
Thyroxine is produced by the thyroid gland in much greater quantities than triiodothyronine, but it is a less active hormone and is subsequently converted to T3. Iodine-containing hormones are actively involved in almost all processes occurring in the body: in metabolism, growth, physical and mental development.
Excess, as well as lack of iodine-containing hormones, negatively affects the body, provokes a change in body weight, pressure, increases nervous excitability, causes lethargy and apathy, worsening mental abilities, memory . Often the cause of the development of malignant and benign tumors, goiter. Lack of T3 and T4 in childhood can provoke cretinism.
Parathyroid and thymus glands
Parathyroid or parathyroid glands are attached to the back of the thyroid gland, two to each lobe, they synthesize parathyroid hormone, which ensures that calcium in the body is within normal limits, ensuring the proper functioning of the nervous and motor systems. It affects the bones, kidneys, intestines, has a positive effect on blood clotting, is involved in the exchange of calcium and phosphorus.
Lack of parathyroid hormone, as well as if parathyroid glands were removed, causes frequent and very strong convulsions, increases nervous excitability. A severe illness can lead to death.
The thymus (another name is the thymus gland) is located in the middle of the upper part chest person. It belongs to the glands mixed type, since the thymus not only synthesizes hormones, but is also responsible for immunity. T-cells of the immune system are formed in it, the task of which is to suppress the auto-aggressive cells that the body, for some reason, begins to produce to destroy healthy cells. Another challenge thymus is the filtration of blood and lymph passing through it.
Also, under the control of cells of the immune system and the adrenal cortex, the thymus synthesizes hormones (thymosin, thymalin, thymopoietin, etc.), which are responsible for immune and growth processes. Damage to the thymus gland entails a decrease in immunity, the development cancerous tumors, autoimmune or serious infectious diseases.
Pancreas
Is not only an organ digestive system, which secretes pancreatic juice containing digestive enzymes, but is also considered an endocrine gland, since it produces hormones to regulate fat, protein, carbohydrate metabolism. Among the biologically active substances that the pancreas produces, highest value have hormones that are synthesized in the islets of Langerhans.
Alpha cells produce glucagon, which converts glycogen into glucose. Beta cells secrete the hormone insulin, whose task is to control the amount of glucose: when its level begins to exceed the norm, it converts it into glycogen. Thanks to insulin, cells have the ability to evenly absorb glucose, while glycogen accumulates in the muscles and liver.
If the pancreas does not cope with its duties and does not produce insulin in the right amount, sugar ceases to be converted into glycogen and diabetes mellitus develops. As a result, the metabolism of proteins and fats is disturbed, the digestibility of glucose worsens. If the disease is not treated, a person can fall into a hypoglycemic coma and die.
An excess of the hormone is no less dangerous, since the cells are oversaturated with glucose, which leads to a decrease in the amount of sugar in the blood, to which the body reacts accordingly and sets in motion mechanisms aimed at increasing glucose, contributing to the development of diabetes.
The role of the adrenal glands in the body
The adrenal glands are two glands located above the kidneys, each of which consists of a cortex and a medulla. , which are synthesized in the medulla, are adrenaline and norepinephrine, which are required to ensure a timely response of the body to dangerous situation, bring all body systems to full readiness and overcome the obstacle.
The adrenal cortex consists of three layers, and the hormones it produces are controlled by the pituitary gland. The influence of biologically active substances that the cortex produces on the body can be seen in the following table:
| Where is produced | Hormone | Action |
| tangle zone | Aldosterone, corticosterone, deoxycorticosterone | They control water-salt metabolism, contributing to an increase in systemic blood pressure and blood volume. |
| beam zone | corticosterone, cortisol | Control protein and carbohydrate metabolism; Reduce the synthesis of antibodies; They have anti-inflammatory, anti-allergic effects, strengthen the immune system; maintain the amount of glucose in the body; contribute to the formation and deposition of glycogen in the muscles and liver. |
| mesh zone | estradiol, testosterone, androstenedione, degyroepiandrosterone sulfate, degyroepiandrosterone |
The sex hormones that the adrenal glands produce affect the formation even before the onset of puberty. |
Violations in can provoke the development of the most various diseases ranging from bronze disease to malignant tumors. Characteristic features diseases of the endocrine glands is a bronze hue (pigmentation) of the skin, constant fatigue weakness, problems with blood pressure, digestive system.
Functions of the sex glands
The main purpose of biologically active substances that are produced in the sex glands is to stimulate the development reproductive organs maturation of eggs and spermatozoa. They also play an important role in the formation of secondary sexual characteristics that distinguish women from men (the structure of the skull, skeleton, voice timbre, subcutaneous fat, psyche, behavior).
The testicles or seminal glands in men are a paired organ, inside which spermatozoa develop. Here, male sex hormones are synthesized, primarily testosterone. Inside the female ovaries are follicles. When the next one starts menstrual cycle, the largest of which is influenced by hormone FSH begins to grow, and inside it - to mature the egg.
During growth, the follicle begins to actively produce the main sex hormones responsible for the preparation female body to conception and childbirth - estrogens (estradiol, estrone, estriol). After ovulation, at the site of the ruptured follicle, corpus luteum, which begins to actively produce progesterone. To prepare the body for pregnancy, the female sex glands produce androgens, inhibin, and relaxin.
The relationship of the endocrine glands
All endocrine glands are closely related to each other: the hormones that one gland produces have a very strong influence on the biologically active substances that the other synthesizes. In some cases, they enhance their activity, in others they work on the principle of feedback, reducing or increasing the amount of hormones in the body.
This means that if one organ is damaged, for example, the pituitary gland, this will certainly be displayed on the glands under its control. They will begin to produce an insufficient or excessive amount of hormones, which will provoke the development of serious diseases.
Therefore, the doctor, suspecting the presence of problems in the endocrine system, prescribes a blood test for hormones in order to determine the cause of the disease and develop correct scheme treatment.
Full functioning human body directly depends on the work of various internal systems. One of the most important is the endocrine system.. Its normal work is based on how the human endocrine glands behave. Endocrine and endocrine glands produce hormones that are then distributed throughout internal environment human body and organize the correct interaction of all organs.
Human endocrine glands produce and secrete hormonal substances directly into the bloodstream. They do not have excretory ducts, for which they received the owl's name.
The endocrine glands include: thyroid, parathyroid glands, pituitary gland, adrenal glands.
There are a number of other organs in the human body that also release hormonal substances not only into the blood, but also into the intestinal cavity, thereby carrying out exocrine and endocrine processes. Intrasecretory and exocrine work These organs are assigned to the pancreas (digestive juices) and the glands of the reproductive system (eggs and spermatozoa). These organs of the mixed type belong to the endocrine system of the body according to generally accepted rules.
Pituitary and hypothalamus
Almost all the functions of the endocrine glands directly depend on the full-fledged work of the pituitary gland (consists of 2 parts), which occupies a dominant place in the endocrine system. This organ is located in the region of the skull (its sphenoid bone) and is attached to the brain from below. The pituitary gland regulates normal work thyroid gland, parathyroid gland, the entire reproductive system, adrenal glands.
The brain is divided into sections, one of which is the hypothalamus. It completely controls the work of the pituitary gland, as well as from its normal functioning depends on the nervous system. The hypothalamus captures and interprets all the signals of the work of the internal organs of the human body, based on this information, it regulates the work of the organs that produce hormones.
The human endocrine glands are produced by the anterior pituitary gland under the guidance of commands from the hypothalamus. The effect of hormones on the endocrine system is presented in a tabular format:
In addition to the substances mentioned above, the anterior pituitary gland secretes several other hormones, namely:
- Somatotropic (accelerates protein production inside the cell, affects the synthesis simple sugars, splitting of fat cells, ensures the full functioning of the body);
- Prolactin (synthesizes milk inside the milk channels, and also dulls the action of sex hormones during the lactation period).
Prolactin directly affects metabolic processes organism, growth and development of cells. Influences the instinctive behavior of a person in the field of protection, care of his offspring.
neurohypophysis
The neurohypophysis is the second part of the pituitary gland, which serves as a repository of certain biological substances produced by the hypothalamus. The endocrine glands of a person produce the hormones vasopressin, oxytocin, which accumulate in the neurohypophysis and after a while are released into the circulatory system.
Vasopressin directly affects the functioning of the kidneys, removing water from them, preventing dehydration. This hormone constricts blood vessels, stopping bleeding, increases blood pressure in the arteries and maintains the tone of smooth muscles surrounding the internal organs. Vasopressin affects human memory, controls the aggressive state.
The endocrine glands secrete the hormone oxytocin, which stimulates the bile bladder, intestinal and urinary systems. For the female body, oxytocin has a significant effect on the contraction of the uterine muscles, regulates the processes of fluid synthesis in the mammary glands, and its delivery for nutrition. baby after childbirth.
Thyroid and parathyroid gland
These organs belong to the endocrine glands. The thyroid gland is fixed with the trachea in its upper part using connective tissue. It consists of two lobes and an isthmus. Visually, the thyroid gland has the shape of an inverted butterfly, and weighs about 19 grams.
The endocrine system, with the help of the thyroid gland, produces thyroxine and triiodothyronine hormonal substances belonging to the thyroid group of hormones. They are involved in cellular nutrient and energy metabolism.
The main functions of the thyroid gland are:
- support of the set temperature indicators of the human body;
- maintaining the organs of the body during stress or physical exertion;
- transport of fluid into cells, exchange of nutrients, as well as active participation in the creation of a renewed cellular environment.
The parathyroid gland is located on the back of the thyroid gland in the form of small objects weighing approximately 5 grams. These processes can be either paired or single, which is not a pathology. The endocrine system, thanks to these processes, synthesizes hormonal substances - paratins, which balance the concentration of calcium in the blood environment of the body. Their action balances the hormone calcitonin secreted by the thyroid gland. He tries to lower the calcium content as opposed to paratins.
epiphysis
This pineal organ is located in the central part of the brain. Weighs only a quarter of a gram. The nervous system depends on its proper functioning. The epiphysis is attached to the eyes by means optic nerves and works depending on the external illumination of the space in front of the eyes. In the dark, it synthesizes melatonin, and in the light - serotonin.
Serotonin has a positive effect on good health, muscle activity, dulls pain, accelerates blood clotting in case of injuries. Melatonin is responsible for blood pressure, good sleep and immunity, is involved in puberty and maintaining sexual libido.
Another substance secreted by the pineal gland is adrenoglomerulotropin. Its significance in the work of the endocrine system is not yet fully understood.
Thymus
This organ (thymus) belongs to total number mixed glands. The main function of the thymus gland is the synthesis of thymosin, a hormonal substance involved in immune and growth processes. With the help of this hormone, the required amount of lymph and antibodies are maintained.
adrenal glands
These organs are located at the top of the kidneys. They are involved in the production of adrenaline and norepinephrine, which ensure the reaction of internal organs to stressful situation. Nervous system puts the body on alert in the event of dangerous situations.
The adrenal glands consist of a three-layered cortical substance that produces the following enzymes:
| Place of synthesis | Hormone name | Functions |
| beam region | Cortisol and corticosterone | Activates the metabolism of proteins and carbohydrates, participates in the synthesis of glycogen, glucose and providing the body with immunity |
| tangle region | Corticosterone, deoxycorticosterone and aldosterone | Participates in water and salt metabolism, regulating processes of blood pressure in the arteries and the total volume of the blood environment |
| mesh area | Testosterone, androstenedione, estradiol, dehydroepiandrosterone | Takes part in the synthesis of sex hormones |
Violation of the function of internal secretion, more precisely the adrenal glands, can lead to bronze disease and can even cause the formation malignant tumor. primary signs an unhealthy condition of the adrenal glands is a rash on skin age spots bronze hue, fatigue, as well as unstable work of the digestive system, drastic changes blood pressure.
Pancreas
Located behind the stomach. The pancreatic islets are a small part of this gland and are capable of producing:
- Secretion of insulin (transport functions of simple sugars);
- Glucagon secretion (glucose synthesis).
With the help of the pancreas, digestive juices are produced, exocrine function is performed.
Secretory organs of the reproductive system
The sex glands also belong to the endocrine system and consist of:
- Testicles and testicles (men) - synthesize androgenic hormones;
- Oocytes (women) - produce endogenous hormonal substances.
They ensure the normal functioning of the reproductive system, participate in: the formation of secondary sexual characteristics, determine the structure of bones, muscle skeleton, hair growth on the body, the level of fat, the shape of the larynx.
Sex hormones are of particular importance for general condition organism. They influence the processes of shaping, especially this can be seen by paying attention to castrated domestic animals.
The hormones of the reproductive system are actively involved in the synthesis of spermatozoa, eggs and excretion through the channels of the genital ducts in their accordance. Only the full functioning of the entire hormonal (endocrine) system is the key to a healthy and fulfilling life.
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