What Is It, Functions, Organs & Conditions

The endocrine system is a network of glands and organs located throughout the body. It’s similar to the nervous system in that it plays a vital role in controlling and regulating many of the body’s functions.

However, while the nervous system uses nerve impulses and neurotransmitters for communication, the endocrine system uses chemical messengers called hormones.

Keep reading to discover more about the endocrine system, what it does, and the hormones it produces.

The endocrine system is responsible for regulating a range of bodily functions through the release of hormones.

Hormones are secreted by the glands of the endocrine system, traveling through the bloodstream to various organs and tissues in the body. The hormones then tell these organs and tissues what to do or how to function.

Some examples of bodily functions that are controlled by the endocrine system include:

• metabolism
• growth and development
• sexual function and reproduction
• heart rate
• blood pressure
• appetite
• sleeping and waking cycles
• body temperature

What is a gland?

A gland is an organ that creates and releases substances that the body needs to function. There are two types of glands:

• endocrine glands, which release hormones directly into the bloodstream
• exocrine glands, like lymph nodes and sweat glands, which are not part of the endocrine system

The glands of the endocrine system are where hormones are produced, stored, and released. Each gland produces one or more hormones, which go on to target specific organs and tissues in the body.

The glands of the endocrine system include the:

• Hypothalamus. While some people don’t consider it a gland, the hypothalamus produces multiple hormones that control the pituitary gland. It’s also involved in regulating many functions, including sleep-wake cycles, body temperature, and appetite. It can also regulate the function of other endocrine glands.
• Pituitary. The pituitary gland is located below the hypothalamus. The hormones it produces affect growth and reproduction. They can also control the function of other endocrine glands.
• Pineal. This gland is found in the middle of your brain. It’s important for your sleep-wake cycles.
• Thyroid. The thyroid gland is located in the front part of your neck. It’s very important for metabolism.
• Parathyroid. Also located in the front of your neck, the parathyroid gland is important for maintaining control of calcium levels in your bones and blood.
• Thymus. Located in the upper torso, the thymus is active until puberty and produces hormones that are important for the development of a type of white blood cell called a T cell.
• Adrenal. One adrenal gland can be found on top of each kidney. These glands produce hormones that are important for regulating functions such as blood pressure, heart rate, and stress response.
• Pancreas. The pancreas is located in your abdomen behind your stomach. Its endocrine function involves controlling blood sugar levels.

Some endocrine glands also have non-endocrine functions. For example, the ovaries and testes produce hormones, but they also have the non-endocrine function of producing eggs and sperm, respectively.

Hormones are the chemicals the endocrine system uses to send messages to organs and tissue throughout the body. Once released into the bloodstream, hormones travel to their target organ or tissue, which has receptors that recognize and react to the hormone.

Below are some examples of hormones that are produced by the endocrine system.

Explore the interactive 3-D diagram below to learn more about the endocrine system.

Sometimes, hormone levels can be too high or too low. When this happens, it can have a number of effects on your health. The signs and symptoms depend on the hormone that’s out of balance.

Here’s a look at some conditions that can affect the endocrine system and alter your hormone levels.

Hyperthyroidism

Hyperthyroidism happens when your thyroid gland makes more thyroid hormone than necessary. This can be caused by a range of things, including autoimmune conditions.

Some common symptoms of hyperthyroidism include:

• fatigue
• nervousness
• weight loss
• diarrhea
• issues tolerating heat
• fast heart rate
• trouble sleeping

Treatment depends on how severe the condition is, as well as its underlying cause. Options include medications, radioiodine therapy, or surgery.

Graves‘ disease is an autoimmune disorder and a common form of hyperthyroidism. In people with Graves‘ disease, the immune system attacks the thyroid, which causes it to produce more thyroid hormone than usual.

Hypothyroidism

Hypothyroidism occurs when your thyroid doesn’t produce enough thyroid hormone. Similar to hyperthyroidism, it has many potential causes.

Some common symptoms of hypothyroidism include:

• fatigue
• weight gain
• constipation
• issues tolerating the cold
• dry skin and hair
• slow heart rate
• irregular periods
• fertility issues

Treatment for hypothyroidism involves supplementing your thyroid hormone with medication.

Cushing syndrome

Cushing syndrome happens due to high levels of the hormone cortisol.

Common symptoms of Cushing syndrome include:

• weight gain
• fatty deposits in the face, midsection, or shoulders
• stretch marks, particularly on the arms, thighs, and abdomen
• slow healing of cuts, scrapes, and insect bites
• thin skin that bruises easily
• irregular periods
• decreased sex drive and fertility in males

Treatment depends on the cause of the condition and can include medications, radiation therapy, or surgery.

Addison’s disease

Addison’s disease happens when your adrenal glands don’t produce enough cortisol or aldosterone. Some symptoms of Addison’s disease include:

• fatigue
• weight loss
• abdominal pain
• low blood sugar
• nausea or vomiting
• diarrhea
• irritability
• a craving for salt or salty foods
• irregular periods

Treatment for Addison’s disease involves taking medications that help replace the hormones your body isn’t producing enough of.

Diabetes

Diabetes refers to a condition in which your blood sugar levels aren’t regulated within a certain range.

People with diabetes have too much glucose in their blood (high blood sugar). There are two types of diabetes: type 1 diabetes and type 2 diabetes.

Some common symptoms of diabetes include:

• fatigue
• increased hunger or thirst
• frequent urge to urinate
• irritability
• frequent infections

Treatment for diabetes can include blood sugar monitoring, insulin therapy, and medications. Lifestyle changes, such as getting regular exercise and eating a balanced diet, can also help.

Polycystic ovary syndrome (PCOS)

This common condition is caused by unbalanced reproductive hormones in people with ovaries, which can create issues in the ovaries. Living with PCOS can mean that an egg may not be released every month, or may not develop as it should when it is released.

Some of the common symptoms of PCOS are:

• irregular periods
• fertility issues
• cysts that form on the ovaries
• acne
• hirsutism, which is an unusual amount of hair growth on the face or chin
• thinning hair
• weight gain
• skin tags

Treatment for PCOS focuses on easing the symptoms. Treatments include medications, like birth control and metformin, and lifestyle changes, such as focusing on nutrition and trying to reach a moderate weight if your doctor has recommended it.

Hypogonadism

A common condition, especially in older males and occasionally in females, hypogonadism is caused by a lowered production of the sex hormone testosterone. This can lead to lowered libido, as well as a variety of other symptoms, such as:

• erectile dysfunction in people with a penis
• reduced energy
• reduced muscle mass
• depressed mood
• increased irritability

Treatment for hypogonadism focuses on improved testosterone levels. Testosterone replacement therapy and lifestyle changes (such as working toward a moderate weight if your doctor has recommended it) are two popular methods.

Osteoporosis

Osteoporosis is an abnormal loss of bone mass and changes in bone tissue. It can be caused by a variety of issues, but two common causes are lowered estrogen levels in people with ovaries and lowered testosterone levels in people with testicles. These lowered hormone levels can be caused by age, as well as other diseases.

Osteoporosis doesn‘t always cause obvious symptoms. But some of the more common symptoms are bone fractures and injuries related to minor falls, lifting, and even coughing.

Treatment for osteoporosis focuses on slowing or stopping bone loss. Proper nutrition, exercise, and medications are three of the most common treatments.

Acromegaly

This rare disease is caused when the body makes too much growth hormone, which is mainly produced in the pituitary gland. Mostly diagnosed in middle-aged adults, it can cause organs, bones, cartilage, organs, and certain tissues to grow in size.

The common symptoms of acromegaly include:

• swollen nose
• swollen ears
• swollen hands and feet
• joint aches
• a deeper voice than usual
• an increase in sweating and body odor

Treatment for acromegaly includes medications, radiation therapy, and surgery.

The endocrine system is a complex collection of glands and organs that helps regulate various bodily functions. This is accomplished through the release of hormones, or chemical messengers, produced by the endocrine system.

What Is It, Functions, Organs & Conditions

The endocrine system is a network of glands and organs located throughout the body. It’s similar to the nervous system in that it plays a vital role in controlling and regulating many of the body’s functions.

However, while the nervous system uses nerve impulses and neurotransmitters for communication, the endocrine system uses chemical messengers called hormones.

Keep reading to discover more about the endocrine system, what it does, and the hormones it produces.

The endocrine system is responsible for regulating a range of bodily functions through the release of hormones.

Hormones are secreted by the glands of the endocrine system, traveling through the bloodstream to various organs and tissues in the body. The hormones then tell these organs and tissues what to do or how to function.

Some examples of bodily functions that are controlled by the endocrine system include:

• metabolism
• growth and development
• sexual function and reproduction
• heart rate
• blood pressure
• appetite
• sleeping and waking cycles
• body temperature

What is a gland?

A gland is an organ that creates and releases substances that the body needs to function. There are two types of glands:

• endocrine glands, which release hormones directly into the bloodstream
• exocrine glands, like lymph nodes and sweat glands, which are not part of the endocrine system

The glands of the endocrine system are where hormones are produced, stored, and released. Each gland produces one or more hormones, which go on to target specific organs and tissues in the body.

The glands of the endocrine system include the:

• Hypothalamus. While some people don’t consider it a gland, the hypothalamus produces multiple hormones that control the pituitary gland. It’s also involved in regulating many functions, including sleep-wake cycles, body temperature, and appetite. It can also regulate the function of other endocrine glands.
• Pituitary. The pituitary gland is located below the hypothalamus. The hormones it produces affect growth and reproduction. They can also control the function of other endocrine glands.
• Pineal. This gland is found in the middle of your brain. It’s important for your sleep-wake cycles.
• Thyroid. The thyroid gland is located in the front part of your neck. It’s very important for metabolism.
• Parathyroid. Also located in the front of your neck, the parathyroid gland is important for maintaining control of calcium levels in your bones and blood.
• Thymus. Located in the upper torso, the thymus is active until puberty and produces hormones that are important for the development of a type of white blood cell called a T cell.
• Adrenal. One adrenal gland can be found on top of each kidney. These glands produce hormones that are important for regulating functions such as blood pressure, heart rate, and stress response.
• Pancreas. The pancreas is located in your abdomen behind your stomach. Its endocrine function involves controlling blood sugar levels.

Some endocrine glands also have non-endocrine functions. For example, the ovaries and testes produce hormones, but they also have the non-endocrine function of producing eggs and sperm, respectively.

Hormones are the chemicals the endocrine system uses to send messages to organs and tissue throughout the body. Once released into the bloodstream, hormones travel to their target organ or tissue, which has receptors that recognize and react to the hormone.

Below are some examples of hormones that are produced by the endocrine system.

Explore the interactive 3-D diagram below to learn more about the endocrine system.

Sometimes, hormone levels can be too high or too low. When this happens, it can have a number of effects on your health. The signs and symptoms depend on the hormone that’s out of balance.

Here’s a look at some conditions that can affect the endocrine system and alter your hormone levels.

Hyperthyroidism

Hyperthyroidism happens when your thyroid gland makes more thyroid hormone than necessary. This can be caused by a range of things, including autoimmune conditions.

Some common symptoms of hyperthyroidism include:

• fatigue
• nervousness
• weight loss
• diarrhea
• issues tolerating heat
• fast heart rate
• trouble sleeping

Treatment depends on how severe the condition is, as well as its underlying cause. Options include medications, radioiodine therapy, or surgery.

Graves‘ disease is an autoimmune disorder and a common form of hyperthyroidism. In people with Graves‘ disease, the immune system attacks the thyroid, which causes it to produce more thyroid hormone than usual.

Hypothyroidism

Hypothyroidism occurs when your thyroid doesn’t produce enough thyroid hormone. Similar to hyperthyroidism, it has many potential causes.

Some common symptoms of hypothyroidism include:

• fatigue
• weight gain
• constipation
• issues tolerating the cold
• dry skin and hair
• slow heart rate
• irregular periods
• fertility issues

Treatment for hypothyroidism involves supplementing your thyroid hormone with medication.

Cushing syndrome

Cushing syndrome happens due to high levels of the hormone cortisol.

Common symptoms of Cushing syndrome include:

• weight gain
• fatty deposits in the face, midsection, or shoulders
• stretch marks, particularly on the arms, thighs, and abdomen
• slow healing of cuts, scrapes, and insect bites
• thin skin that bruises easily
• irregular periods
• decreased sex drive and fertility in males

Treatment depends on the cause of the condition and can include medications, radiation therapy, or surgery.

Addison’s disease

Addison’s disease happens when your adrenal glands don’t produce enough cortisol or aldosterone. Some symptoms of Addison’s disease include:

• fatigue
• weight loss
• abdominal pain
• low blood sugar
• nausea or vomiting
• diarrhea
• irritability
• a craving for salt or salty foods
• irregular periods

Treatment for Addison’s disease involves taking medications that help replace the hormones your body isn’t producing enough of.

Diabetes

Diabetes refers to a condition in which your blood sugar levels aren’t regulated within a certain range.

People with diabetes have too much glucose in their blood (high blood sugar). There are two types of diabetes: type 1 diabetes and type 2 diabetes.

Some common symptoms of diabetes include:

• fatigue
• increased hunger or thirst
• frequent urge to urinate
• irritability
• frequent infections

Treatment for diabetes can include blood sugar monitoring, insulin therapy, and medications. Lifestyle changes, such as getting regular exercise and eating a balanced diet, can also help.

Polycystic ovary syndrome (PCOS)

This common condition is caused by unbalanced reproductive hormones in people with ovaries, which can create issues in the ovaries. Living with PCOS can mean that an egg may not be released every month, or may not develop as it should when it is released.

Some of the common symptoms of PCOS are:

• irregular periods
• fertility issues
• cysts that form on the ovaries
• acne
• hirsutism, which is an unusual amount of hair growth on the face or chin
• thinning hair
• weight gain
• skin tags

Treatment for PCOS focuses on easing the symptoms. Treatments include medications, like birth control and metformin, and lifestyle changes, such as focusing on nutrition and trying to reach a moderate weight if your doctor has recommended it.

Hypogonadism

A common condition, especially in older males and occasionally in females, hypogonadism is caused by a lowered production of the sex hormone testosterone. This can lead to lowered libido, as well as a variety of other symptoms, such as:

• erectile dysfunction in people with a penis
• reduced energy
• reduced muscle mass
• depressed mood
• increased irritability

Treatment for hypogonadism focuses on improved testosterone levels. Testosterone replacement therapy and lifestyle changes (such as working toward a moderate weight if your doctor has recommended it) are two popular methods.

Osteoporosis

Osteoporosis is an abnormal loss of bone mass and changes in bone tissue. It can be caused by a variety of issues, but two common causes are lowered estrogen levels in people with ovaries and lowered testosterone levels in people with testicles. These lowered hormone levels can be caused by age, as well as other diseases.

Osteoporosis doesn‘t always cause obvious symptoms. But some of the more common symptoms are bone fractures and injuries related to minor falls, lifting, and even coughing.

Treatment for osteoporosis focuses on slowing or stopping bone loss. Proper nutrition, exercise, and medications are three of the most common treatments.

Acromegaly

This rare disease is caused when the body makes too much growth hormone, which is mainly produced in the pituitary gland. Mostly diagnosed in middle-aged adults, it can cause organs, bones, cartilage, organs, and certain tissues to grow in size.

The common symptoms of acromegaly include:

• swollen nose
• swollen ears
• swollen hands and feet
• joint aches
• a deeper voice than usual
• an increase in sweating and body odor

Treatment for acromegaly includes medications, radiation therapy, and surgery.

The endocrine system is a complex collection of glands and organs that helps regulate various bodily functions. This is accomplished through the release of hormones, or chemical messengers, produced by the endocrine system.

Functions of the endocrine glands in the human body.

Tests for hormones and their interpretation.

The human endocrine system consists of organs called endocrine glands, which regulate the work of the whole organism by releasing biologically active substances – hormones – into the circulatory system. These substances perform paramount functions in the body: they help maintain homeostasis, control growth and development, participate in metabolic processes, are responsible for responding to changes in environmental conditions, and regulate the reproductive system.

Endocrine glands include:

Thyroid. Produces hormones – thyroxine (T4), triiodothyronine (T3), calcitonin. These hormones are involved in metabolism, increasing its intensity, regulate growth processes in the body, increase the level of consumption of vital oxygen by organs and tissues.

Parathyroid glands. They produce parathyroid hormone that regulates the level of calcium in the body, which is necessary for the normal functioning of the motor apparatus and nervous system.

Thymus (thymus). This organ occupies a central place in the human immune system, not without reason the word “thymus” is translated from ancient Greek as “life force”. The thymus produces T-lymphocytes – immune cells that provide antiviral and antitumor protection of the body. It secretes a number of hormones into the blood: thymalin, thymosin, IGF-1, thymopoietin, which are responsible for the functional activity of the immune system.

Adrenals. They produce the so-called stress hormone – adrenaline, which is involved in the body’s response to external stressful situations. When a large amount of adrenaline is released into the blood, breathing quickens, the heart rate increases, blood vessels constrict, and the pupils dilate.

Pancreas. Is the main source of enzymes for the digestion of fats, proteins and carbohydrates. It produces the hormones insulin, which lowers the level of glucose in the blood, and glucagon, on the contrary, increases it.

Gonads. In women, the ovaries; in men, the testes. The hormones produced by these glands are responsible for reproductive function.

Pituitary and hypothalamus. Form the hypothalamic-pituitary system. The pituitary gland produces hormones that control almost the entire endocrine system. Among them, the most important is the growth hormone – somatotropin, which affects the growth of bones, cartilage and muscles.

Epiphysis (pineal body, or pineal gland). The organ performs important functions: it slows down growth hormones, inhibits the development of tumors, and affects sexual development. It produces antidiuretic hormone (ADH), which controls the water balance of the body, oxytocin, which is responsible for muscle contraction, and melatonin, a hormone that controls the sequence of sleep phases.

Based on the foregoing, we can follow the conclusion that the importance of the endocrine system cannot be overestimated – its activity extends to all organs of the body and all processes occurring in it. Therefore, all deviations from the norm in the operation of this system require immediate medical intervention.

Symptoms of hormonal imbalance

There are a lot of symptoms of malfunctioning of the endocrine glands, among them are:

• Irregular or absent menstruation in women;
• Miscarriage or infertility;
• Loss of sexual desire;
• Weight gain;
• Eruptions on the body, acne;
• Deterioration of hair and nails;
• Sleep disturbances, lethargy, increased fatigue;
• Emotional instability: tearfulness, irascibility, nervousness;
• The development of osteoporosis is a disease that leads to brittle bones.

It is worth noting that none of the above symptoms is a direct confirmation of the presence of a hormonal imbalance, but only a possible consequence. To make an accurate diagnosis, it is necessary to undergo a complete examination by an endocrinologist, which includes the method of functional diagnostics (ultrasound, MRI), as well as laboratory blood tests, which will be discussed below.

How is blood tested for hormones?

A blood test for hormones is the most indicative and informative method for detecting any pathologies in the work of the endocrine glands. However, it is important to consider that many factors influence the hormonal background: the time of day, the menstrual cycle in women, and medication. For this reason, the preparation for taking tests for a hormonal study must be taken with all seriousness. If this is neglected, then the result of the analysis may be incorrect and, at best, it will have to be retaken, and at worst, an incorrect diagnosis may be made on its basis and the wrong treatment may be prescribed, which can lead to irreparable consequences.

To prepare for donating blood for hormones, the following general rules must be observed:

• On the eve of the test, you should give up physical activity, try to avoid stressful situations, stop any physiotherapy procedures, exclude oral contraceptives, alcohol, fatty foods and products containing iodine. It is also recommended to postpone the ECG, ultrasound, x-ray examination for a while after the test.
• An important point is taking medications – it is necessary to notify the doctor who ordered the hormonal blood test about the fact of taking medications. He will decide whether to cancel or continue taking medications at the time of the test.
• An analysis for a hormonal study is given strictly on an empty stomach. Therefore, it is recommended to stop eating 12 hours before blood sampling.
• In the morning, before the test, it is forbidden to chew gum, drink tea and smoke.
• Just before donating blood, rest for 15-10 minutes.
• Women need to take into account their menstrual cycle, because. it is possible to examine the blood for some hormones only in certain periods of this cycle.
• To track the dynamics of the levels of certain hormones, a second analysis is required. It is rented at approximately the same time as the previous one, in compliance with all the above rules.

Blood sampling for analysis is carried out in the first half of the day in the morning. The biomaterial is taken from the cubital vein.

Explanation of tests

Thyroid hormones

Triiodothyronine , or T3 – gives a general assessment of the work of the thyroid gland. This hormone is determined both in free form (norm: from 2.6 to 5.7 pmol/l.), And in the serum state, (general form; norm: from 1.3 to 2.7 nmol/l). An increase in the indicator indicates the use of narcotic substances: methadone, heroin, amphetamine, HIV infection, renal failure, hyperthyroidism. The decrease was established with the use of androgens, danazol, dexamethasone, propranolol.

Thyroxine , or T4 – regulates energy metabolism in the body. Norm: 10.8 – 22.0 pmol / l. A low level is observed with hyperthyroidism, hemolysis. Elevated levels – when taking oral contraceptives, methodone, heroin, estrogen.

Thyroglobulin , or Tg – is prescribed for suspected malignant neoplasms. Norm: < 55 ng / ml.

Antibodies to thyroglobulin – are prescribed for suspected autoimmune thyroid diseases. Norm: 0 – 18 U / ml.

Microsomal antibodies are the most accurate indicator of the presence of autoimmune diseases. A deviation from the norm < 5.6 U / ml is proof of the aggression of the immune system to its own body.

Thyroxine-binding globulin , or TSH, is responsible for the transport of the hormones T3 and T4. Norm: from 16.8 to 22.5 mcg / ml. An increased indicator may indicate pregnancy, a lower one – with cirrhosis of the liver.

Adrenal hormones

Cortisol – regulates carbohydrate metabolism. Norm: from 230 to 750 nm / l. A low rate may be the result of chronic adrenal insufficiency, and a high one may indicate oncology or adenoma.

Aldosterone – responsible for the water-salt balance. Norms: in a horizontal position 17. 6-230.2 pg / ml; in a vertical position 25.2-392 pg / ml. Elevated levels of the hormone in the blood usually indicate an adrenal tumor.

Norepinephrine and epinephrine – normalize heart rate, blood pressure, form glucose levels. Norms: from 1.92 to 2.46 nm / l for adrenaline, from 0.62 to 3.23 nm / l for norepinephrine. An increase in indicators indicates kidney disease, Itsenko-Cushing’s syndrome, emotional and physical workload of the body, a decrease indicates pathology of the hypothalamus.

Sex hormones

Estradiol – is responsible for the production of germ cells and the proper development of pregnancy. The norm in the first phase of the menstrual cycle (follicular phase) is from 200 to 285 pm/l, the norm in the corpus luteum phase (luteal phase) is from 440 to 575 pi/l, during menopause from 50 to 133 pm/l. A lower indicator may indicate a tumor in the ovaries, an increased indicator – with their insufficient functioning.

Testosterone is the main male hormone. Responsible for the formation of secondary sexual characteristics, stimulates the growth of muscle mass and bones. Norms: for men – 2 -10 ng / ml, for women – 0.2 – 1 ng / l.

Progesterone – ensures the proper development of the genital organs in women. The norm in the first phase of the menstrual cycle (follicular phase) is from 1 to 2.2 nm / l, the norm in the corpus luteum phase (luteal phase) is from 23 to 30 nm / l, during menopause from 1 to 1.8 nm / l. An increase in the indicator is observed with tumors of the adrenal cortex, a decrease – with ovarian sclerosis.

Pituitary hormones

Thyroid stimulating hormone , or TSH, stimulates the production of the main thyroid hormones, so deviations from the reference values ​​​​indicate thyroid dysfunction. Norm: 0.4-4.0 honey / l.

Somatotropic hormone , or STH – a hormone of the anterior pituitary gland, is responsible for stimulating the mouth of bones, muscle mass and other organs of the human body. Norm: < 10.0 ng / ml. Exceeding the value of the established norm indicates gigantism, acromegaly.

Adrenocorticotropic hormone , or ACTH – stimulates the synthesis of hormones in the adrenal cortex. Norm: < 46 pg / ml. Deviations from the norm are observed in Itsenko-Cushing's syndrome, Addison's disease, as well as in other disorders of the adrenal glands.

Prolactin is a hormone responsible for the growth of the mammary glands in women and the functioning of the prostate in men. The norm for the stronger sex is 100 – 265 mcg / l, for the fair sex – from 130 to 540 skg / l during the childbearing period.

Follicle-stimulating hormone , FSH – stimulates the growth of follicles in women, is responsible for the functioning of the seminiferous tubules in men. The norm in women: in the first phase of the menstrual cycle (follicular phase) from 1.37 – 9.90 IU / l, in the corpus luteum phase (luteal phase) from 1. 09 – 9.20 IU / ml, during menopause from 29.5 to 55 IU / l, during ovulation from 2.7 to 6.7 IU / ml. The norm for men: 0.95 – 11.95 mU / ml.

Luteinizing hormone , or LH – stimulates the production of testosterone in men, progesterone in women. Normal values ​​for men: from 1.14 to 8.75 mU / ml. Norm for women: in the follicular phase from 1.68 to 15.00 mU / ml, in the ovulatory phase from 21.90 – 56.60 mU / ml, in the luteal phase: 0.61 – 16.30 mU / ml, in postmenopausal women from 14.20 – 52.30 mU / ml. Deviations from normal values ​​in both sexes indicate dysfunction of the gonads.

Endocrine system. Humoral regulation – what is it, definition and answer

All glands of the body are usually divided into glands:

• Internal secretion = endocrine (releasing hormone into the blood): thyroid gland, pituitary gland, adrenal glands, pineal gland, thymus.

• External (excrete into the body cavity or beyond): sweat, sebaceous, salivary, mammary glands.

• Mixed secretion (hormone + secretion into the blood + into the body cavity or beyond): pancreas, gonads.

All endocrine glands secrete hormones.

Hormones are biologically active substances that are produced in specialized cells of the endocrine glands, enter the blood and have a regulatory effect on metabolism and physiological functions.

Pituitary gland (interbrain)

Pituitary gland is the most important gland that regulates many functions of the body, some of its hormones control the activity of other endocrine glands, for example, pituitary hormone thyrotropin stimulates the production and activation of thyroxine, a thyroid hormone.

Other hormones also have a tremendous effect on the body, for example, somatotropin (growth hormone) regulates the growth of the body at a young age, with a lack of it, dwarfism will develop, and with an excess, gigantism.

Epiphysis (midbrain)

This endocrine gland plays the role of a “biological clock”. Receiving information about the time of day from the visual analyzer, the pineal gland controls the production of melatonin . This hormone is responsible for the regulation of circadian rhythms, that is, for the desire to sleep and stay awake.

Pineal hormones also affect the functions of the pituitary gland (hormone serotonin ), thyroid gland, adrenal glands, control puberty and inhibit the function of the gonads in childhood.

Thymus

In the chest behind the sternum is located the thymus, or the thymus. It consists of two lobes resembling the horns of a fork. Its value changes with age – in childhood, the thymus is much larger than in adulthood.

Thymus is the central organ of the immune system.

Immune cells are formed and trained in it, harmful agents are “remembered”, the formation of immunity depends on it.

Thyroid and parathyroid glands

Thyroid gland is the largest endocrine gland of internal secretion. It consists of two lobes that hug the upper part of the trachea like a tie. On the back surface are 4 parathyroid (parathyroid) glands.

Thyroxine – the most important thyroid hormone, it affects the whole body and regulates metabolism. Iodine is required for its synthesis.

With hypofunction (deficiency) of thyroxin, adults develop myxedema , which is expressed in swelling, decreased metabolism and excitability of the nervous system, and obesity. Children will develop dwarfism with a violation of body proportions and cretinism.

With hyperfunction (excess) of thyroxin, increased excitability of the nervous system, increased metabolism, weight loss, the appearance of goiter – an increase in the size of the thyroid gland.

Another thyroid hormone calcitonin is responsible for controlling the amount of calcium in the blood. Together with parathyroid hormones, it maintains the level of calcium in the blood within the normal range.

Adrenal glands

Adrenal glands are paired glands that are located at the tops of the kidneys. They consist of inner (brain) and outer (cortical) layers.

The hormone of the inner layer adrenaline accelerates the work of the heart, constricts blood vessels, slows down digestion, increases the amount of glucose in the blood.

Hormones of the outer layer corticoids regulate the metabolism of mineral and organic substances, the release of sex hormones, the activity of allergic and inflammatory reactions.

Pancreas

Pancreas – large gland mixed secretion. It secretes digestive enzymes into the duodenal cavity, and the hormone insulin into the blood (endocrine function).

Insulin regulates blood glucose, glycogen synthesis from excess glucose, fat deposition.

With hypofunction , a disease such as diabetes mellitus develops, which is accompanied by an increase in blood sugar, the appearance of sugar in the urine, increased blood pressure and viscosity, and many other side effects.

In case of hyperfunction of the pancreas, a lack of glucose is formed in the blood, the brain may lack nutrition and a person may fall into a coma.

Sex glands

Sex glands, or gonads – testes (testicles) in men and ovaries in women are among the glands with mixed secretion.

Gonads are referred to glands of mixed secretion .

Sex hormones promote embryonic differentiation, in the subsequent development of the genital organs and the appearance of secondary sexual characteristics, determine puberty and human behavior.

Male sex hormones (androgens)

All sex hormones are synthesized from one precursor – cholesterol. The most important of the androgens is testosterone.

Female sex hormones

These hormones are produced in the female sex glands – the ovaries, during pregnancy – in the placenta. Men also produce female sex hormones, just in smaller quantities. It occurs in the cells of the testicles.

Ovarian follicles synthesize estrogens ( stimulate the development of primary and secondary female sexual characteristics, the development and growth of the mammary glands, affect the development of the bone skeleton, the emotional and mental state of women; during pregnancy, estrogens promote the growth of uterine muscle tissue, effective uteroplacental circulation, together with progesterone and prolactin – the development of mammary glands).

The corpus luteum of the ovary produces progesterone (prepares the uterus for the attachment of a fertilized egg and ensures the normal course of pregnancy; participates in the regulation of the menstrual cycle).