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Glands of the human endocrine system: The Endocrine System and Glands of the Human Body: Function and Disorders


Anatomy of the Endocrine System

The endocrine system is a complex network of glands and organs. It uses hormones to control and coordinate your body’s metabolism, energy level, reproduction, growth and development, and response to injury, stress, and mood. The following are integral parts of the endocrine system:

  • Hypothalamus. The hypothalamus is located at the base of the brain, near the optic chiasm where the optic nerves behind each eye cross and meet. The hypothalamus secretes hormones that stimulate or suppress the release of hormones in the pituitary gland, in addition to controlling water balance, sleep, temperature, appetite, and blood pressure.

  • Pineal body. The pineal body is located below the corpus callosum, in the middle of the brain. It produces the hormone melatonin, which helps the body know when it’s time to sleep.

  • Pituitary. The pituitary gland is located below the brain. Usually no larger than a pea, the gland controls many functions of the other endocrine glands.

  • Thyroid and parathyroid. The thyroid gland and parathyroid glands are located in front of the neck, below the larynx (voice box). The thyroid plays an important role in the body’s metabolism. The parathyroid glands play an important role in the regulation of the body’s calcium balance.

  • Thymus. The thymus is located in the upper part of the chest and produces white blood cells that fight infections and destroy abnormal cells.

  • Adrenal gland. An adrenal gland is located on top of each kidney. Like many glands, the adrenal glands work hand-in-hand with the hypothalamus and pituitary gland. The adrenal glands make and release corticosteroid hormones and epinephrine that maintain blood pressure and regulate metabolism.

  • Pancreas. The pancreas is located across the back of the abdomen, behind the stomach. The pancreas plays a role in digestion, as well as hormone production. Hormones produced by the pancreas include insulin and glucagon, which regulate levels of blood sugar.

  • Ovary. A woman’s ovaries are located on both sides of the uterus, below the opening of the fallopian tubes (tubes that extend from the uterus to the ovaries). In addition to containing the egg cells necessary for reproduction, the ovaries also produce estrogen and progesterone.

  • Testis. A man’s testes are located in a pouch that hangs suspended outside the male body. The testes produce testosterone and sperm.

  • What is it, Functions & Organs

    What is the endocrine system?

    Your endocrine system is made up of several organs called glands. The glands, located all over your body, create and secrete (release) hormones.

    Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.

    What does the endocrine system do and how does it work?

    Hormones deliver their messages by locking into the cells they are targeting so they can relay the message. Your endocrine system continuously monitors the amounts of hormones in your blood.

    The pituitary gland senses when hormone levels rise, and tells other glands to stop producing and releasing hormones. When hormone levels dip below a certain point, the pituitary gland can instruct other glands to produce and release more. This process, called homeostasis, works similarly to the thermostat in your house.

    Hormones affect nearly every process in your body, including:

    • Metabolism (the way you break down food and get energy from nutrients).
    • Growth and development.
    • Emotions and mood.
    • Fertility and sexual function.
    • Sleep.
    • Blood pressure.

    Sometimes glands produce too much or not enough of a hormone. This imbalance can cause health problems, such as weight gain, high blood pressure and changes in sleep, mood and behavior. Many things can affect how your body creates and releases hormones. Illness, stress and certain medications can cause a hormone imbalance.

    What are the parts of the endocrine system?

    The endocrine system is made up of organs called glands. Glands produce and release different hormones that target specific things in the body. You have glands all over your body, including in your neck, brain and reproductive organs. Some glands are tiny, about the size of a grain of rice or a pea. The largest gland is the pancreas, which is about 6 inches long.

    The main glands that produce hormones include:

    • Hypothalamus: This gland is located in your brain and controls your endocrine system. It uses information from your nervous system to determine when to tell other glands, including the pituitary gland, to produce hormones. The hypothalamus controls many processes in your body, including your mood, hunger and thirst, sleep patterns and sexual function.
    • Pituitary: This little gland is only about the size of a pea, but it has a big job. It makes hormones that controls several other gland such as the thyroid gland, adrenal glands, ovaries and testicles. The pituitary gland is in charge of many different functions, including how your body grows. It’s located at the base of your brain.
    • Thyroid: Your thyroid is a butterfly-shaped gland in the front of your neck. It’s responsible for your metabolism (how the body uses energy).
    • Parathyroid: These four tiny glands are no larger than a grain of rice. They control the level of calcium in your body. For your heart, kidneys, bones and nervous system to work, you need the right amount of calcium.
    • Adrenal: You have two adrenal glands, one on top of each kidney. They control your metabolism, blood pressure, sexual development and response to stress.
    • Pineal: This gland manages your sleep cycle by releasing melatonin, a hormone that causes you to feel sleepy.
    • Pancreas: Your pancreas is part of your endocrine system, and it plays a significant role in your digestive system too. It makes a hormone called insulin that controls the level of sugar in your blood.
    • Ovaries: In women, the ovaries release sex hormones called estrogen, progesterone and testosterone. Women have two ovaries in their lower abdomen, one on either side.
    • Testes: In men, the testes (testicles) make sperm and release the hormone testosterone. This hormone affects sperm production, muscle strength and sex drive.

    What conditions and disorders affect the endocrine system?

    Dozens of conditions can cause issues in the endocrine system. These conditions can lead to health problems all over the body. Some of the most common disorders are:

    • Diabetes: This endocrine disorder affects the way your body uses the energy from the food you eat. Diabetes develops when the pancreas doesn’t make enough of a hormone called insulin, or insulin doesn’t work as it should.
    • Thyroid disorders: Several conditions can affect the function of the thyroid gland. Hypothyroidism happens when the thyroid doesn’t produce enough hormones. Hyperthyroidism occurs when it creates too many hormones.
    • Hypogonadism (low testosterone): In men, hypogonadism can cause erectile dysfunction. It can also cause memory and concentration problems, changes in muscle strength and low sex drive. It happens when the testes do not produce enough of the sex hormone testosterone.
    • Polycystic ovary syndrome (PCOS): A hormonal imbalance causes women with PCOS to have irregular periods, abnormal hair growth, excess acne and weight gain. It can lead to diabetes, increased risk of metabolic syndrome and infertility.
    • Osteoporosis: When a woman’s ovaries don’t produce enough estrogen, bones become brittle and weak. Although it is more common in women, men sometimes have osteoporosis when testosterone levels get too low. People with an overactive parathyroid gland (hyperparathyroidism) may also have weak bones.

    Chemicals called endocrine disrupters can also affect the endocrine system. These chemicals appear everywhere — in pesticides, plastics, cosmetics and even our food and water. Endocrine disrupters cause a wide range of problems throughout the body by changing how hormones send messages.

    How common are these conditions?

    • Diabetes: This condition is widespread. Almost 10% of people in the United States have diabetes and 27% have prediabetes.
    • Thyroid disorders: About 20 million Americans have thyroid disease. Women are about five times more likely than men to develop the condition.
    • Hypogonadism: About 40% of men over 45 have low testosterone. Levels of this sex hormone naturally drop as men age. Other factors, such as a man’s diet, weight and other health problems also affect testosterone levels.
    • PCOS: This common condition affects about 5% to 10% of adult women in the U.S. It is a leading cause of infertility.
    • Osteoporosis: More than half of adults over age 50 have osteoporosis. It is more likely to occur in women than in men.

    How can I keep my endocrine system healthy?

    Your endocrine system needs the same things the rest of your body needs to stay healthy. You should exercise, eat right and see your healthcare provider regularly.

    If you have a family history of diabetes, thyroid disorders or PCOS, talk to your provider. Managing these conditions can help you avoid a hormone imbalance that can lead to health problems.

    When should I call my doctor?

    Some symptoms can point to a serious health condition, such as diabetes. Call your provider if you have:

    • The urge to urinate (pee) a lot.
    • Extreme thirst, even after you’ve had plenty of water.
    • Nausea or stomach pain that doesn’t go away.
    • Sudden weight loss or unexplained weight gain.
    • Severe exhaustion or weakness.
    • Problems with sweating too much.
    • Sudden episodes of rapid heart hearts or elevated blood pressure
    • Developmental or growth delays.

    A Look at the Endocrine System

    Feeling hormonal?” Or, “It’s just the hormones!” We all complain about hormones without really knowing where they come from or what they do. Turns out, these chemical messengers don’t deserve as much flack as they’re getting. In fact, we should be worshipping the glands where these chemical messengers secrete from. Vital for survival, hormones provide the relay system every cell needs to send information and instructions through the body. Where do these miraculous messengers come from? The endocrine system: a network of glands throughout the body that regulates some pretty important functions like body temperature, metabolism, growth, and sexual development.

    Image from Human Anatomy Atlas. 

    Like the digestive system, the endocrine system is made up of primary and secondary organs (we can’t all come in first). The primary organs include the hypothalamus and pancreas along with the pituitary, thyroid, pineal, and parathyroid and adrenal glands, which all release regulatory hormones, while the secondaries include the gonads, kidneys, heart, and thymus.

    Together, all the endocrine glands and their hormones regulate things like metabolism and the sleep cycle, as well as growth and development. You don’t have to tell this system twice that there’s no place like homeostasis.

    But what is the endocrine system, exactly, and how does this complex, crucial network affect the body? Read on to find out!

    Let’s start with hormones, and then move on to their homes. When endocrine glands and organs secrete hormones into the bloodstream, those chemical messengers go everywhere. Our hormones are picky, though. They’ll only bind to specific target cells with receptors just for them. That binding triggers changes in the behavior of the cells. If a type of hormone binds to enough cells, it will adjust the corresponding functions of organs and body processes.  

    And where does it start? The brain (typical). Two hormone command centers in the brain—namely, the hypothalamus and the pituitary gland—are the dynamic duo in charge of this entire operation. After receiving signals from other brain regions, the hypothalamus translates them into the endocrine language: hormones, which then travel to the pituitary. This signal sets in motion signals to either inhibit or release certain hormones, some of which will act directly, affecting skeletal and muscular development and processes such as birth and nurturing, or indirectly, serving as commands to subordinate endocrine glands.


    Image from Human Anatomy Atlas.

    Since the hypothalamus is where it all begins, why not start here with it? Nestled below the thalamus and above the pituitary gland, the hypothalamus is a collection of specialized cells that serves as the central relay system between the nervous and endocrine systems. By secreting hormones that stimulate or inhibit production of other hormones in the anterior pituitary, this gland plays a crucial role in the release of hormones such as luteinizing hormone/follicle-stimulating hormone (LH/FSH—crucial for sex cell production), growth hormone–releasing hormone (GHRH—pretty self-explanatory), thyrotropin-releasing hormone (TRH) to regulate thyroid-stimulating hormone release, and corticotropin-releasing hormone (CRH) to regulate the adrenocorticotropin release vital to the production of cortisol (stress response hormone).

    As you might imagine, in the instance of hypothalamic dysfunction or lack of function due to surgery, brain injury, tumors, etc. , some of the aforementioned signaling processes may not occur. This can result in hormonal deficiencies with varying symptoms and severities. Luckily, treatment is often possible through hormone replacement therapies.


    Image from Human Anatomy Atlas.

    Whoever said bigger is better wasn’t too familiar with the pituitary. No bigger than a peanut, the pituitary gland is located at the base of the brain inferior to the hypothalamus, and is often considered the most important part of the endocrine system. It secretes endorphins (you know, the chemical root of happiness), as well as controlling several other endocrine glands, and regulating the ovulation and menstrual cycle. That is one busy gland.

    Divided into two parts, the pituitary’s anterior lobe regulates the activity of the thyroid, adrenals, and reproductive glands by producing hormones that regulate bone and tissue growth in addition to playing a role in absorption of nutrients and minerals. This lobe is also responsible for the secretion of prolactin, a hormone vital to activating milk production in new mothers; thyrotropin, which stimulates the thyroid gland to produce thyroid hormones vital to metabolic regulation; and corticotropin, which is vital in stimulating the adrenal gland and the “fight-or-flight” response (don’t you adrenaline junkies fret, we’ll get back to this).

    Not to be outdone by its neighbor, the posterior lobe releases antidiuretic hormone, which helps maintain the body’s water balance in addition to producing oxytocin, which triggers the labor contractions in the uterus.

    Given its governing role in growth and development (and pretty much everything else), you can imagine that a malfunctioning pituitary isn’t good news for anyone, and you’d be right. An overactive pituitary or a tumor located on the pituitary can result in excessive production of all aforementioned hormonal signals. Excessive production of growth hormones, for example, will result in excessive growth of certain body parts, especially in young children. Treatment is usually medication-based or surgical in the case of a tumor. On the other hand, an underactive pituitary, which fails to produce adequate amounts of growth hormone, can stunt a child’s development, most noticeably height.


    Image from Human Anatomy Atlas.

    Encasing the trachea below the larynx sits the thyroid gland. Vital to growth and development, the thyroid hormone produced here regulates metabolism and nervous system activity, in addition to producing cells that secrete the hormone calcitonin, which aids in the regulation of blood calcium levels. While this gland might lack the laundry list of structures and functions of some others (we can’t all be the pituitary), it’s equally vital for the decisive role it plays in physical development by stimulating the growth and development of bone as well as brain and nervous system structures. 

    For all those fifty-somethings complaining about their sluggish metabolism, hyperthyroidism might seem like a dream. It’s not. In hyperthyroidism, the levels of thyroid hormones in the blood are excessively high; sufferers experience weight loss, nervousness, tremors, excessive sweating, increased heart rate and blood pressure, as well as protruding eyes and swelling in the neck from the enlarged gland. Inversely, in hypothyroidism, the levels of thyroid hormones are abnormally low, usually resulting in fatigue, slow heart rate, dry skin, weight gain, constipation, and, in children, slowing of growth and delays in puberty. In both cases treatment usually involves medications or surgery.


    Image from Human Anatomy Atlas.

    On the posterior surface of the thyroid sit the parathyroids. Tiny by comparison to the thyroid, these four glands secrete parathyroid hormone (PTH), which stimulates bones to release calcium into the blood when blood calcium levels are low. PTH also causes the kidneys to conserve calcium by reducing secretion into the urine in the instance of decreased blood calcium levels. Together, calcitonin and PTH act in complementary ways to maintain blood calcium homeostasis.

    As you might imagine, too much PTH release (hyperparathyroidism), often caused by a tumor on the parathyroid gland, fosters a corrosive hormonal breakdown of bone, resulting in pain, fractures, and osteoporosis, in addition to heart palpitations and vascular blockages caused by excess calcium in the blood (released by the bones as they break down). Inversely, too little PTH release (hypoparathyroidism), which is often caused by accidental damage to the parathyroid during surgery or trauma to the head or neck, leads to abnormally low blood and bone calcium levels and an increase in blood phosphorus levels. While rare and often irreversible, side effects of these conditions are often treatable with supplements to manually manage bodily calcium availability and absorption.

    Adrenal Glands

    Image from Human Anatomy Atlas.

    Pyramid-shaped organs perched atop each kidney, the adrenal glands consist of two structures: an outer adrenal cortex and an inner adrenal medulla. The adrenal cortex is a network of fine connective tissues that secretes a range of steroid hormones. These include glucocorticoids, such as cortisol, to manage protein and glucose levels; mineralocorticoids, which adjust levels of water and salt; and gonadocorticoids (aka androgens and estrogens). Last but certainly not least, the adrenal medulla produces epinephrine and norepinephrine (NE), chemicals vital to initiating the increased breathing and heart rate as the first step in the “fight-or-flight” bodily response to stress (told you we’d be back). These chemicals will also give your muscles a burst of energy, enabling you to either face that petrifying spider or run for dear life to find someone less arachnophobic to do so for you.

    In small doses, the adrenal glands are crucial for arachnid confrontations as well as subsequent life-threatening encounters that you might wish to flee, yet overfunction of the adrenal glands doesn’t make you run faster, alas. Excess glucocorticoid hormone production can cause Cushing syndrome. Characterized by obesity, growth failure, muscle weakness, easy bruising of the skin, acne, high blood pressure, and psychological changes, the disease often results from a tumor or the use of synthetic corticosteroid drugs such as prednisone to treat autoimmune diseases such as lupus. 

    With decreased function of the adrenal cortex comes, no, not running slower, exactly, though you’re not far off. Underproduction of adrenal corticosteroid hormones often causes weakness, fatigue, abdominal pain, nausea, dehydration, and skin changes, and it’s typically treated, like many other hormonal deficits, by administering replacement hormones.

    Pineal Gland

    Image from Human Anatomy Atlas.

    If you’ve ever traveled to northern Scandinavia or the Arctic Circle (typical summer destinations for the beach bums among us) and had your exotic polar holiday ruined by a lack of sleep, don’t blame your travel agent (or maybe do). It’s actually your pineal gland’s fault. Or maybe payback for all those all-nighters in college, who knows. This pinecone-shaped gland located at the posterior center of the brain activates with the absence of light at night to secrete the hormone melatonin, which in turn regulates our sleep patterns in both daily (circadian) and seasonal rhythms. In the morning (or at 1 a.m. north of a certain longitude in June), when light hits the eye, photoreceptors in the retina send signals to the pineal gland, which then decreases melatonin production, aka your body’s way of saying “Wakey wakey!”  


    Images from Human Anatomy Atlas.

    But before these glands get up on their high horses, it must be noted that other organs also secrete hormones. Despite their categorization as secondary organs of the endocrine system, their purpose is by no means subpar; in fact, these organs are working double time. A key facet of the digestive system, for instance, is the excretion of pancreatic juices into the small intestine via the pancreatic duct. The pancreas belongs to this special group of overachievers for its tiny cell clusters called pancreatic islets (or islets of Langerhans) that release hormones into the bloodstream. Despite making up less than 2% of pancreatic tissue, these islets regulate blood glucose levels (blood sugar) by signaling alpha cells in the islets to release glucagon when blood sugar is low, causing the liver to break down glycogen and release glucose into the blood, and beta cells when blood sugar is high to release insulin and glucose re-uptake. 

    If you need proof of this supposedly “secondary” organ’s primary importance within the endocrine system and beyond, just ask any diabetic. Broken down into types 1 and 2, diabetes is thought to be the result (in the instance of type 1) of an autoimmune disorder in which specific immune system cells and antibodies attack and destroy the insulin-producing cells of the pancreas. Rude. Symptoms include excessive thirst, hunger, urination (peeing), and weight loss.

    The long-term complications of failing to treat type 1 diabetes with blood glucose monitoring and regular injections of insulin include kidney malfunction, nerve damage, blindness, and early coronary heart disease and stroke. 

    Unlike type 1, in which the body fails to produce normal amounts of insulin, in type 2 diabetes the body develops insulin resistance due largely to environmental conditions. Despite their differing causes, the symptoms and possible lethal complications of type 2 diabetes are largely the same as those of type 1.


    Whether you’re stressed, pissed, thrilled, starving, or sprinting from danger, you likely owe how you feel (and how you deal with those feelings) largely to the endocrine system. So next time you feel like sneaking an extra donut or throwing a nasty tantrum, don’t be so quick to let yourself (or let your significant other) blame the hormones; they’re vital to how we enjoy those circular vessels of sugar and fat in the first place, and how we calm down post-conniption. And what’s a world without enjoyable donuts anyway?

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    Additional Sources:

    1. “Hormones and the Endocrine System.” Hormones and the Endocrine System | Johns Hopkins Medicine Health Library. N.p., n.d. Web. 16 June 2017.

    2. “Endocrine System.” KidsHealth. Ed. Steven Dowshen. The Nemours Foundation, July 2015. Web. 16 June 2017.

    Endocrine System

    Endocrine System

    Although we rarely think about them, the glands of the endocrine system and the hormones they release influence almost every cell, organ, and function of our bodies. The endocrine system is instrumental in regulating mood, growth and development, tissue function, and metabolism, as well as sexual function and reproductive processes.

    In general, the endocrine system is in charge of body processes that happen slowly, such as cell growth. Faster processes like breathing and body movement are controlled by the nervous system. But even though the nervous system and endocrine system are separate systems, they often work together to help the body function properly.

    About the Endocrine System

    The foundations of the endocrine system are the hormones and glands. As the body’s chemical messengers, hormones transfer information and instructions from one set of cells to another. Although many different hormones circulate throughout the bloodstream, each one affects only the cells that are genetically programmed to receive and respond to its message. Hormone levels can be influenced by factors such as stress, infection, and changes in the balance of fluid and minerals in blood.

    A gland is a group of cells that produces and secretes, or gives off, chemicals. A gland selects and removes materials from the blood, processes them, and secretes the finished chemical product for use somewhere in the body.

    Some types of glands release their secretions in specific areas. For instance, exocrine glands, such as the sweat and salivary glands, release secretions in the skin or inside of the mouth. Endocrine glands, on the other hand, release more than 20 major hormones directly into the bloodstream where they can be transported to cells in other parts of the body.

    Parts of the Endocrine System

    The major glands that make up the human endocrine system are the hypothalamus, pituitary, thyroid, parathyroids, adrenals, pineal body, and the reproductive glands, which include the ovaries and testes. The pancreas is also part of this hormone-secreting system, even though it is also associated with the digestive system because it also produces and secretes digestive enzymes.

    Although the endocrine glands are the body’s main hormone producers, some non-endocrine organs — such as the brain, heart, lungs, kidneys, liver, thymus, skin, and placenta — also produce and release hormones.

    The Hypothalamus

    The hypothalamus, a collection of specialized cells that is located in the lower central part of the brain, is the primary link between the endocrine and nervous systems. Nerve cells in the hypothalamus control the pituitary gland by producing chemicals that either stimulate or suppress hormone secretions from the pituitary.

    Although it is no bigger than a pea, the pituitary gland, located at the base of the brain just beneath the hypothalamus, is considered the most important part of the endocrine system. It’s often called the “master gland” because it makes hormones that control several other endocrine glands.

    The production and secretion of pituitary hormones can be influenced by factors such as emotions and seasonal changes. To accomplish this, the hypothalamus relays information sensed by the brain (such as environmental temperature, light exposure patterns, and feelings) to the pituitary.

    The Pituitary Gland

    The tiny pituitary gland is divided into two parts: the anterior lobe and the posterior lobe. The anterior lobe regulates the activity of the thyroid, adrenals, and reproductive glands. Among the hormones it produces are:

    • growth hormone, which stimulates the growth of bone and other body tissues and plays a role in the body’s handling of nutrients and minerals
    • prolactin, which activates milk production in women who are breastfeeding
    • thyrotropin, which stimulates the thyroid gland to produce thyroid hormones
    • corticotropin, which stimulates the adrenal gland to produce certain hormones

    The pituitary also secretes endorphins, chemicals that act on the nervous system to reduce sensitivity to pain. In addition, the pituitary secretes hormones that signal the ovaries and testes to make sex hormones. The pituitary gland also controls ovulation and the menstrual cycle in women.

    The posterior lobe of the pituitary releases antidiuretic hormone, which helps control body water balance through its effect on the kidneys and urine output; and oxytocin, which triggers the contractions of the uterus that occur during labor.

    The Thyroid and Parathyroids

    The thyroid, located in the front part of the lower neck, is shaped like a bow tie or butterfly and produces the thyroid hormones thyroxine and triiodothyronine. These hormones control the rate at which cells burn fuels from food to produce energy. As the level of thyroid hormones increases in the bloodstream, so does the speed at which chemical reactions occur in the body.

    Thyroid hormones also play a key role in bone growth and the development of the brain and nervous system in children. The production and release of thyroid hormones is controlled by thyrotropin, which is secreted by the pituitary gland.

    Attached to the thyroid are four tiny glands that function together called the parathyroids. They release parathyroid hormone, which regulates the level of calcium in the blood with the help of calcitonin, which is produced in the thyroid.

    The Adrenal Glands

    The body has two triangular adrenal glands, one on top of each kidney. The adrenal glands have two parts, each of which produces a set of hormones and has a different function. The outer part, the adrenal cortex, produces hormones called corticosteroids that influence or regulate salt and water balance in the body, the body’s response to stress, metabolism, the immune system, and sexual development and function.

    The inner part, the adrenal medulla, produces catecholamines, such as epinephrine. Also called adrenaline, epinephrine increases blood pressure and heart rate when the body experiences stress. (Epinephrine injections are often used to counteract a severe allergic reaction.)

    The Pineal Gland and Gonads

    The pineal body, also called the pineal gland, is located in the middle of the brain. It secretes melatonin, a hormone that may help regulate the wake-sleep cycle.

    The gonads are the main source of sex hormones. In males, they are located in the scrotum. Male gonads, or testes, secrete hormones called androgens, the most important of which is testosterone. These hormones regulate body changes associated with sexual development, including enlargement of the penis, the growth spurt that occurs during puberty, and the appearance of other male secondary sex characteristics such as deepening of the voice, growth of facial and pubic hair, and the increase in muscle growth and strength. Working with hormones from the pituitary gland, testosterone also supports the production of sperm by the testes.

    The female gonads, the ovaries, are located in the pelvis. They produce eggs and secrete the female hormones estrogen and progesterone. Estrogen is involved in the development of female sexual features such as breast growth, the accumulation of body fat around the hips and thighs, and the growth spurt that occurs during puberty. Both estrogen and progesterone are also involved in pregnancy and the regulation of the menstrual cycle.

    The Pancreas

    The pancreas produces (in addition to others) two important hormones, insulin and glucagon. They work together to maintain a steady level of glucose, or sugar, in the blood and to keep the body supplied with fuel to produce and maintain stores of energy.

    What the Endocrine System Does

    Once a hormone is secreted, it travels from the endocrine gland through the bloodstream to target cells designed to receive its message. Along the way to the target cells, special proteins bind to some of the hormones. The special proteins act as carriers that control the amount of hormone that is available to interact with and affect the target cells.

    Also, the target cells have receptors that latch onto only specific hormones, and each hormone has its own receptor, so that each hormone will communicate only with specific target cells that possess receptors for that hormone. When the hormone reaches its target cell, it locks onto the cell’s specific receptors and these hormone-receptor combinations transmit chemical instructions to the inner workings of the cell.

    When hormone levels reach a certain normal or necessary amount, further secretion is controlled by important body mechanisms to maintain that level of hormone in the blood. This regulation of hormone secretion may involve the hormone itself or another substance in the blood related to the hormone.

    For example, if the thyroid gland has secreted adequate amounts of thyroid hormones into the blood, the pituitary gland senses the normal levels of thyroid hormone in the bloodstream and adjusts its release of thyrotropin, the pituitary hormone that stimulates the thyroid gland to produce thyroid hormones.

    Another example is parathyroid hormone, which increases the level of calcium in the blood. When the blood calcium level rises, the parathyroid glands sense the change and decrease their secretion of parathyroid hormone. This turnoff process is called a negative feedback system.

    Problems With the Endocrine System

    Too much or too little of any hormone can be harmful to the body. For example, if the pituitary gland produces too much growth hormone, a child may grow excessively tall. If it produces too little, a child may be abnormally short.

    Controlling the production of or replacing specific hormones can treat many endocrine disorders in children and adolescents, some of which include:

    Adrenal insufficiency. This condition is characterized by decreased function of the adrenal cortex and the consequent underproduction of adrenal corticosteroid hormones. The symptoms of adrenal insufficiency may include weakness, fatigue, abdominal pain, nausea, dehydration, and skin changes. Doctors treat adrenal insufficiency by giving replacement corticosteroid hormones.

    Cushing syndrome. Excessive amounts of glucocorticoid hormones in the body can lead to Cushing syndrome. In children, it most often results when a child takes large doses of synthetic corticosteroid drugs (such as prednisone) to treat autoimmune diseases such as lupus. If the condition is due to a tumor in the pituitary gland that produces excessive amounts of corticotropin and stimulates the adrenals to overproduce corticosteroids, it’s known as Cushing disease.

    Symptoms may take years to develop and include obesity, growth failure, muscle weakness, easy bruising of the skin, acne, high blood pressure, and psychological changes. Depending on the specific cause, doctors may treat this condition with surgery, radiation therapy, chemotherapy, or drugs that block the production of hormones.

    Type 1 diabetes. When the pancreas fails to produce enough insulin, type 1 diabetes (previously known as juvenile diabetes) occurs. Symptoms include excessive thirst, hunger, urination, and weight loss. In children and teens, the condition is usually an autoimmune disorder in which specific immune system cells and antibodies produced by the immune system attack and destroy the cells of the pancreas that produce insulin.

    Type 1 diabetes can cause long-term complications, including kidney problems, nerve damage, blindness, and early coronary heart disease and stroke. To control their blood sugar levels and reduce the risk of developing diabetes complications, kids need regular injections of insulin.

    Type 2 diabetes. Unlike type 1 diabetes, in which the body can’t produce normal amounts of insulin, in type 2 diabetes the body is unable to respond to insulin normally. Children and teens with this condition tend to be overweight, and it is believed that excess body fat plays a role in the insulin resistance that characterizes the disease. In fact, the rising prevalence of this type of diabetes in kids has paralleled the dramatically increasing rates of obesity among kids in recent years.

    The symptoms and possible complications of type 2 diabetes are basically the same as those of type 1. Some kids and teens can control their blood sugar level with dietary changes, exercise, and oral medications, but many will need to take insulin injections like those with type 1 diabetes.

    Growth hormone problems. Too much growth hormone in children who are still growing will make their bones and other body parts grow excessively, resulting in gigantism. This rare condition is usually caused by a pituitary tumor and can be treated by removing the tumor.

    In contrast, when the pituitary gland fails to produce adequate amounts of growth hormone, a child’s growth in height is impaired. Hypoglycemia (low blood sugar) may also occur in kids with growth hormone deficiency, particularly in infants and young children with the condition.

    Hyperthyroidism. Hyperthyroidism is a condition in which the levels of thyroid hormones in the blood are excessively high. Symptoms may include weight loss, nervousness, tremors, excessive sweating, increased heart rate and blood pressure, protruding eyes, and a swelling in the neck from an enlarged thyroid gland (goiter).

    In kids this is usually caused by Graves’ disease, an autoimmune disorder in which specific antibodies produced by the immune system stimulate the thyroid gland to become overactive. The disease may be controlled with medications or by removal or destruction of the thyroid gland through surgery or radiation treatments.

    Hypothyroidism. Hypothyroidism is when the levels of thyroid hormones in the blood are abnormally low. Thyroid hormone deficiency slows body processes and may lead to fatigue, a slow heart rate, dry skin, weight gain, constipation, and, in kids, slowing of growth and delayed puberty.

    Hashimoto’s thyroiditis, which results from an autoimmune process that damages the thyroid and blocks thyroid hormone production, is the most common cause of hypothyroidism in kids. Infants can also be born with an absent or underdeveloped thyroid gland, resulting in hypothyroidism. It can be treated with oral thyroid hormone replacement.

    Precocious puberty. Body changes associated with puberty may occur at an abnormally young age in some kids if the pituitary hormones that stimulate the gonads to produce sex hormones rise prematurely. An injectable medication is available that can suppress the secretion of these pituitary hormones (known as gonadotropins) and arrest the progression of sexual development in most of these children.

    Reviewed by: Steven Dowshen, MD
    Date reviewed: March 2012

    Hormonal (endocrine) system – Better Health Channel

    Endocrine glands make chemicals called hormones and pass them straight into the bloodstream. Hormones can be thought of as chemical messages.

    From the blood stream, the hormones communicate with the body by heading towards their target cell to bring about a particular change or effect to that cell. The hormone can also create changes in the cells of surrounding tissues (paracrine effect). The endocrine system works with the nervous system and the immune system to help the body cope with different events and stresses.

    This branch of medicine – relating to the study of the endocrine system – is called endocrinology and is practiced by endocrinologists. The field is rapidly expanding due to understanding of the cellular pathways that hormones stimulate and the discovery of new hormones and their actions.

    Exocrine glands

    An exocrine gland, unlike an endocrine gland, is a gland that secretes substances (electrolytes, proteins or enzymes) straight to a target site via ducts or tube. Some examples include:

    • Salivary glands
    • Sweat glands
    • Sebaceous glands
    • The pancreas.

    The pancreas is both an endocrine and exocrine organ. It releases certain enzymes to aid in digestion delivered to the gut via the pancreatic duct. The endocrine pancreas also releases hormones such as insulin and glucagon, which are hormones predominantly related to glucose metabolism, into the blood stream.

    Functions of the endocrine system

    Some of the roles of the endocrine system include:

    • Growth
    • Repair
    • Sexual reproduction
    • Digestion
    • Homeostasis (constant internal balance).

    How hormones work

    A hormone will only act on a part of the body if it ‘fits’. A hormone can be thought of as a key, and its target site (such as an organ) has specially shaped locks on the cell walls. If the hormone fits the cell wall, then it will work.

    The hormones can set off a cascade of other signaling pathways in the cell to cause an immediate effect (for instance, insulin signaling leads to a rapid uptake of glucose into muscle cells) or a more delayed effect (glucocorticoids bind to DNA elements in a cell to switch on the production of certain proteins, which takes a while to produce).

    The endocrine system is a tightly regulated system that keeps the hormones and their effects at just the right level. One way this is achieved is through ‘feedback loops’. The release of hormones is regulated by other hormones, proteins or neuronal signals.

    The released hormone then has its effect on other organs. This effect on the organ feeds back to the original signal to control any further hormone release. The pituitary gland is well known for its feedback loops.

    Endocrine glands and organs

    The main glands and organs of the endocrine system include:

    • Pituitary gland – is inside the brain. It oversees the other glands and keeps hormone levels in check. It can bring about a change in hormone production somewhere else in the system by releasing its own ‘stimulating’ hormones. The pituitary gland is also connected to the nervous system through part of the brain called the hypothalamus. The hormones released by the pituitary gland are gonadotropins (LH and FSH), growth hormone (GH), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), prolactin, antidiuretic hormone and oxytocin.
    • Thyroid gland – sits in the neck at the front of the windpipe. It releases thyroid hormone (T4 and T3) which is required for metabolism and body homeostasis. It is controlled by TSH which is produced by the pituitary gland through a feed-back loop.
    • Parathyroid gland – there are usually four parathyroid glands which lie alongside the thyroid gland. The parathyroid gland is involved in calcium, phosphate and vitamin D regulation.
    • Adrenal glands – there are two adrenal glands which sit on top of each kidney. They make a number of different hormones. The outside part of the gland (adrenal cortex) makes cortisol, aldosterone and sex hormones. The centre of the adrenal gland (adrenal medulla) makes adrenaline. Adrenaline is an example of a hormone that is under the control of the nervous system.
    • Pancreas – an organ of digestion which is inside the abdomen. It makes insulin, which controls the amount of sugar in the bloodstream. It also makes other hormones such as glucagon and somatostatin.
    • Ovaries – are inside the female pelvis. They make female sex hormones like oestrogen.
    • Testes – they hang in the male scrotal sack. They make male sex hormones like testosterone.

    Other lesser known endocrine organs include:

    • Adipose tissue (fat tissue) – is recognised to be metabolically important. It releases hormones such as leptin, which affect appetite, and is also a site of oestrogen production. Insulin also acts on adipose tissue.
    • Kidneys – produce erythropoietin (EPO) which stimulates red blood cell production, produce renin which is needed for blood pressure regulation and produce the active form of Vitamin D (1–25 dihydroxy vitamin D3)
    • Gut – an increasing number of hormones in the gut are being researched and being understood to effect metabolism and appetite. Included are glucagon-like peptide 1 (GLP–1), ghrelin which stimulates appetite, and somatostatin.

    Problems of the endocrine system

    Numerous problems can occur in the endocrine system. These can be considered as excessive or deficient hormone production. Endocrine organs are also prone to tumours (adenomas) which can over produce hormones. Some problems of the endocrine system include:

    • Diabetes – too much sugar in the blood caused by problems with insulin production. This includes type 1 diabetes (deficiency of insulin) and type 2 diabetes (initially excessive, then deficiency, of insulin).
    • Menstruation abnormalities – irregular menstruation or lack of menstruation. Some causes of this include polycystic ovarian syndrome (PCOS), pituitary adenoma or primary ovarian failure (POF).
    • Thyroid problems – when the gland is overactive (hyperthyroidism) or underactive (hypothyroidism). Thyroid nodules are common but thyroid cancers are rare.
    • Parathyroid problems – an enlargement or one of more of the parathyroid glands can lead to high calcium levels in the blood (hypercalcemia).
    • Pituitary adenomas – these are tumours of the pituitary gland that can make too much of a certain hormone or cause deficiencies of hormones. These tumours can be small (microadenomas) or large (macroadenomas).
    • Neuro-endocrine tumours – these are rare to tumours of certain endocrine glands (usually the adrenal gland, pancreas or small bowel). These can include too much adrenaline released by the adrenal gland (pheochromocytoma), or too much hormone 5–HIAA from a carcinoid tumour which causes diarrhoea and flushing.

    Where to get help

    • Australian Pituitary Foundation Tel. 1300 331 807
    • Thyroid Australia Tel. (03) 9888 2588
    • Diabetes Australia Tel. 13 RISK (13 7475)
    • Unicorn Foundation (for neuro-endocrine disorders) Tel. 1300 CURE NETS (2873 6387)
    • Andrology Australia Tel. 1300 303 878
    • Australian Menopause Society Tel. (07) 4642 1603
    • Jean Hailes for Women’s Health Tel. 1800 JEAN HAILES (532 642)

    Things to remember

    • Endocrine glands secrete hormones straight into the bloodstream.
    • Hormones help to control many body functions, such as growth, repair and reproduction.
    • The endocrine system involves many organ systems and hormones, many of which are still being investigated and understood.

    Endocrine Glands – Definition, Examples, Function


    Endocrine glands are tissues or organs that excrete chemical substances (hormones) directly into the blood. Common endocrine glands are the hypothalamus, pineal, and adrenal glands. Endocrine glands secrete hormones directly into the bloodstream or into the intercellular space, allowing the hormones to reach their target.


    Endocrine system glands are spaced throughout the entire body. They release a wide number of hormones which control the metabolism and function of other cells. Exocrine glands, by comparison, secrete substances inside and outside of the body using ducts. These two methods of transport mark the difference between exocrine and endocrine glands.

    While in the bloodstream, the hormones are able to travel through the body’s circulatory system to reach distant targets. Hormones, in turn, will carry out varied functions in the body depending on the receptors they bind and the quantity of the hormone that is present. These changes will reflect the balance of secretion and excretion of hormones in the body. Their duration will depend on the hormone’s inherent half-life and activity levels.

    Endocrine Glands Diagram

    As you can see in the image above, men and women share all of the same endocrine glands, besides the reproductive organs. While reproductive organs have the primary function of creating and releasing gametes, they also release a number of hormones which affect the body in different ways.

    Examples of Endocrine Glands

    Pineal Gland

    The pineal gland is a small gland located within the brain that serves as a great example of endocrine glands in general. The pineal gland is activated by neurons connected to your eyes. When these nerves are activated by light, the pineal gland is repressed. When nighttime comes, and the light reaching your eyes decreases, the pineal gland becomes activated.

    The pineal gland secretes melatonin, a hormone which activates our sleep cycle. By releasing this hormone when it gets dark, the pineal gland is helping your body coordinate for sleeping. This includes changing your respiratory rate, brain patterns, and even digestive patterns.

    Thyroid Gland

    The thyroid gland is found in your throat, just below the jaw. This gland secretes a number of hormones that act on your metabolism. Thyroid hormones can increase the rate of your cellular metabolism, or decrease it. These activities are in part directed by another endocrine gland, the pituitary, which signals to the thyroid which hormones to release. In turn, your metabolism is regulated. In fact, a nonfunctioning thyroid gland often leads to drastic weight gain or loss, depending on the malfunction.

    Function of Endocrine Glands

    Releasing Hormones

    The endocrine system derives its power from coordinating the interactions that take place between the hormones that are released by this network of glands. Endocrine glands themselves will inherently be able to make, secrete, and store hormones for future use. This ability to store hormones for later release is useful for modulating responses to certain stimuli. Depending on our developmental needs at whichever stage in life we are in, our endocrine system will ensure that a proper hormonal balance is in place so that we release more or less of certain hormone based on these needs. Many factors can compromise this balance, however, resulting in endocrine disease.

    One such instance is when too much or too little hormone is released from a given endocrine gland. Another problematic scenario is if an afflicted patient’s blood supply is not strong enough to carry the hormones the distance they need to be carried to reach their target organs. Furthermore, once the hormones reach their target site, the tissue must have an adequate number of hormone receptors to maintain this intricate balance.

    Responding to the Nervous System

    The actual release of hormones by endocrine glands is tempered by the nervous system. Hormone release will be directly tied to the body’s response to certain neural or hormonal stimuli. Hormones come in various forms; some may present as fatty steroids or long-chained amino acids. These substances will travel through our bloodstream to reach specific tissues or organs.

    The endocrine system will regulate our metabolic processes, our appetite, our growth, and even our sleeping patterns. Our endocrine glands will essentially help regulate our body’s energy distribution in order to wire all of these varied processes. Many tissues in our bodies have the ability to release chemical substances into our blood, but we will discuss the most major endocrine glands in more detail.

    List of Endocrine Glands

    Endocrine system

    The figure depicts the major endocrine glands of the human body.

    Within the Brain and Neck

    Among the most important endocrine glands in the human body is the hypothalamus. In spite of its small size, this part of the brain releases crucial chemicals that influence the body’s internal homeostasis as well as the pituitary gland. Its hormones include oxytocin and growth hormone, among many others.

    The pituitary gland, in turn, is another endocrine tissue that releases hormones related to growth, mental development, and sexual reproduction. Moving on to the pineal gland in the brain, the pineal body will create and release various hormones, including melatonin, which regulates our sleep and waking cycles and eventual sexual maturation. The thyroid is an endocrine gland in the neck that releases thyroid hormones that help maintain our body’s metabolic and energetic processes. The parathyroid gland, on the other hand, lies behind the thyroid gland and secretes chemicals that allow for normal bone development.

    Within the Body

    The thymus has much more important roles in immune health during our childhood (via T cell production), as it is eventually phased out by fat in post-pubescent children. The pancreas is another endocrine gland that releases insulin in the body, which importantly allows for sugar in the blood to be metabolized.

    Moving southward to the kidneys, the adrenal glands that lie above each will secrete adrenaline hormone during strenuous fight or flight situations. This modulation will likewise influence the way our bodies use energy.

    Lastly, our sex organs are a major type of endocrine gland. Ovaries in women will create estrogen and progesterone derivatives that help with our sexual development and will aid in the release of eggs for future fertilization. Thus, all of these glands orchestrate large processes that keep our species alive and thriving. Hence, the evolutionary importance of having endocrine tissue!

    Major Endocrine Glands:

    • Hypothalamus
    • Thyroid
    • Parathyroid
    • Pituitary gland
    • Adrenal glands
    • Pineal gland
    • Pancreas



    Endocrine Glands | Boundless Anatomy and Physiology

    Overview of Endocrine Glands

    Endocrine glands are glands that have no duct and release their secretions directly into the intercellular fluid or into the blood.

    Learning Objectives

    Differentiate among the types of endocrine glands (pituitary [posterior pituitary, anterior pituitary], thyroid, parathyroid, adrenal, and pancreas) in the endocrine system

    Key Takeaways

    Key Points
    • The main endocrine glands are the pituitary (anterior and posterior lobes), thyroid, parathyroid, adrenal (cortex and medulla), pancreas, and gonads.
    • The parathyroid glands are four masses of tissue, two embedded posteriorly in each lateral mass of the thyroid gland.
    • The pancreas lies along the lower curvature of the stomach, close to where it meets the first region of the small intestine, the duodenum.
    Key Terms
    • adrenal gland: This gland is responsible for releasing hormones in response to stress through the synthesis of corticosteroids, such as cortisol and catecholamines (epinephrine (adrenaline) and norepinephrine), as well as the production of androgens.
    • thyroid: One of the largest endocrine glands, it is responsible for the secretion of thyroxine which controls how quickly the body uses energy, makes proteins, and is sensitive to other hormones.

    Endocrine glands are ductless and release their secretions directly into the intercellular fluid or into the blood. A collection of endocrine glands makes up the endocrine system: the pituitary (anterior and posterior lobes), thyroid, parathyroid, adrenal (cortex and medulla), pancreas and gonads.

    Endocrine glands in the human head and neck: The endocrine system is the system of glands, each of which secretes different types of hormones directly into the bloodstream (some of which are transported along nerve tracts) to regulate the body.

    Pituitary Gland

    The hypothalamus makes up the lower region of the diencephalons and lies just above the brain stem. The pituitary gland (hypophysis) is found in the inferior part of the brain, attached to the bottom of the hypothalamus by a slender stalk called the infundibulum.

    The pituitary gland consists of two major regions, the anterior pituitary gland (adenohypophysis) and the posterior pituitary gland (neurohypophysis). The hypothalamus also controls the glandular secretion of the pituitary gland.

    Posterior Pituitary Gland

    Communication between the hypothalamus and the posterior pituitary occurs through neurosecretory cells that span the short distance between them. Hormones produced by the cell bodies of the neurosecretory cells are packaged in vesicles and transported through the axon and stored in the axon terminals that lie in the posterior pituitary.

    When the neurosecretory cells are stimulated, the action potential generated triggers the release of the stored hormones from the axon terminals to a capillary network within the posterior pituitary. Two hormones—oxytocin and antidiuretic hormone (ADH)—are produced and released this way.

    Anterior Pituitary Gland

    The anterior pituitary is involved in sending hormones that control all other hormones of the body. Its lobe is derived from oral ectoderm and is composed of glandular epithelium.

    Communication between the hypothalamus and the anterior pituitary occurs through hormones (releasing hormones and inhibiting hormones) that are produced by the hypothalamus and delivered to the anterior pituitary via a portal network of capillaries. The releasing and inhibiting hormones are produced by specialized neurons of the hypothalamus called neurosecretory cells.

    These hormones are released into a capillary network that supplies the anterior pituitary. The hormones then diffuse from this secondary plexus into the anterior pituitary, where they initiate the production of specific hormones by the anterior pituitary.

    Thyroid Gland

    This is one of the largest endocrine glands in the body. It is positioned on the neck just below the larynx and has two lobes, one on either side of the trachea.

    It is involved in the production of the hormones T3 (triiodothyronine) and T4 (thyroxine). These hormones increase the metabolic activity of the body‘s cells.

    The thyroid also produces and releases the hormone calcitonin (thyrocalcitonin) that contributes to the regulation of blood calcium levels. Thyrocalcitonin or calcitonin decreases the concentration of calcium in the blood, where most of it is stored in the bones.


    There are four parathyroid glands, all located on the thyroid gland. One of its most important functions is to regulate the body’s calcium and phosphorus levels.

    All four glands also secrete parathyroid hormone, or PTH, which causes calcium to be released from the bones back into the extracellular fluid. PTH is released directly into the bloodstream and travels to its target cells, which are often quite far away and found in bone, kidneys, and the gastrointestinal system.

    Calcitonin, a hormone produced by the thyroid gland that also regulates ECF calcium levels, serves to counteract the calcium-producing effects of PTH.

    Adrenal Glands

    Adrenal glands: These are responsible for releasing hormones in response to stress through the synthesis of corticosteroids such as cortisol, and catecholamines such as epinephrine (adrenaline) and norepinephrine.

    The adrenal glands are a pair of ductless glands located above the kidneys. Through hormonal secretions, they regulate many essential bodily functions including biochemical balances that influence athletic training and general stress response.

    The glucocorticoids include corticosterone, cortisone, and hydrocortisone or cortisol. These hormones serve to stimulate the conversion of amino acids into carbohydrates, a process known as gluconeogenesis, and the formation of glycogen by the liver. They also stimulate the formation of reserve glycogen in the tissues, such as in the muscles.


    The pancreas is a very important organ in the digestive and the circulatory systems that helps to maintain our blood sugar levels. It is considered to be part of the gastrointestinal system since it produces digestive enzymes. These are released into the small intestine to aid in reducing food particles to basic elements that can be absorbed by the intestine and used by the body.

    It has another, very different function in that it forms insulin, glucagon, and other hormones that are sent into the bloodstream to regulate blood sugar levels and other activities throughout the body.

    Human endocrine system – BU “Second City Hospital”, Cheboksary

    The endocrine system is understood as a set of endocrine glands that produce special substances – hormones, characterized by high biological activity (ensuring the body’s vital processes: growth, development, reproduction, adaptation, behavior).

    The most important for the human body are the pituitary gland, hypothalamus, thyroid and parathyroid glands, adrenal glands, sex glands and pancreas.There are also many other glands, but their structure and action are not fully understood.

    The central link of the endocrine system is the hypothalamus and pituitary gland. The hypothalamus, in response to nerve impulses, has a stimulating or inhibitory effect on the anterior lobe of the pituitary gland. Through the pituitary hormones, the hypothalamus regulates the function of the peripheral endocrine glands.

    Peripheral link of the endocrine system – adrenal glands, thyroid gland, parathyroid glands, testes, ovaries, islets of Langerhans (pancreas).

    The main functions of the endocrine glands.

    The hypothalamus is one of the brain regions. The main function of the hypothalamus, located at the base of the human skull, is to stimulate and control the work of all other organs of the endocrine and other body systems. It synthesizes hormones – vasopressin (takes part in the regulation of blood pressure, urination) and oxytocin (regulation of the activity of the muscles of the uterus), pituitary hormones (liberins and statins).

    Pituitary gland is considered one of the main endocrine glands in the human body. It is located in a special depression of the sphenoid bone of the cerebral skull. The main hormones of the pituitary gland: somatotropic (growth hormone), thyroid-stimulating, luteinizing, adrenocorticotropic, lactogenic (prolactin). Growth and reproduction depend on the normal functioning of the pituitary gland; basic, carbohydrate, mineral, fat and protein metabolism.

    The thyroid gland is located on the anterior surface of the neck.The hormones produced by the thyroid gland (thyroxine and triiodothyronine) provide growth, mental and physical development, and regulate the rate of metabolic processes.

    Parathyroid gland produces parathyroid hormone (parathyroid hormone), which is involved in the regulation of calcium and phosphorus metabolism in the body.

    Disruption of the pancreas and provokes the occurrence of such a common disease as diabetes. It produces glucagon and insulin, which are responsible for the metabolism and absorption of carbohydrates.

    The adrenal glands are two small glands located in the adrenal region. The basis of the adrenal gland is the medulla, which produces such important hormones as adrenaline and norepinephrine. They affect the state of the blood vessels, and norepinephrine narrows the vessels of all sections, with the exception of the brain, and adrenaline narrows part of the vessels, and partly expands. Adrenaline intensifies and speeds up heartbeats, while norepinephrine, on the contrary, can lower them.The adrenal cortex produces three types of corticosteroid hormones (aldosterone, cortisol, androgens) that affect the metabolism of carbohydrates, electrolytes and gonads.

    Sex glands are responsible for human reproduction. In the male gonads (testicles), the male sex hormone testosterone is produced, and in the female (ovaries) – estrogen and progesterone, which control all the changes that occur in the uterus during the menstrual cycle and pregnancy.

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

    Pathology of the endocrine system is expressed by diseases and pathological conditions, which are based on hyperfunction, hypofunction or dysfunction of the endocrine glands.

    Among the most common endocrine diseases and pathological conditions, diabetes mellitus and insipidus, diffuse toxic goiter (thyrotoxicosis), hypothyroidism, adrenal insufficiency, dysfunctions of the gonads and others should be noted.

    Functions of the endocrine glands in the human body.Tests for hormones and their decoding

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

    Parathyroid glands. Produce parathyroid hormone, which regulates the level of calcium in the body, which is necessary for the normal functioning of the locomotor system and the nervous system.

    Thymus (thymus). This organ is central to the human immune system, it is not for nothing that 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 releases a number of hormones into the bloodstream: thymalin, thymosin, IGF-1, thymopoietin, which are responsible for the functional activity of the immune system.

    Adrenal glands. 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, heart rate increases, blood vessels narrow, pupils dilate.

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

    Sex glands. In women – ovaries, in men – testes. The hormones produced by these glands are responsible for reproductive function.

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

    Epiphysis (pineal gland, 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 body’s water balance, 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 significance 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 attention.

    Symptoms of hormonal disruption

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

    • Irregular or absent menstruation in women;
    • Miscarriage or infertility;
    • Loss of sex drive;
    • Increase in body weight;
    • Rash 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 fragility of bones.

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

    How do you donate blood for hormones?

    Blood test for hormones is the most indicative and informative method of detecting any pathologies in the work of the endocrine glands.However, it is important to take into account that many factors affect the hormonal background: time of day, menstrual cycle in women, medication intake. For this reason, the preparation for the delivery of tests for hormonal research should be taken very seriously. 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, on its basis, an incorrect diagnosis may be made and the wrong treatment prescribed, which can lead to irreparable consequences.

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

    • On the eve of delivery, you should give up physical exertion, try to avoid stressful situations, stop any physiotherapy procedures, exclude the use of 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 analysis.
    • An important point is taking medications – it is necessary to notify the doctor who prescribed the hormonal blood test about the fact of taking medications. He will decide on the cancellation or further taking medications at the time of the test.
    • The analysis for hormonal research is taken strictly on an empty stomach. Therefore, it is recommended to stop eating 12 hours before blood sampling.
    • Do not chew gum, drink tea or smoke in the morning before testing.
    • Immediately before donating blood, you should rest for 15-10 minutes.
    • Women need to consider their menstrual cycle because it is possible to test blood for some hormones only in certain periods of this cycle.
    • To trace the dynamics of indicators of the level of certain hormones, a repeated analysis is required. He surrenders at about the same time as the previous one, subject to all of the above rules.

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

    Explanation of analyzes

    Thyroid hormones

    Triiodothyronine , or T3 – gives a general assessment 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 drugs: methadone, heroin, amphetamine, HIV infection, renal failure, hyperthyroidism.A decrease was found with the use of androgens, danazol, dexamethasone, propranolol.

    Thyroxin , or T4 – regulates energy metabolism in the body. Norm: 10.8 – 22.0 pmol / l. A low level is observed with hyperthyroidism, hemolysis. The increased level – when taking oral contraceptives, methodon, heroin, estrogens.

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

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

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

    Thyroxine-binding globulin , or TSH – is responsible for the transport of hormones T3 and T4. Norm: from 16.8 to 22.5 μg / 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 indicator may be the result of chronic adrenal insufficiency, and a high indicator may indicate oncology or adenoma.

    Aldosterone – responsible for the water-salt balance. Norms: in a horizontal position 17.6-230.2 pg / ml; in an upright position 25.2-392 pg / ml. An elevated level of the hormone in the blood usually indicates an adrenal tumor.

    Norepinephrine and adrenaline – normalize heart rate, blood pressure, and form glucose levels. Norms: from 1.92 to 2.46 nm / l for epinephrine, 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 – the 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, with menopause from 50 to 133 pm / l.A decreased indicator may indicate a tumor in the ovaries, an increased one – 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 correct development of the genitals in women. The norm in the first phase of the menstrual cycle (follicular phase) from 1 to 2.2 nm / l, the norm in the corpus luteum phase (luteal phase) from 23 to 30 nm / l, with 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 basic thyroid hormones, therefore deviations from the reference values ​​indicate thyroid dysfunction. Norm: 0.4-4.0 mU / l.

    Growth hormone , or STH – the 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. Excess of the value from 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 work 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 phase of the corpus luteum (luteal phase) from 1.09 – 9.20 IU / ml, with menopause from 29, 5 to 55 mU / l, with ovulation from 2.7 to 6.7 mU / ml. The norm in 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: 1.14 to 8.75 mU / ml. The norm for women: in the follicular phase from 1.68 to 15.00 mU / ml, in the ovulatory phase from 21.90 to 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

    The endocrine system regulates the functions of internal organs.This regulation is carried out by hormones secreted by endocrine cells directly into the blood or carried to neighboring cells through the cell membrane. Endocrinology studies all of these processes.

    The endocrine system is distinguished into glandular and diffuse. Glandular is when the endocrine glands are “scattered” throughout the body. Diffuse is already endocrine cells, which are also “scattered” throughout the body. Endocrine cells “divide” with the body hormones – aglandular peptides.

    Of course, the functions of the endocrine system are vitally important to humans. It participates in the chemical regulation of organs, systems and the body as a whole.

    It participates (along with the immune and nervous system) in the growth and development of the body, in sexual differentiation, controls reproductive function and energy conservation.

    Hormones produced by the endocrine system , , along with the nervous system, play an important role in the psychoemotional state of a person.

    What are these hormones? Hormones – couriers, entering the bloodstream, deliver chemicals to cells throughout the body.As already mentioned, hormones are produced in the endocrine glands and are proteins, steroids or protein derivatives.

    As it became known, hormones are also produced by organs – heart, liver, brain.

    Today we are familiar with more than 60 hormones, most of which cannot be stored in the body in reserve, with the exception of thyroglobulin produced by the thyroid gland, which can be stored for 2 days, as well as vitamin D, which is stored in the liver in reserve.

    For the body to function normally, hormones must be constantly produced. How many hormones the endocrine glands will produce directly depends on the state of the physical, mental, age, as well as the time of day.

    Some types of hormones enter the bloodstream in pulses. Hormones, synthesized in one place and entering the bloodstream, are transported to cells throughout the body. Some hormones are characterized by “moving” to “their” target cells by attaching to transport proteins, carrier proteins.

    Hormones are excreted from the body in their original form with urine and bile. The main amount of hormones is processed in the liver and leaves the body with bile.

    The hypothalamus is the center of regulation of hormone production by endocrine glands and their release into the blood. It is located in the brain, it is in it that hormones called liberins are formed – stimulants of another central endocrine organ – the pituitary gland. Liberins “come” to the pituitary gland from the hypothalamus and stimulate the production of its own hormones by the pituitary gland – tropines.Tropines, in turn, stimulate the production of hormones by the endocrine glands, which are the main link acting in the entire chain.

    In this case, the hormones produced by the endocrine glands contribute to the normal functioning of the hypothalamic-pituitary system. When the concentration of hormones in the blood increases, the liberins by the hypothalamus are “released in reduced circulation”, which leads to a reduction in the production of tropes by the pituitary gland, and this becomes a consequence of a decrease in the production of the hormone. Thus, the hormone itself regulates its own production.

    The scheme described above does not include a description of the entire complex system of regulation of hormonal work in the body, since there is a wide range of significant factors. When work is needed and the amount of hormones is regulated very quickly.

    Manifestation in the function of hormones of disorders is possible in the following cases:

    • Lack of hormone. With a reduction in the production of hormones by the endocrine gland, a heart attack may occur as a result, infections, autoimmune processes, hereditary diseases become more active, tumors may appear.
    • Excessive production of the hormone with its subsequent release into the blood is observed in the case of excessive synthesis of their endocrine glands, as well as when the hormone begins to be produced by tissues (maybe with malignant degeneration), an increased release of hormones from the precursor by the tissues can also be observed. An iatrogenic cause of an increase in the hormone in the blood is considered to be the case when a hormone in the form of a medicine is injected into the body in excess.
    • Synthesis of abnormal hormones by the endocrine glands, which is explained by the presence of genetic abnormalities.
    • Resistance (immunity) to hormones, which manifests itself in an inadequate response of body tissues to normal or increased hormone levels. Causes: heredity, tissue receptor defects, production of antibodies to hormones by the body.

    Endocrine glands:

    1. The pituitary gland is a special gland, as it not only produces hormones, but also affects their production by other glands in the same organism. The pituitary gland is located at the base of the brain and is connected to the hypothalamus by a group of nerve fibers.Together (the pituitary gland and the hypothalamus) control metabolic processes throughout the body, thereby providing all organs with the necessary substances for full activity.

    2. The thyroid gland is located at the level of the larynx.

    3. The parathyroid glands, which are located next to the thyroid gland.

    4. The pancreas is the largest of all. She is two glands in one. Insulin is a hormone produced by the pancreas, diseases due to malfunctioning of the pancreas can be serious, one of which is diabetes.Diseases characteristic of the pancreas are acute pancreatitis, chronic pancreatitis, tumor, lipomatosis. If problems arise with the pancreas, treatment should be started on time, in order to avoid the development of irreversible processes or the transition of the disease into a chronic form. In any case, for problems with the pancreas, treatment is supplemented by a strict diet.

    Violations in any zone of the endocrine system can lead to many disorders of the processes in the body. Endocrinology is a branch of medicine dealing with the study of the endocrine system.It is possible to monitor the state of ES, carry out prophylaxis, diagnose diseases and treat them under the supervision of an endocrinologist. A good endocrinologist will help diagnose the disorder itself and the cause of the disorders in the functioning of the ES and select the right treatment.

    Endocrinology in Irkutsk and consultation with a good endocrinologist are available at the For the Whole Family clinic. Qualified specialists of our clinic will be able to provide detailed consultation, examination and treatment.

    Price list for endocrinologist services

    You can make an appointment at any time convenient for you and receive detailed advice from a specialist:

    1) by phone.: +7 (3952) 390 – 292; 404 – 200 (Railway 2nd, 74)

    2) by phone: +7 (3952) 205-749; 723 – 749 (Karl-Liebknecht, 152)

    Human endocrine system

    The definition and composition of the human endocrine system, consisting of endocrine glands: hypothalamus, pituitary gland, pineal gland, thyroid gland, thymus, pancreas, adrenal glands, gonads, is given and described. A description of the types of hormones and the peculiarities of their functioning in the human body, as well as factors influencing the result of the hormone action, is given.



    The endocrine system is a set of structures: organs, parts of organs, individual cells, secreting highly active regulatory factors – hormones into the blood, lymph and intercellular fluid.

    The relationship between the nervous and endocrine systems

    Biochemical and physiological processes in various organs and tissues proceed in a strictly ordered and coordinated manner due to the presence of regulatory systems that coordinate these processes.Regulatory systems play an especially important role in maintaining metabolic homeostasis during muscle activity, when the intensity of the use of substances increases and their metabolism changes.

    Metabolism (metabolism) is a complex of biochemical and physiological processes that ensures the intake of substances from the environment into the body, their assimilation, transformation in tissues, as well as the removal of metabolic products (metabolites) from the body into the external environment.

    You can read about the relationship between hormones and muscle mass in my book “Hormones and Hypertrophy of Human Skeletal Muscles”

    The main regulatory systems of the human body are the nervous and endocrine systems.There is a close relationship and subordination between the nervous and endocrine systems. The nervous system, through the endocrine system, controls the metabolism, and the endocrine system influences this control. The hypothalamus is the coordinating center of these systems.

    Composition of the endocrine system

    The endocrine system consists of specialized endocrine glands , or endocrine glands. The main endocrine glands are: hypothalamus, pituitary gland, pineal gland, thyroid gland, thymus, pancreas, adrenal glands, gonads (testes, ovaries) (Fig.one).

    Fig. 1

    Types of hormones

    Endocrine glands secrete biologically active substances into the blood – hormones. According to their chemical structure, hormones are divided into three types: steroid, protein-peptide and amino acid derivatives.

    Functioning of hormones in the human body

    Hormones in small amounts enter the bloodstream and, after being transferred by the blood, have a regulatory effect on the metabolism and physiological functions of target organs. In target organ cells, there are special proteins called hormone receptors.These proteins are located either inside the cells of the target organ (if the chemical nature of the hormone is a steroid) or are incorporated into the outer membrane of the cells of the target organ (if the chemical nature of the hormone is protein or amino acid derivatives). Hormone receptors are able to bind only to certain hormones, therefore target organs selectively extract from the flowing blood only those hormones that are necessary for this organ to regulate metabolism in it.

    Factors influencing the effect of the hormone

    The effect of the hormone is influenced by: the concentration of the hormone in the blood; free or associated with a transport protein state of the hormone; the condition of the target tissue; the number of active receptors.


    1. Samsonova, A. V. Hormones and hypertrophy of human skeletal muscles: Textbook. allowance. – SPb: Kinetics, 2019.– 204 pp., Ill.

    Best regards, A.V. Samsonov


    Endocrinology – the science of the structure and function of the endocrine glands, endocrine glands, hormones produced by them, the ways of their formation and action on the human body; and also about diseases caused by dysfunction of these glands or the action of these hormones.A feature of the endocrine glands is the absence of excretory ducts, so the hormones they produce are released directly into the blood. The ratio of hormones depends on: human development, metabolism, puberty, the correct course of pregnancy.

    Endocrine glands are sensitive to changes in the external environment and in the human body, which is manifested by their hypofunction (weakening of hormone production) or hyperfunction (increased secretion of hormones and leads to the development of endocrine diseases.

    More than 60 different hormones are currently known. The amount of hormones synthesized by the endocrine glands depends on the time of day, sleep or wakefulness, mental and physical condition of a person, age.

    Endocrine glands
    Hypothalamus Division of the brain, which is the highest center for the regulation of the autonomic functions of the body.
    Pituitary Endocrine gland that produces tropines – hormones that regulate the activity of other endocrine glands (thyroid, adrenal glands, ovaries and testicles) and indirectly affect the vital functions of the body, which are responsible for growth, metabolism, and reproductive function.
    Thyroid Participates in the regulation of metabolic processes in the body; produces hormones thyroxine and triiodothyronine, which affect the cardiovascular system and are necessary for the normal development and functioning of the central nervous system. In addition, it produces the hormone calcitonin, which regulates calcium metabolism in the body.
    Parathyroid glands Four endocrine glands producing parathyroid hormone.Its production is due to the concentration of calcium in the blood: an increase in calcium levels causes inhibition of the secretion of parathyroid hormone and vice versa. This biologically active substance is involved in the regulation of phosphorus-calcium metabolism and for this function it is a calcitonin antagonist.
    Pancreas The gland, which is both an external and internal secretion gland, produces the hormone insulin and digestive enzymes.Violation of insulin secretion leads to the development of diabetes mellitus.
    Adrenal glands Paired endocrine glands. Located above the upper poles of the kidneys, they produce hormones under the general name corticosteroids, which affect many metabolic processes, vascular tone, and immunity.
    Testicles (testicles) These are paired male sex glands, the main functions of which are sperm production, secretion and release of male sex hormones (androgens) into the blood.
    Ovaries Paired female sex glands. They are the place where female reproductive cells develop and mature, and also produce sex hormones.
    Placenta An organ formed during pregnancy, which provides a connection between the fetus and the mother, and also plays the role of a temporary endocrine gland.
    Thymus A paired gland located on the anterior side of the mediastinum (chest pleura) and involved in the formation and regulation of the body’s immunity.
    Gastrointestinal adipose tissue Gastrointestinal hormones.

    Hormonal disorders

    Hormone deficiency. Occurs with a decrease in the production of hormones by the endocrine gland for various reasons: heart attacks, infections, autoimmune processes, tumors, hereditary diseases, increased binding of hormones to proteins.
    Excess hormones. The reasons may be: excessive synthesis of the endocrine gland, production of hormones by other tissues, increased production of hormones by tissues from its predecessor; can also occur when hormones are prescribed as a drug.
    Synthesis of abnormal hormones by the endocrine glands. This often occurs with congenital genetic abnormalities.
    Resistance (immunity) to hormones. Body tissues do not respond adequately to normal or increased amounts of the hormone in the blood. Immunity of tissues to a hormone has various reasons: the appearance of antibodies to hormones, hereditary nature, a defect in tissue receptors.

    The danger of endocrine diseases lies in the fact that they lead to disruption of the functioning of almost all body systems.Therefore, it is important to notice them in time and start treatment. The main diagnostic method in this case is a blood test to determine the level of hormones. Additionally, ultrasound, computed tomography, etc. are used.

    There are many diseases of the endocrine system. The most common are thyroid disease, diabetes and obesity.

    Diagnostics and treatment in the Clinic of “New Technologies of Medicine”

    Clinic “New Technologies of Medicine” offers services for the diagnosis and treatment of diseases associated with disorders in the endocrine system:

    • Carries out all types of laboratory research: general clinical, hormonal, microbiological, etc.; home blood sampling service is provided
    • Ultrasound examination
    • Management of patients with diabetes mellitus
    • Diagnostics and treatment of diseases of the thyroid gland, adrenal glands, pituitary gland
    • Treatment of climacteric syndrome, infertility

    An endocrinologist should be contacted if you or your loved ones have:

    • Thyroid diseases
    • Diabetes mellitus
    • Osteoporosis
    • Overweight or underweight, sudden changes in body weight over a short period of time
    • Insufficient or rapid growth during puberty; enlargement of hands, feet, nose, change in the shape of the chin in adulthood 90 104
    • Early menopause (up to 53 years of age), pain in joints and large bones, bone fractures resulting from minor injuries
    • Discomfort in the neck, sensation of “lump in the throat”, worse when swallowing
    • Constant or intermittent heartbeat, heart rhythm disturbances, feeling of inner trembling, excessive emotionality, tearfulness
    • Constipation, swelling of the face
    • A sharp deterioration in visual acuity, the appearance of a “veil”, “mesh”, “flies” before the eyes, redness of the eyes, lacrimation, “bulging”
    • Visible signs of goiter
    • Dry mouth, constant thirst, itching in the absence of rash, frequent urination, especially at night
    • General weakness, fatigue, drowsiness, decreased body temperature, numbness of the extremities, memory impairment, frequent headaches
    • Increased blood pressure at a young age (up to 45 years), crisis course of hypertension, not amenable to treatment with a standard set of drugs
    • Dry and thinning skin, hair loss, acne
    • In adolescent girls – early (up to 10 years) onset of menstruation, a long period of stabilization of the cycle. In adult women – any type of menstrual irregularity, miscarriage, discharge from the mammary glands 90 104
    • In men – changes in body hair, erectile dysfunction, discharge from the mammary glands


    Endocrine system – materials for preparing for the exam in Biology

    System of endocrine glands ,
    Hormonal system ,
    Humoral regulation system .

    The author of the article is L.V. Okolnova.

    There are many names, so it immediately becomes clear – a very important system 🙂

    Let’s take it in order.
    “Endocrine” – part of the word “endo” means “internal”, “krinny” – humoral.
    Now let’s translate the term “humoral”
    “Humor” – liquid, moisture.
    Total we get – a system that regulates the body through the liquid. The main fluid of the human body is blood .
    Substances with the help of which such regulation is carried out – hormones.
    In general, this is the most ancient system that even the most simple organisms have.
    They may not even have a circulatory system, but they do have hormones!

    Ecdysones of roundworms


    Human hormones

    Humoral regulation – one of the mechanisms of regulation of vital processes in the body, carried out through the body’s fluids (blood, lymph, tissue fluid, saliva) with the help of hormones secreted by cells, organs, tissues.
    Hormones are biologically active substances of a protein nature, produced in specialized cells of the endocrine glands, entering the internal fluid environment of the body and having a regulating effect on metabolism and physiological functions.

    Human endocrine glands

    Let’s look at the body from top to bottom.




    Pituitary gland

    One of the most important glands of the endocrine system.

    Affects metabolism, growth and reproductive system

    Thyroid-stimulating hormones

    Gonadotropic hormones

    Somatropin, etc.


    The work of this gland is not yet fully understood, but the main functions have already been determined:

    – also affects growth and reproductive system;

    – affects immunity;

    – synchronizes circadian rhythms;

    – inhibits the formation and development of tumors.

    Melatonin et al.

    Thyroid gland

    Regulates iodine content;

    Regulates metabolism and cellular energy level;

    Indirectly affects bone tissue.

    The main hormone is thyroxine

    Parathyroid glands

    Regulates calcium levels

    Parathyroid hormone

    Thymus gland (thymus)

    Gland of the child’s immune system.

    Functional until puberty

    Main hormones: thymosin, thymalin

    Adrenal glands

    Influence the metabolism and homeostasis of the body in stressful conditions.

    Adrenaline and norepinephrine


    Mixed secretion gland.

    It is the endocrine function – the effect on the metabolism, more precisely, on the assimilation of sugar.

    Glucagon and insulin

    Sex glands

    They are also glands of mixed secretion.

    Endocrine function – regulation of the reproductive system.

    Male hormones – androgens;

    Female – estrogens.

    90,000 Endocrine Diseases – Causes, Symptoms and Treatment.

    Endocrine diseases. Where to get treatment in Nizhny Novgorod?

    Endocrine diseases are treated by an endocrinologist in Nizhny Novgorod.

    There are many endocrine diseases.

    How to identify endocrine diseases in Nizhny Novgorod?

    The symptoms of endocrine diseases are insidious and similar to other diseases.

    The endocrine system in the human body regulates the work of internal organs through the production of special substances – hormones.

    Hormones affect the physical parameters of a person, the mental and emotional state of a person and physiological processes in the human body.

    You can determine the level of hormones in your body in Online Clinics!

    If the work of the endocrine system fails, then the process of hormone production is disrupted: hormones are produced in a reduced or increased amount, the processes of transport or absorption of the hormone are disrupted, an abnormal hormone is produced, and resistance against hormonal action is developed.

    Doctors – endocrinologists in Nizhny Novgorod state disturbances in the functioning of the human endocrine system, which lead to various diseases and hormonal imbalances:

    • Hypothyroidism is a disease that affects women more often than men. Hypothyroidism is characterized by a hypofunction of the thyroid gland, in which insufficient hormones are produced. Hypothyroidism leads to a slowdown in metabolic processes.At the initial stage hypothyroidism can be recognized by a state of chronic fatigue.
    • Diabetes mellitus is a disease of complete or partial deficiency of insulin in the blood. Because of this, fats, proteins and carbohydrates are poorly absorbed, and incomplete breakdown of glucose occurs. Diabetes mellitus is life-threatening.
    • Goiter develops due to a violation of the production of thyroid hormones. The main reason for the development of goiter is considered to be a lack of iodine in food.Iodine is essential for the proper functioning of the thyroid gland.
    • Thyrotoxicosis – hyperfunction of the thyroid gland.
    • Autoimmune thyroiditis is a thyroid disease in which the immune system malfunctions. Thyroiditis causes the immune system to perceive thyroid cells as foreign.
    • Hypoparathyroidism leads to cramps in the limbs of a person due to malfunctioning of the parathyroid gland.
    • Hyperparathyroidism – also develops under the influence of malfunctioning of the parathyroid gland.
    • Gigantism is an overproduction of growth hormone that leads to increased but proportionate body development. In adults, the hyperfunction of this hormone provokes an increase in the size of certain parts of the body.

    Symptoms of endocrine diseases, determined in Nizhny Novgorod by a doctor – endocrinologist.

    The endocrine system includes all endocrine glands.

    Among the main symptoms of endocrine diseases in Nizhny Novgorod, doctors – endocrinologists of the Onely Clinic name fatigue, muscle weakness, a sharp change in weight (gaining or losing weight with an unchanged diet), heart pain, heart palpitations, fever, sweating, overexcitation, drowsiness, problems with urination, constant feeling of thirst, high blood pressure, headaches, memory problems, stool disorder.

    All these symptoms can be ignored by the patient for a long time, or can be mistaken for ordinary fatigue.

    Meanwhile, the disease can progress and problems with the immune and hormonal systems increase.

    Only examination by a professional doctor – endocrinologist, passing the necessary tests for hormones will be able to establish the correct diagnosis and identify the cause of the ailment.

    Why do endocrine diseases develop in Nizhny Novgorod?

    There are people who are at risk for endocrine system diseases.

    Doctors – endocrinologists in Nizhny Novgorod call the following risk factors:

    • Age , plus 40.
    • Heredity.
    • Overweight, obesity.
    • Incorrect and sometimes even harmful food.
    • Bad habits: smoking, alcohol, drugs.
    • Physical inactivity: sedentary lifestyle.

    Identification of diseases of the endocrine system in Nizhny Novgorod.

    Why do you need to contact Online Clinics?

    It is impossible to identify an endocrine disease on your own.

    Only a complex of examinations and analyzes will be able to correctly establish the diagnosis.

    Therefore, it is imperative to consult an endocrinologist at the Only Clinic in Nizhny Novgorod when symptoms of endocrine disorders appear.

    Doctor – endocrinologist Onli Clinic conducts a complex of examinations of the endocrine system of the human body, on the basis of which the diagnosis is established:

    1. Visual inspection. A good endocrinologist in Nizhny Novgorod can determine the presence of an endocrine disease by the patient’s appearance.Specifically, after examining the skin, the proportionality of body parts, skin pigmentation, an increase in the thyroid gland, atypical hair growth.
    2. Palpation is necessary to determine the state of the thyroid gland
    3. The endocrinologist will definitely prescribe the patient to take blood tests for sugar and hormones.
    4. Ultrasound of the thyroid gland and ultrasound of the abdominal cavity are quite informative.
    5. In addition, X-ray, CT can be prescribed.

    Many endocrine diseases are hereditary.This is due to mutations at the gene level.

    There is a very high risk for a child to get sick if both or one parent is sick with any endocrine disease.

    Endocrine diseases have implications for all human health.

    Hormones play an essential role in both male and female organisms.

    If the production of hormones is disrupted, this can lead to the most serious consequences for human health.

    Disorders in the work of the endocrine system, in the work of the thyroid gland, hormonal imbalance lead to malfunctioning of internal organs, metabolic processes, functions of endocrine glands, the occurrence of somatic disorders and cosmetic defects.

    At the slightest suspicion of an endocrine disease, an urgent need to consult an endocrinologist in Nizhny Novgorod.

    The presence of an endocrine disease makes a person constantly dependent on taking medications and hormones.

    Endocrine diseases can provoke the development of other “sores”.

    Self-medication of endocrine diseases is life-threatening!

    In One Clinic in the Department of Endocrinology, a doctor-endocrinologist of the highest category, with more than 46 years of experience Shmeleva Serafima Danilovna, is ready to provide assistance.