What are the major glands in the endocrine system. How do hormones regulate bodily functions. What role does the hypothalamus play in hormone production. How does the pituitary gland influence other endocrine glands. Why is the thyroid gland crucial for metabolism.

The Endocrine System: An Overview of Glands and Their Functions

The endocrine system is a complex network of glands that produce and secrete hormones directly into the bloodstream. These chemical messengers play a crucial role in regulating various bodily functions, from metabolism and growth to mood and reproduction. Understanding the components of the endocrine system is essential for comprehending how our bodies maintain homeostasis and respond to internal and external stimuli.

Major Glands of the Endocrine System

The endocrine system comprises several glands, each with specific functions:

• Hypothalamus
• Pituitary gland
• Thyroid gland
• Parathyroid glands
• Adrenal glands
• Pineal gland
• Ovaries (in females)
• Testes (in males)
• Pancreas (part of both endocrine and digestive systems)

These glands work in concert to maintain bodily functions and respond to various environmental and physiological stimuli.

The Hypothalamus: The Control Center of Hormone Production

Located in the lower central part of the brain, the hypothalamus serves as a crucial link between the endocrine system and the nervous system. It plays a pivotal role in hormone regulation by gathering information from various sources and relaying it to the pituitary gland.

Functions of the Hypothalamus

The hypothalamus performs several key functions:

1. Produces chemicals that control hormone release from the pituitary gland
2. Gathers sensory information from the brain, including temperature, light exposure, and emotions
3. Transmits collected information to the pituitary gland, influencing hormone production and release

How does the hypothalamus influence hormone production? By acting as an intermediary between the brain and the pituitary gland, the hypothalamus ensures that hormone secretion is finely tuned to the body’s needs based on environmental and internal cues.

The Pituitary Gland: The Master Regulator of the Endocrine System

Despite its small size, comparable to a pea, the pituitary gland is often referred to as the “master gland” due to its significant influence on other endocrine glands. Located at the base of the brain, it produces and secretes a variety of hormones that control numerous bodily functions.

Key Hormones Produced by the Pituitary Gland

The pituitary gland secretes several important hormones:

• Growth hormone: Stimulates bone and tissue growth, and regulates nutrient metabolism
• Prolactin: Activates milk production in breastfeeding women
• Thyrotropin: Stimulates the thyroid gland to produce thyroid hormones
• Corticotropin: Stimulates the adrenal glands to produce certain hormones
• Antidiuretic hormone: Helps control body water balance through kidney function
• Oxytocin: Triggers uterine contractions during labor
• Endorphins: Reduce pain sensation
• Sex hormones: Signal reproductive organs to produce sex hormones

What makes the pituitary gland so crucial for endocrine function? Its ability to produce and release a wide range of hormones that directly influence other glands and bodily processes makes it a central player in maintaining overall health and homeostasis.

The Thyroid Gland: Regulating Metabolism and Growth

The butterfly-shaped thyroid gland, located in the front part of the lower neck, plays a vital role in regulating metabolism and growth. It produces two primary hormones: thyroxine and triiodothyronine, which control the rate at which cells convert food into energy.

Impact of Thyroid Hormones on Body Functions

Thyroid hormones influence several bodily functions:

1. Regulate metabolic rate
2. Promote bone growth and development
3. Support brain and nervous system development
4. Influence heart rate and body temperature

Why is proper thyroid function essential for overall health? The thyroid’s ability to regulate metabolism affects nearly every organ system in the body, making it crucial for maintaining energy levels, body weight, and proper growth and development, especially in children and adolescents.

Parathyroid Glands: Maintaining Calcium Balance

Attached to the thyroid are four tiny parathyroid glands that work together to regulate calcium levels in the blood. These glands release parathyroid hormone, which works in conjunction with calcitonin produced by the thyroid to maintain calcium homeostasis.

The Role of Parathyroid Hormone in Calcium Regulation

Parathyroid hormone (PTH) influences calcium balance through several mechanisms:

• Increases calcium absorption from the intestines
• Promotes calcium reabsorption in the kidneys
• Stimulates bone resorption to release calcium into the bloodstream
• Increases vitamin D production, which enhances calcium absorption

How does maintaining proper calcium levels impact overall health? Calcium is essential for numerous bodily functions, including bone and tooth health, muscle contraction, nerve signaling, and blood clotting. The parathyroid glands’ ability to regulate calcium levels ensures these processes function optimally.

Adrenal Glands: Stress Response and Hormone Production

The adrenal glands, situated atop each kidney, play a crucial role in the body’s stress response and produce several important hormones. These triangular glands consist of two distinct parts: the adrenal cortex and the adrenal medulla, each responsible for producing different types of hormones.

Adrenal Cortex: Corticosteroid Production

The outer part of the adrenal gland, known as the adrenal cortex, produces hormones called corticosteroids. These hormones serve various functions:

1. Regulate salt and water balance in the body
2. Manage the body’s stress response
3. Influence metabolism
4. Affect immune system function
5. Support sexual development and function

Adrenal Medulla: Catecholamine Production

The inner part of the adrenal gland, called the adrenal medulla, produces catecholamines, including adrenaline (epinephrine) and noradrenaline (norepinephrine). These hormones are crucial for the body’s “fight or flight” response and help regulate:

• Heart rate
• Blood pressure
• Blood sugar levels
• Energy metabolism

Why are the adrenal glands essential for managing stress? The hormones produced by the adrenal glands help the body respond quickly to stressful situations, mobilizing energy resources and preparing the body for action. This stress response is crucial for survival and adaptation to challenging environments.

The Pineal Gland: Regulating Sleep-Wake Cycles

The pineal gland, a small endocrine gland located in the brain, plays a crucial role in regulating sleep-wake cycles and circadian rhythms. Its primary function is the production and secretion of melatonin, a hormone that helps control our sleep patterns.

Melatonin Production and Its Effects

The pineal gland produces melatonin in response to darkness, which helps regulate our internal biological clock. Melatonin production influences several aspects of our physiology:

1. Promotes sleepiness and helps regulate sleep patterns
2. Influences reproductive cycles in some animals
3. May have antioxidant properties
4. Potentially affects mood and seasonal behavior

How does the pineal gland contribute to overall well-being? By regulating sleep-wake cycles through melatonin production, the pineal gland helps maintain proper circadian rhythms, which are essential for good health, cognitive function, and overall quality of life.

Reproductive Glands: Ovaries and Testes

The reproductive glands, namely the ovaries in females and the testes in males, play a crucial role in sexual development, reproduction, and the production of sex hormones. These glands are essential components of the endocrine system and are responsible for many secondary sexual characteristics.

Ovaries: Female Reproductive Glands

The ovaries, located in the female pelvis, produce several important hormones:

• Estrogen: Responsible for female sexual development and regulation of the menstrual cycle
• Progesterone: Prepares the uterus for pregnancy and supports fetal development
• Inhibin: Helps regulate follicle-stimulating hormone (FSH) production

The ovaries also produce and release eggs during ovulation, which is essential for reproduction.

Testes: Male Reproductive Glands

The testes, located in the scrotum, produce testosterone and sperm. Testosterone is responsible for:

1. Male sexual development
2. Sperm production
3. Muscle and bone mass maintenance
4. Red blood cell production
5. Mood and cognitive function

Why are the reproductive glands crucial for human development and health? These glands not only enable reproduction but also play significant roles in physical development, bone health, muscle mass, and overall well-being throughout life.

The Pancreas: A Dual-Function Organ

The pancreas is a unique organ that serves both endocrine and exocrine functions. As part of the endocrine system, it secretes hormones directly into the bloodstream. As an exocrine gland, it produces digestive enzymes that are released into the small intestine.

Endocrine Functions of the Pancreas

The pancreas produces several important hormones:

• Insulin: Regulates blood sugar levels by promoting glucose uptake by cells
• Glucagon: Raises blood sugar levels when they are too low
• Somatostatin: Regulates the release of other hormones
• Pancreatic polypeptide: Helps regulate pancreatic secretions

Exocrine Functions of the Pancreas

As an exocrine gland, the pancreas produces digestive enzymes that help break down:

1. Proteins
2. Carbohydrates
3. Fats
4. Nucleic acids

How does the pancreas contribute to overall health? By regulating blood sugar levels and aiding in digestion, the pancreas plays a crucial role in maintaining metabolic balance and ensuring proper nutrient absorption.

Understanding the intricate workings of the endocrine system and its various glands is crucial for appreciating the complexity of human physiology. From regulating metabolism and growth to managing stress responses and reproductive functions, the endocrine system plays a vital role in maintaining overall health and well-being. By producing and secreting hormones that act as chemical messengers throughout the body, these glands work in harmony to ensure that our bodies function optimally in response to both internal and external stimuli.

As research in endocrinology continues to advance, we gain deeper insights into how hormones influence various aspects of our health, from mood and cognitive function to physical development and disease prevention. This knowledge not only enhances our understanding of human biology but also paves the way for more targeted and effective treatments for endocrine disorders, ultimately improving quality of life for millions of people worldwide.

Endocrine System (for Teens) – Nemours KidsHealth

What Is the Endocrine System?

The endocrine system is made up of glands that make hormones. Hormones are the body’s chemical messengers. They carry information and instructions from one set of cells to another.

The endocrine (pronounced: EN-duh-krin) system influences almost every cell, organ, and function of our bodies.

What Does the Endocrine System Do?

• Endocrine glands release
  hormonesinto the bloodstream. This lets the hormones travel to cells in other parts of the body.
• The endocrine hormones help control mood, growth and development, the way our organs work,
  metabolism, and reproduction.
• The endocrine system regulates how much of each hormone is released. This can depend on levels of hormones already in the blood, or on levels of other substances in the blood, like calcium. Many things affect hormone levels, such as stress, infection, and changes in the balance of fluid and minerals in blood.

Too much or too little of any hormone can harm the body. Medicines can treat many of these problems.

What Are the Parts of the Endocrine System?

While many parts of the body make hormones, the major glands that make up the endocrine system are the:

• hypothalamus
• pituitary
• thyroid
• parathyroids
• adrenals
• pineal body
• the ovaries
• the testes

The pancreas is part of the endocrine system and the digestive system. That’s because it secretes hormones into the bloodstream, and makes and secretes enzymes into the digestive tract.

Hypothalamus: The hypothalamus (pronounced: hi-po-THAL-uh-mus) is in the lower central part of the brain. It links the endocrine system and nervous system. Nerve cells in the hypothalamus make chemicals that control the release of hormones secreted from the pituitary gland. The hypothalamus gathers information sensed by the brain (such as the surrounding temperature, light exposure, and feelings) and sends it to the pituitary. This information influences the hormones that the pituitary makes and releases.

Pituitary: The pituitary (pronounced: puh-TOO-uh-ter-ee) gland is at the base of the brain, and is no bigger than a pea. Despite its small size, the pituitary is often called the “master gland.” The hormones it makes control many other endocrine glands.

The pituitary gland makes many hormones, such as:

• 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 (pronounced: pro-LAK-tin), which activates milk production in women who are breastfeeding
• thyrotropin (pronounced: thy-ruh-TRO-pin), which stimulates the thyroid gland to make thyroid hormones
• corticotropin (pronounced: kor-tih-ko-TRO-pin), which stimulates the adrenal gland to make certain hormones
• antidiuretic (pronounced: an-ty-dy-uh-REH-tik) hormone, which helps control body water balance through its effect on the kidneys
• oxytocin (pronounced: ahk-see-TOE-sin), which triggers the contractions of the uterus that happen during labor

The pituitary also secretes endorphins (pronounced: en-DOR-fins), chemicals that act on the nervous system and reduce feelings of pain. The pituitary also secretes hormones that signal the reproductive organs to make sex hormones. The pituitary gland also controls
ovulationand the menstrual cycle in women.

Thyroid: The thyroid (pronounced: THY-royd) is in the front part of the lower neck. It’s shaped like a bow tie or butterfly. It makes the thyroid hormones thyroxine (pronounced: thy-RAHK-sin) and triiodothyronine (pronounced: try-eye-oh-doe-THY-ruh-neen). These hormones control the rate at which cells burn fuels from food to make energy. The more thyroid hormone there is in the bloodstream, the faster chemical reactions happen in the body.

Thyroid hormones are important because they help kids’ and teens’ bones grow and develop, and they also play a role in the development of the brain and nervous system.

Parathyroids: Attached to the thyroid are four tiny glands that work together called the parathyroids (pronounced: par-uh-THY-roydz). They release parathyroid hormone, which controls the level of calcium in the blood with the help of calcitonin (pronounced: kal-suh-TOE-nin), which the thyroid makes.

Adrenal Glands: These two triangular adrenal (pronounced: uh-DREE-nul) glands sit on top of each kidney. The adrenal glands have two parts, each of which makes a set of hormones and has a different function:

1. The outer part is the adrenal cortex. It makes hormones called corticosteroids (pronounced: kor-tih-ko-STER-oydz) that help control salt and water balance in the body, the body’s response to stress, metabolism, the immune system, and sexual development and function.
2. The inner part is the adrenal medulla (pronounced: muh-DUH-luh). It makes catecholamines (pronounced: kah-tuh-KO-luh-meenz), such as epinephrine (pronounced: eh-puh-NEH-frun). Also called adrenaline, epinephrine increases blood pressure and heart rate when the body is under stress.

Pineal: The pineal (pronounced: pih-NEE-ul) body, also called the pineal gland, is in the middle of the brain. It secretes melatonin (pronounced: meh-luh-TOE-nin), a hormone that may help regulate when you sleep at night and when you wake in the morning.

Reproductive Glands: The gonads are the main source of sex hormones. Most people don’t realize it, but both guys and girls have gonads. In guys the male gonads, or testes (pronounced: TES-teez), are in the scrotum. They secrete hormones called androgens (pronounced: AN-druh-junz), the most important of which is
testosterone(pronounced: tess-TOSS-tuh-rone). These hormones tell a guy’s body when it’s time to make the changes associated with puberty, like penis and height growth, deepening voice, and growth in facial and pubic hair. Working with hormones from the pituitary gland, testosterone also tells a guy’s body when it’s time to make sperm in the testes.

A girl’s gonads, the ovaries (pronounced: OH-vuh-reez), are in her pelvis. They make eggs and secrete the female hormones
estrogen(pronounced: ESS-truh-jen) and
progesterone(pronounced: pro-JESS-tuh-rone). Estrogen is involved when a girl starts puberty. During puberty, a girl will have breast growth, start to accumulate body fat around the hips and thighs, and have a growth spurt. Estrogen and progesterone are also involved in the regulation of a girl’s menstrual cycle. These hormones also play a role in pregnancy.

Pancreas: The pancreas (pronounced: PAN-kree-us) makes insulin (pronounced: IN-suh-lin) and glucagon (pronounced: GLOO-kuh-gawn), which are hormones that control the level of glucose, or sugar, in the blood. Insulin helps keep the body supplied with stores of energy. The body uses this stored energy for exercise and activity, and it also helps organs work as they should.

How Can I Help Keep My Endocrine System Healthy?

To help keep your endocrine system healthy:

• Get plenty of exercise.
• Eat a nutritious diet.
• Go for regular medical checkups.
• Talk to the doctor before taking any supplements or herbal treatments.
• Let the doctor know about any family history of endocrine problems, such as diabetes or thyroid problems.

When Should I Call the Doctor?

Let the doctor know if you:

• drink a lot of water but are still thirsty
• have to pee often
• have frequent belly pain or nausea
• are very tired or weak
• are gaining or losing a lot of weight
• have tremors or sweat a lot
• are constipated
• are not growing or developing as expected

Medically reviewed by: Larissa Hirsch, MD

Date reviewed: October 2018

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

Written by Barbara Brody

• What Is the Endocrine System?
• What Is a Gland?
• Endocrine System Functions
• Parts of the Endocrine System
• Health Issues
• Endocrine System Disorders
• More

The endocrine system is a network of glands in your body that make the hormones that help cells talk to each other. They’re responsible for almost every cell, organ, and function in your body.

If your endocrine system isn’t healthy, you might have problems developing during puberty, getting pregnant, or managing stress. You also might gain weight easily, have weak bones, or lack energy because too much sugar stays in your blood instead of moving into your cells where it’s needed for energy.

A gland is an organ that makes and puts out hormones that do a specific job in your body. Endocrine and exocrine glands release the substances they make into your bloodstream.

Your endocrine system:

• Makes hormones that control your moods, growth and development, metabolism, organs, and reproduction
• Controls how your hormones are released
• Sends those hormones into your bloodstream so they can travel to other body parts

Many glands make up the endocrine system. The hypothalamus, pituitary gland, and pineal gland are in your brain. The thyroid and parathyroid glands are in your neck. The thymus is between your lungs, the adrenals are on top of your kidneys, and the pancreas is behind your stomach. Your ovaries (if you’re a woman) or testes (if you’re a man) are in your pelvic region.

• Hypothalamus. This organ connects your endocrine system with your nervous system. Its main job is to tell your pituitary gland to start or stop making hormones.
• Pituitary gland. This is your endocrine system’s master gland. It uses information it gets from your brain to tell other glands in your body what to do. It makes many important hormones, including growth hormone; prolactin, which helps breastfeeding moms make milk; antidiuretic hormone(ADH) (vasopressin), which controls blood pressure and helps control body water balance through its effect on the kidney, corticotropin /ACTH: Adrenocorticotrophic hormone. which stimulates the adrenal gland to make certain hormones, thyroid-stimulating hormone (TSH), which stimulates the production and secretion of thyroid hormones, oxytocin which helps in milk ejection during breast feeding; and luteinizing hormone, which manages estrogen in women and testosterone in men.
• Pineal gland. It makes a chemical called melatonin that helps your body get ready to go to sleep.
• Thyroid gland. This gland makes thyroid hormone, which controls your growth and metabolism. If this gland doesn’t make enough (a condition called hypothyroidism), everything happens more slowly. Your heart rate might slow down. You could get constipated. And you might gain weight. If it makes too much (hyperthyroidism), everything speeds up. Your heart might race. You could have diarrhea. And you might lose weight without trying. The thyroid gland also produces the hormone calcitonin, which may contribute to bone strength by helping calcium to be incorporated into bone.
• Parathyroid. This is a set of four small glands behind your thyroid. They play a role in bone health. The glands control your levels of calcium and phosphorus.
• Thymus. This gland makes white blood cells called T-lymphocytes that fight infection and are crucial as a child’s immune system develops. The thymus starts to shrink after puberty.
• Adrenals. Best known for making the “fight or flight” hormone adrenaline (also called epinephrine), these two glands also make hormones called corticosteroids. They affect your metabolism heart rate, oxygen intake, blood flow, and sexual function, among other things.
• Pancreas. This organ is part of both your digestive and endocrine systems. It makes digestive enzymes that break down food. It also makes the hormones insulin and glucagon. These ensure you have the right amount of sugar in your bloodstream and your cells.
• If you don’t make insulin, which is the case for people with type 1 diabetes, your blood sugar levels can get dangerously high. In type 2 diabetes, the pancreas usually makes some insulin but not enough.
• Ovaries. In women, these organs make estrogen and progesterone. These hormones help develop breasts at puberty, regulate the menstrual cycle, and support a pregnancy.
• Testes. In men, the testes make testosterone. It helps them grow facial and body hair at puberty. It also tells the penis to grow larger and plays a role in making sperm.

As you get older, it’s natural to notice some things related to your endocrine system. Your metabolism tends to slow down. So you might gain weight even though you haven’t changed how you eat or exercise. Hormonal shifts also explain, at least in part, why you’re more likely to have heart disease, osteoporosis, and type 2 diabetes as you age.

No matter how old you are, stress, infections, and being around certain chemicals can also mess with parts of your endocrine system. And genetics or lifestyle habits can increase your chances of an endocrine disorder like hypothyroidism, diabetes, or osteoporosis.

• Acromegaly. Sometimes the pituitary gland makes too much growth hormone and your bones get bigger. It usually affects your hands, feet, and face. It usually starts in middle age.
• Adrenal insufficiency. When you have this, your adrenal glands don’t make enough of certain hormones, like cortisol, which controls stress.
• Cushing’s disease. In this, your body makes too much cortisol. You could gain weight, get stretch marks, bruise easily at first, then get weakened muscles and bones and possibly develop a hump on your upper back.
• Hyperthyroidism. This is when your thyroid gland makes more hormones than your body needs. You might hear it called overactive thyroid. It makes your system run fast and you might feel nervous, lose weight, and have a rapid heartbeat or trouble sleeping.
• Hypothyroidism. When your body doesn’t make enough thyroid hormone, your system slows down. You might feel tired, gain weight, have a slow heartbeat, and get joint and muscle pains.
• Hypopituitarism. Sometimes your pituitary gland doesn’t make enough of certain hormones and your adrenal and thyroid glands can’t work right.
• Multiple endocrine neoplasia. This is a group of disorders that affect your endocrine system. It causes tumors on at least two endocrine glands or in other organs and tissues.
• Polycystic ovary syndrome. An imbalance of reproductive hormones can cause your ovaries to either not make an egg or not release it during ovulation. This can throw off your periods, cause acne, and make hair to grow on your face or chin.
• Precocious puberty. When glands that control reproduction don’t work properly, some kids start puberty abnormally early — around 8 in girls and 9 in boys.

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Home / Endocrinology – Endocrine system

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 these processes.

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

Of course, the functions of the endocrine system are vital for a person. It is involved in the chemical regulation of organs, systems and the body as a whole.

It is involved (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 psycho-emotional state of a person.

What are these hormones? Hormones are carriers that enter the bloodstream to 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 – the heart, liver, brain.

To date, 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 reserve in the liver.

In order for the body to function properly, hormones must be constantly produced. How many hormones the endocrine glands will produce directly depends on the state of the physical, mental, age, and time of day.

Some types of hormones enter the blood in impulses – portions. 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 for regulating the production of hormones by the 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 pituitary gland to produce its own hormones – tropins. Tropins, in turn, stimulate the production of hormones by the endocrine glands, which are the main link in the entire chain.

At the same time, 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, liberins are “released in reduced quantities” by the hypothalamus, which leads to a reduction in the production of tropins by the pituitary gland, and this is the result of a decrease in hormone production. 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 are a wide range of significant factors. When work is needed and the amount of hormones is regulated very quickly.

Hormone dysfunction may occur in the following cases:

• Hormone deficiency. With a reduction in the production of hormones by the endocrine gland, a heart attack can occur as a result, infections, autoimmune processes, hereditary diseases are activated, and tumors may appear.
• Excessive production of the hormone with its subsequent release into the blood is observed in case of excessive synthesis of them by the endocrine glands, and also when the hormone begins to be produced by tissues (may be during malignant degeneration), an increased release of hormones from the precursor by tissues can also be observed. An iatrogenic cause of an increase in the hormone in the blood is considered to be the case when the hormone is administered in excess in the form of a medicine.
• 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 elevated levels of hormones. Causes: heredity, defects in tissue receptors, 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 influences 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 and hypothalamus) control metabolic processes throughout the body, thereby providing all organs with the necessary substances for full-fledged activity.

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

3. 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 malfunction of the pancreas can be serious, one of which is diabetes mellitus. Diseases characteristic of the pancreas are acute pancreatitis, chronic pancreatitis, tumor, lipomatosis. If there are problems with the pancreas, treatment should be started on time, in order to avoid the development of irreversible processes or the transition of the disease to a chronic form. In any case, for problems with the pancreas, treatment is supplemented by a strict diet.

Violations in any area of ​​the endocrine system can lead to many violations of processes in the body. Endocrinology is a branch of medicine that deals with the study of the endocrine system. You can monitor the state of ES, carry out prevention, diagnose diseases and treat them under the supervision of an endocrinologist. A good endocrinologist will help diagnose the disorder itself and the cause of 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 clinic “For the whole family”. Qualified specialists of our clinic will be able to conduct a detailed consultation, examination and treatment.

Price list for endocrinologist services

reception and get detailed advice from a specialist:

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

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

Biology Endocrine glands and their functions

Human organ systems perform strictly defined functions, and in order for the body to exist as a whole, it is necessary to regulate and coordinate this complex work. This regulation is carried out by the nervous and humoral systems. Humoral regulation is carried out due to the release of hormones into the internal environment of the body, which are produced by the endocrine glands.

Endocrine glands, or endocrine glands, do not have excretory ducts. The products of their vital activity – hormones – they secrete into the internal environment of the body: into the blood, lymph or tissue fluid. it is formed by endocrine glands. While the glands of external secretion – sweat, salivary, sebaceous, gastric – secrete the products of their vital activity into the external environment or body cavities.

Entering the blood, the hormone is distributed throughout the body and carries out humoral regulation of the functions of organs and tissues, changing their activity, stimulating or inhibiting their work.

The most important endocrine glands are the thyroid, parathyroid, thymus, adrenal and pituitary glands.

There are also glands of mixed secretion in the body, which produce several waste products. Some of them enter the bloodstream, and some go through the ducts into the cavity of the internal organs. This type of gland includes the pancreas and gonads.

The product of the vital activity of the endocrine glands is a hormone. The term “hormone” (from the Greek “I excite”, “I induce”) was introduced into practice by W. Bayliss and E. Starling. In January 1902, they conducted an experiment that convincingly proved the participation of the humoral factor in the regulation of the secretory activity of the pancreas. According to Bayliss and Starling, a hormone is any substance normally produced by the cells of any part of the body and carried by the blood to the distant parts on which it acts.

Currently, hormones are defined as highly active substances formed in the endocrine glands, entering the bloodstream and exerting a regulatory influence on the functions of organs and body systems remote from their place of secretion.

According to the chemical structure, hormones are divided into:

– hormones – derivatives of amino acids;

– protein and polypeptide hormones;

– steroid hormones.

According to the physiological effect – on launchers and performers. Trigger hormones (activators of the activity of other endocrine glands) include neurohormones of the hypothalamus and tropic hormones of the pituitary gland. Hormones-performers have a direct effect on the functions of the body.

Hormones are distinguished by a strict specificity of action – the reactions of organs, tissues and cells to them are strictly selective. Hormones act even in negligible amounts, but they are quickly destroyed, and therefore must be synthesized by the glands as needed and enter the bloodstream.

The thyroid gland is the largest of the endocrine glands, its mass is 16-23 g. It is located on both sides of the trachea just below the thyroid cartilage of the larynx. Thyroid hormones (thyroxine and triiodothyronine) contain iodine. Its intake with water and food is a necessary condition for the normal functioning of the gland.

Thyroid hormones regulate metabolism, enhance oxidative processes in cells and the breakdown of glycogen in the liver, affect the growth, development and differentiation of tissues, as well as the activity of the nervous system.

The adrenal glands are paired glands adjacent to the upper poles of the kidneys. Like the kidneys, the adrenal glands have two layers: the outer one is the cortical layer, and the inner one is the medulla, which are independent secretory organs. They produce different hormones with different patterns of action.

The cells of the cortical layer synthesize cortisol and corticosterone, which regulate mineral, carbohydrate, protein and fat metabolism. So, with their participation, the level of sodium and potassium in the blood is regulated, a certain concentration of glucose is maintained, the formation and deposition of glycogen in the liver and muscles increases. The last two functions of the adrenal glands are performed in conjunction with pancreatic hormones.

The adrenal medulla produces adrenaline and norepinephrine, which are released during strong emotions – anger, fear, pain, danger. The entry of these hormones into the blood causes a rapid heartbeat, narrowing of blood vessels, increased blood pressure, increased breakdown of glycogen in liver cells and muscles to glucose, inhibition of intestinal motility, relaxation of bronchial muscles, increased excitability of retinal receptors, auditory and vestibular apparatus. As a result, the functions of the body are rebuilt, forces are mobilized to endure stressful situations.

The pancreas is a mixed secretion gland. It has special islet cells that produce insulin and glucagon, which regulate carbohydrate metabolism in the body. So, insulin increases the consumption of glucose by cells, promotes the conversion of glucose into glycogen, thus reducing the amount of sugar in the blood. Due to the action of insulin, the blood glucose content is maintained at a constant level, favorable for the flow of vital processes.

Another pancreatic hormone – glucagon – is an insulin antagonist, has the opposite effect, that is, it enhances the breakdown of glycogen to glucose, increasing its content in the blood.

The gonads, the testes, or testicles in men and the ovaries in women, are glands of mixed secretion. The testicles produce androgens and the ovaries produce estrogens. They stimulate the development of reproductive organs, the maturation of germ cells and the formation of secondary sexual characteristics, that is, the structural features of the skeleton, the development of muscles, the distribution of hairline and subcutaneous fat, the structure of the larynx, the timbre of the voice in men and women.

The most important gland of the human endocrine system is the pituitary gland, or the lower appendage of the brain weighing only 0.5 g. It is located at the base of the brain – in the so-called “Turkish saddle”. The pituitary gland produces hormones that stimulate the functions of other endocrine glands.

In the pituitary gland, there are two main sections: the anterior lobe – adenohypophysis and the posterior – neurohypophysis, each of them produces certain hormones. So, in the anterior pituitary gland, hormones are produced that stimulate the synthesis and secretion of thyroid hormones (thyrotropin), adrenal glands (adrenocorticotropin), gonads (gonadotropin), as well as growth hormone (somatotropin).

Vasopressin and oxytocin are synthesized in the posterior pituitary gland. Vasopressin, or antidiuretic hormone, regulates water metabolism and vascular tone. Oxytocin increases the tone of the smooth muscles of the uterus, regulates the birth act and the secretion of milk by the mammary glands.

The pituitary gland is located directly below the hypothalamus and is connected to it by a funnel and stalk. The hypothalamus is a part of the brain that has properties of the nervous and endocrine systems. The hypothalamus receives an extensive flow of information from the senses and internal organs. The composition of the neurosecretory nuclei of the hypothalamus includes the so-called large and small cell nuclei. The former secrete oxytocin and vasopressin, which are transported along the nerve trunks to the posterior pituitary gland, accumulate there and are used as needed. Other functions are performed by the small cell nuclei of the hypothalamus. They are able to develop the so-called releasing factors (allowing factors). Releasing factors through the venous system reach the pituitary gland and regulate the release of hormones of the latter.

All endocrine glands are interconnected. Hormones produced by some glands affect the activity of other glands. This provides a unified system of coordination, which is carried out according to the feedback principle: a decrease in the level of a peripheral hormone in the blood leads to an increase in the secretion of the corresponding tropic hormone, and an increase in the level of a peripheral hormone causes inhibition of the secretion of the tropic hormone.