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Gland that regulates metabolism: What is the Endocrine System?

Treatment of Endocrine Disorders | Orlando

What is the endocrine system?

The endocrine system is a network of glands positioned throughout the human body that controls a variety of functions. Each gland is responsible for producing certain types of hormones that allow cells to work together in performing necessary functions for life. 

Almost every cell, organ, and system function throughout the body relies on a healthy, working endocrine system. Not only does the human body thrive because of its endocrine network, but so do mammals, birds, and other vertebrates. Each living being relies on the release of hormones to facilitate communication between internal systems. 

Hormone levels and the endocrine system are responsible for monitoring blood pressure, extracting energy from ingested nutrients, initiating appetite, development of sex organs, and so much more.

What are the endocrine glands and what do they do?

The endocrine system is made up of a variety of separate glands that are responsible for individual processes and contribute to the much larger puzzle. They are as follows: 

  • Hypothalamus: As part of the human brain, the hypothalamus forms a bridge between our nervous system and our endocrine system, ensuring the two work well together. This crucial gland has the power to stop and start the release of hormones throughout the body based on hormone levels. In doing this, the hypothalamus maintains its precise balance, or homeostasis. 
  • Pineal Gland: Also called, the third eye, the function of this gland was just recently discovered. Situated deep inside the brain, the pineal gland makes melatonin – an essential factor in maintaining a healthy circadian rhythm, or sleep cycle. The pineal gland releases this hormone in accordance with light exposure, ensuring our internal clocks are set in accordance with the rising and setting sun. Our “third eye” also releases select reproductive hormones. 
  • Pituitary Gland: Often cited as the “master gland”, the pituitary gland is pea-sized and controls much of the hormone release within our bodies. The pituitary gland is credited with controlling our metabolism, growth, reproduction, blood pressure, and more. 
  • Thyroid gland: This regulates our metabolism, growth, and general development of the human body as it progresses from childhood into adulthood. By releasing a steady amount of hormones into the blood stream, the thyroid keeps our metabolic rate stable, which then promotes healthy digestion. 
  • Adrenal glands: These cortisol-producing glands sit atop the kidneys and are vital to successful endocrine system functions. The hormones they release help the body respond to external stressors. 
  • Parathyroid gland: Responsible for bone health and density, these four small glands sit behind the thyroid and control levels of phosphorus and calcium. 
  • Thymus: After puberty, this piece of the endocrine system begins to shrink. It still remains responsible for releasing white blood cells that fight infection but is much more active during the early years of development.  
  • Pancreas: Essential to the digestive system and the endocrine system, the pancreas produces insulin and glucagon, which ensure you have an appropriate amount of sugar in the bloodstream. 
  • Gonads: Present in males as testes and in females as ovaries, the gonads regulate reproductive development, cycles, and behaviors. 

What are endocrine system disorders?

Endocrine system disorders are vast and varied, affecting the endocrine glands and thus the entire internal organ system. Some disorders include: 

  • Gigantism/Growth Issues. Too much growth hormones released during a child’s developmental stages can result in gigantism. An overactive or under-active pituitary gland can stimulate or stunt a child’s growth. 
  • Adrenal insufficiency. Also called Addison’s disease, this occurs when the adrenal glands fail to produce sufficient levels of cortisol and aldosterone. Symptoms of Addison’s disease may include fatigue, muscle weakness, nausea, and vomiting. 
  • Cushing’s disease. An overactive adrenal gland or pituitary gland can result in Cushing’s disease, which can cause weight gain, excessive hairiness, sweating, insomnia, swelling, and more. 
  • Hyperthyroidism. When the thyroid kicks into overdrive and generates too much of its hormone, one may experience weight loss, increased heart rate, or an autoimmune disorder called Grave’s disease. 
  • Hypothyroidism. The lack of thyroid hormones can cause hypothyroidism and stunt growth development in children or lead to constipation, dry skin, and depression in adults. 

Causes of Endocrine disorders include but are not limited to: 

  • Infections. Certain infections, like tuberculosis, can cause endocrine disorders. 
  • Tumors. When tumors grow on the glands within the endocrine system, they can inhibit the production of necessary hormones. Tumors may also be cancerous and spread to other organs within the body. 
  • Autoimmune diseases. HIV, Lupus, or other autoimmune disorders can cause the immune system to attack itself, causing damage to glands within the endocrine system. 
  • Genetic disorders. There are a variety of genetic disorders that can cause damage to the endocrine system. One of the most common is Multiple Endocrine Neoplasia (MEN) which causes excess growth of skin on various endocrine glands. 

What are the treatments for endocrine disorders?

Treatments for endocrine disorders vary depending on the disorder and the patient’s medical history. For endocrine orders that are related to tumor growth, surgery may be a potential treatment. Other endocrine issues may be treated in the following ways: 

  • Hormone suppression. Overactive glands that can result in gigantism, hyperthyroidism, Cushings disease, and the link, can be managed through the administration of prescription medication. Those suffering from these types of endocrine disorders will need to be on a structured health care plan for the rest of their lives but are able to maintain a semblance of normalcy and a high quality of life. 
  • Hormone replacement therapy. Endocrine disorders that cause a lack of hormone release can be managed through hormone replacement therapies. Careful, professionally supervised health care can help the endocrine system get back on the right track and release hormones appropriately. 

UCF Health employs a team of experts who specialize in diagnosing and treating adrenal disorders. In collaboration with knowledgeable medical professionals, doctors at UCF Health can help evaluate your symptoms and guide you to a healthier, fruitful existence. For advanced Orlando Endocrinology Services or other UCF Health services, visit our patient portal to schedule an appointment.

endocrine system | anatomy | Britannica

endocrine system, any of the systems found in animals for the production of hormones, substances that regulate the functioning of the organism. Such a system may range, at its simplest, from the neurosecretory, involving one or more centres in the nervous system, to the complex array of glands found in the human endocrine system.

Comparative endocrinologists investigate the evolution of endocrine systems and the role of these systems in animals’ adaptation to their environments and their production of offspring. Studies of nonmammalian animalshave provided information that has furthered research in mammalian endocrinology, including that of humans. For example, the actions of a pituitary hormone, prolactin, on the control of body water and salt content were first discovered in fishes and later led to the demonstration of similar mechanisms in mammals. The mediating role of local ovarian secretions (paracrine function) in the maturation of oocytes (eggs) was discovered in starfishes and only later extended to vertebrates. The important role of thyroid hormones during embryonic development was first studied thoroughly in tadpoles during the early 1900s. In addition, the isolation and purification of many mammalian hormones was made possible in large part by using other vertebrates as bioassay systems; that is, primitive animals have served as relatively simple, sensitive indicators of the amount of hormone activity in extracts prepared from mammalian endocrine glands. Finally, some vertebrate and invertebrate animals have provided “model systems” for research that have yielded valuable information on the nature of hormone receptors and the mechanisms of hormone action. For example, one of the most intensively studied systems for understanding hormone actions on target tissues has been the receptors for progesterone and estrogens (hormones secreted by the gonads) from the oviducts of chickens.

An understanding of how the endocrine system is regulated in nonmammals also provides essential information for regulating natural populations or captive animals. Artificial control of salmon reproduction has had important implications for the salmon industry as a whole. Some successful attempts at reducing pest insect species have been based on the knowledge of pheromones. Understanding the endocrinology of a rare species may permit it to be bred successfully in captivity and thus prevent it from becoming extinct. Future research may even lead to the reintroduction of some endangered species into natural habitats.

Evolution of endocrine systems

The most primitive endocrine systems seem to be those of the neurosecretory type, in which the nervous system either secretes neurohormones (hormones that act on, or are secreted by, nervous tissue) directly into the circulation or stores them in neurohemal organs (neurons whose endings directly contact blood vessels, allowing neurohormones to be secreted into the circulation), from which they are released in large amounts as needed. True endocrine glands probably evolved later in the evolutionary history of the animal kingdom as separate, hormone-secreting structures. Some of the cells of these endocrine glands are derived from nerve cells that migrated during the process of evolution from the nervous system to various locations in the body. These independent endocrine glands have been described only in arthropods (where neurohormones are still the dominant type of endocrine messenger) and in vertebrates (where they are best developed).

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It has become obvious that many of the hormones previously ascribed only to vertebrates are secreted by invertebrates as well (for example, the pancreatic hormone insulin). Likewise, many invertebrate hormones have been discovered in the tissues of vertebrates, including those of humans. Some of these molecules are even synthesized and employed as chemical regulators, similar to hormones in higher animals, by unicellular animals and plants. Thus, the history of endocrinologic regulators has ancient beginnings, and the major changes that took place during evolution would seem to centre around the uses to which these molecules were put.

Vertebrates (phylum Vertebrata) are separable into at least seven discrete classes that represent evolutionary groupings of related animals with common features. The class Agnatha, or the jawless fishes, is the most primitive group. Class Chondrichthyes and class Osteichthyes are jawed fishes that had their origins, millions of years ago, with the Agnatha. The Chondrichthyes are the cartilaginous fishes, such as sharks and rays, while the Osteichthyes are the bony fishes. Familiar bony fishes such as goldfish, trout, and bass are members of the most advanced subgroup of bony fishes, the teleosts, which developed lungs and first invaded land. From the teleosts evolved the class Amphibia, which includes frogs and toads. The amphibians gave rise to the class Reptilia, which became more adapted to land and diverged along several evolutionary lines. Among the groups descending from the primitive reptiles were turtles, dinosaurs, crocodilians (alligators, crocodiles), snakes, and lizards. Birds (class Aves) and mammals (class Mammalia) later evolved from separate groups of reptiles. Amphibians, reptiles, birds, and mammals, collectively, are referred to as the tetrapod (four-footed) vertebrates.

The human endocrine system is the product of millions of years of evolution. and it should not be surprising that the endocrine glands and associated hormones of the human endocrine system have their counterparts in the endocrine systems of more primitive vertebrates. By examining these animals it is possible to document the emergence of the hypothalamic-pituitary-target organ axis, as well as many other endocrine glands, during the evolution of fishes that preceded the origin of terrestrial vertebrates.

Endocrine System – an overview


The endocrine system consists of a number of interacting effector–target organ feedback pathways. The placental-fetal endocrine tissues sustain the intrauterine milieu and promote adaptation for postnatal life. During this perinatal transition, the organism shifts from dependence on the placenta to independent homeostatic regulation (Gluckman et al, 1999). The functional development of the endocrine glands and hormonal responsiveness of target tissues are influenced by fetal genotype, maternal genotype, maternal prepregnancy and pregnancy health and nutrition, and pregnancy-associated and other maternal stresses.

Much of the understanding about the developmental biology of the endocrine system is derived from large-animal fetal physiology models and gene manipulation in mice. An important caveat in comparing ontogenic studies in different species, however, is to consider the similarities with and differences from human fetuses and newborns. A critical point for interspecies comparisons is the relationship between birth and the maturational state of the neonate. Different species (and different organ systems of a single species) may be classified either as immature (altricial) or more developed (precocial). The human newborn has a relatively mature (precocial) brain and lung and mature neuroendocrine and parathyroid-renal pathways but is relatively clumsy—that is, motorically immature (altricial).

The human fetal endocrine system develops more or less independently of maternal endocrine influences. This separation is possible because the placenta is an efficient barrier to fetal access to most maternal hormones including steroids, sterols, peptides, glycoproteins, and catechols. Nevertheless, transplacental passage of even minute amounts of several maternal hormones can be essential for normal fetal development. For example, in human fetuses with congenital hypothyroidism (Chapter 92, on thyroid disorders), maternal-fetal transfer of thyroid hormone (T4) may result in neonatal plasma levels 25% to 50% of those in normal newborns (Vulsma et al, 1989). Therefore, the outcome in congenital hypothyroidism is generally good when T4 replacement is initiated within the first 2 weeks after birth. In contrast, maternal hypothyroidism during pregnancy adversely affects neurodevelopmental outcome in the offspring (Haddow et al, 1999), and the combination of severe maternal and fetal hypothyroxinemia results in profound neurodevelopmental disability (Yasuda et al, 1999).

Disturbances in transplacental substrate transfer, such as that of calcium (Chapter 89) and glucose (Chapter 93), also may modify the development of fetal and neonatal hormonal pathways. Maternal immunoglobins and certain therapeutic agents also are transported to the fetus. In the example of Graves disease, transplacental transfer of maternal thyroid-stimulating antibodies may cause fetal hyperthyroidism, and maternal antithyroid medications (propylthiouracil, methimazole) in sufficient doses suppress fetal thyroid function (Chapter 92).

Quia – Health Ch. 18 Vocabulary

endocrine glands ductless-or tubeless-organs or groups of cells that secrete hormones directly into the bloodstream
hormones chemical substances taht are produced in glands and help regulate many of your body’s functions
thyroid gland produces hormones that regulate metabolism, body heat, and bone growth
parathyroid glands produces a hormone that regulates the body’s calcium and phosphorus balance
pancreas a gland that serves both the digestive and the endocrine systems
pituitary gland regulates and controls the activities of all of the otehr endocrine glands
gonads another for the ovaries and testes
adrenal glands glands that help the body recover from stress and respond to emergencies
reproductive system the system of organs involved in producing offspring
sperm the male reproductive cells
testosterone the male sex hormone
testes two small glands that produce sperm, also called the testicles
scrotum an external skin sac
penis a tube-shaped organ that extends from the trunk of the body just above the testes
semen a thick fluid containing sperm and other secretions from the male reproductive system
sterility the inability to reproduce
ova female reproductive cells
uterus a hollow, muscular, pear-shaped organ inside a female’s body
ovaries the female sex glands that store the ova and produce female sex hormones
ovulation the process of releasing a mature ovum into the fallopian tube each month
fallopian tubes a pair of tubes with fingerlike projections that draw in the ovum
vagina a muscular, elastic passageway that extends from the uterus to the outside of the body
cervix the opening to the uterus
menstruation shedding of the uterine lining

Metabolic Leader | Adrenal Glands

There are normally two adrenal glands, triangular-shaped organs that measure about 1. 5 by 3 inches, which are located on top of each kidney. When you think of adrenal glands, stress might come to mind. The adrenal glands are arguably best known for secreting the stress hormones, which rapidly prepare your body to spring into action (flight, fright, fight). But the adrenal glands contribute to your health even at times when your body isn’t under extreme stress. In fact, they release hormones that are essential for you to live.

Adrenal Glands Hormones

An adrenal gland is made up of two distinct parts:
• The adrenal cortex – the outer part of the gland produces glucocorticoid hormones that are vital to life, such as cortisol (which helps regulate metabolism and helps your body respond to stress) and mineralocorticoids, such as aldosterone (which helps control blood pressure by adjusting water and salt levels in the bloodstream).
• The adrenal medulla – the inner part of the gland produces other hormones, such as adrenaline and noradrenaline (which helps your body react to stress).

Adrenal Cortex Hormones

The adrenal cortex hormones, glucocorticoids and mineralocorticoids, are essential hormones that maintain adequate blood flow which maintains oxygen and nutrients to all cells. The release of glucocorticoids is triggered by the hypothalamus and pituitary gland. When the hypothalamus produces corticotrophin-releasing hormone (CRH), it stimulates the pituitary gland to release adrenocorticotrophic hormone (ACTH). These hormones, in turn, alert the adrenal glands to produce glucocorticoid hormones. Mineralocorticoids are mediated by different signals triggered by the kidney.

Hormones released by the adrenal cortex include:
• Hydrocortisone: Commonly known as cortisol, it regulates how the body converts fats, proteins, and carbohydrates to energy. It also helps regulate blood pressure and cardiovascular function.
• Corticosterone: This hormone works with hydrocortisone to regulate immune response and suppress inflammatory reactions.
• Aldosterone: is the mineralocorticoid which maintains the right balance of salt and water while helping control blood pressure.
• Sex Steroids: are released in very small amounts of male and female sex hormones. However, their impact is usually overshadowed by the greater amounts of hormones (such as estrogen and testosterone) released by the ovaries and testes.

Unlike the adrenal cortex, the adrenal medulla does not make hormones which are essential or needed to live. The hormones of the adrenal medulla are released when the sympathetic nervous system is stimulated, which occurs when you are stressed by physical or emotional reasons. You may be familiar with the fight-fright-flight when your body encounters a threatening (stressful) situation. The hormones of the adrenal medulla contribute to the response.

Hormones secreted by the adrenal medulla are:
• Epinephrine: Most people know epinephrine by its other name – adrenaline. This hormone rapidly responds to stress by increasing your heart rate and increasing blood flow to the muscles and brain. It also increases your blood sugar level by helping breakdown the sugar stored in the liver.
• Norepinephrine: Also known as noradrenaline, this hormone works with epinephrine in responding to stress. However, it can cause vasoconstriction (the narrowing of blood vessels). This results in increasing blood pressure in preparing the body to stress.

Disorders and Diseases of the Adrenal Glands

There are multiple reasons why the adrenal glands might not work as they should. The problem could be with the adrenal gland itself, or the root cause may be due to a defect in another gland.
Below are the most common disorders and diseases of the adrenal glands:
• Addison’s Disease: This rare disorder may affect anyone at any age. It develops when the adrenal cortex is destroyed and fails to produce enough cortisol and aldosterone.
• Cushing’s Syndrome: Cushing’s syndrome is an uncommon condition that is caused by overproduction of the hormone cortisol. There are a variety of causes of this disorder, a tumor in the adrenal gland or pituitary gland can lead to an overproduction of cortisol.
• Congenital Adrenal Hyperplasia: This genetic disorder is characterized by low levels of cortisol. It’s common for people with congenital adrenal hyperplasia to have additional hormone problems such as low levels of aldosterone (which maintains a balance of water and salt). In women, this disorder may present with abnormal menses or hirsutism.
• Adrenal Cancer: Adrenal cancer is an aggressive cancer, but it’s very rare. Malignant adrenal tumors are rarely confined to the adrenal glands and spread rapidly to other organs and produce high levels of adrenal hormones.


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Here’s How Thyroid Levels Affect Your Metabolism – And Your Health – Blog

What does the thyroid do? Your thyroid – a small gland that sits at the front of your neck – keeps your metabolism running smoothly. Because your thyroid controls so much of your metabolism, it must function properly for you to remain healthy and feeling good.

The thyroid gland regulates metabolism by releasing hormones into the bloodstream, so by measuring how much of these hormones you have and checking your thyroid function (do this at home with the Everlywell Thyroid Test), you may discover if there’s something wrong with your metabolism.

In many cases, people will experience thyroid weight gain or weight loss problems when there is an imbalance with their hormones due to a thyroid disorder. Our at-home testing options let you check your body’s metabolism hormones and thyroid function so you can learn if you have a hormonal imbalance.

The thyroid gland is quite a unique body part. For example, thyroid cells are the only cells in your body that can take up iodine – a rare element – in large amounts and build hormones with that iodine. These hormones are then released into the bloodstream. But when these hormones aren’t produced at a normal level, you may experience thyroid weight loss or weight gain—or other symptoms.

More specifically, the thyroid gland produces two hormones. These hormones are known as T3 and T4. Although the thyroid gland makes more T4, the T3 hormone is more potent. Most thyroid hormones bind to other molecules in your blood – and are thus inactive – but some of these hormones jostle about freely in your blood, and can thus get work done by themselves.

If the thyroid gland regulates your metabolism, then what is it that controls the thyroid gland itself? The answer to that is the pituitary gland. When the pituitary gland “senses” that your body’s thyroid hormone levels need to be adjusted, it sends a hormonal signal to the thyroid gland in the form of thyroid-stimulating hormone (known as “TSH”). So what does high TSH mean? Elevated TSH levels in your blood typically mean that your thyroid isn’t pumping out enough thyroid hormones.

There are also some molecules that suggest your thyroid gland isn’t functioning correctly. These molecules are called “thyroid peroxidase antibodies” – or TPOab. The presence of these thyroid antibodies points to the possibility of an autoimmune disorder that’s impairing your thyroid’s function.

Thyroid hormones are essential to your metabolism. In fact, many of your body’s cells have thyroid hormone receptors, which means that thyroid hormones can influence your metabolism in a host of ways.

Take fat metabolism, for example. Thyroid hormones help your body burn fat – providing you with more energy. As a result of this effect on fat metabolism, thyroid hormones bump up your basal metabolic rate (BMR) – which means you’ll be burning off fat even when you’re not physically active.

Thyroid hormones also impact carbohydrate metabolism. For instance, thyroid hormones stimulate the production of glucose (a sugar – which is produced when carbohydrates are broken down – that your body uses for energy). Your brain runs on glucose as its energy source, so if it weren’t for your thyroid hormones, your brain couldn’t function. The result would be a bit like unplugging your computer from its power source – or taking out its battery!

What’s more, thyroid hormones also control your body’s internal temperature, protecting your organs from frosty temperature in the winter or boiling-hot conditions during the summer. In women, thyroid hormones help maintain a regular menstrual cycle – just one more example of the large number of ways thyroid hormones regulate so many aspects of your body.

In short, to feel energized and be healthy, you need optimal thyroid levels. But there’s a catch: you have to have the right amounts of thyroid hormones. When your body doesn’t have the right levels of thyroid hormones, your health falters.


Iodine – frequently found in seawater and seafood – is essential to human health. And if you’re not getting enough iodine in your diet, then you may be putting your health through the gauntlet of hypothyroidism. Hypothyroidism refers to an underactive thyroid – your thyroid gland doesn’t produce enough thyroid hormones. Iodine deficiency may result in hypothyroidism TSH levels (high TSH), but this is not the only possible cause of low thyroid hormone levels. For example, autoimmune disorders – as well as exposure to radiation therapy during cancer treatment – can also lead to hypothyroidism.

Symptoms of low thyroid hormone levels range from the dramatic to the somewhat more subtle. People with hypothyroidism might gain weight rapidly, for example – or find themselves wearily running on fumes all day due to excessive fatigue. Hair loss can also result – and you may be less resistant to cold temperatures. Your skin can also have a cool and dry feel to it. In women, irregular – or even completely absent – menses is another sign of low thyroid hormone levels.


Perhaps you’ve been feeling lots of anxiety before an important job interview – and it just doesn’t seem to go away. Well, it could be more than just nerves, since high thyroid levels are known to heighten anxiety.

This is just one example of the consequences of high thyroid hormone levels. Other consequences? Swift weight loss, high blood pressure, and thinning hair – to name a few. When your thyroid hormone levels get too high, you can also experience tremors and an irregular heartbeat – and have a hard time concentrating or sleeping.

As you can see, high thyroid hormone levels can disrupt your health in many different ways – the frightening aftermath of a thyroid gland gone awry. Fortunately, medical researchers and scientists have discovered several different causes of hyperthyroidism (and other common thyroid problems). Autoimmune disorders – such as Graves’ disease – can lead to an overactive thyroid that pumps out too much thyroid hormones (and is associated with reduced levels of thyroid-stimulating hormone). A malfunctioning pituitary gland can likewise coax your thyroid gland into gushing out too much thyroid hormone. Dietary supplements intended for weight loss may also trigger hyperthyroidism TSH levels (low TSH). In some cases, a healthcare provider may prescribe thyroid medication to help rebalance hormone levels in the body.


Remember when we were talking about TSH levels? TSH is a hormone released by the pituitary gland that stimulates the thyroid gland to produce more thyroid hormones. If your TSH levels are too low, then you may have an overactive thyroid gland – with your body producing too much thyroid hormones, which can lead changes in your body’s metabolism. (A low TSH value could also mean that you’re taking too much thyroid hormone supplementation or medication.) And if you have high TSH levels, then the reverse is true: you may have an underactive thyroid gland that’s not producing enough hormones. (Related: Hypothyroidism vs. hyperthyroidism)


When TPO antibody (TPOab) levels are found in profuse amounts in your blood, it’s a red flag that your thyroid gland may be malfunctioning because of an autoimmune disorder. Not everyone with high TPOab levels has a badly-working thyroid gland, but elevated levels are commonly seen in individuals with autoimmune thyroid diseases, such as Hashimoto’s thyroiditis.


After all this thyroid-hormone-levels-gone-wrong talk, you’d be justified in thinking to yourself, “Okay, so how can I get healthy thyroid hormone levels to help avoid a thyroid problem?”

First, make sure you’re getting the right amount of iodine in your diet (your body can’t make iodine, so it’s got to come from the food you eat). (Related: Foods that help thyroid function)

For men and non-pregnant women, the recommended daily allowance for iodine is 150 micrograms (mcg). For pregnant women, that number rises to 220 mcg per day – and 290 mcg a day for women who are breastfeeding.

If you want to check if you have an underactive thyroid gland (perhaps because you’re experiencing signs of primary hypothyroidism)—or if you’re interested in finding out if you have high thyroid levels—getting a thyroid function test can be a good place to start.

Of course, if your thyroid hormone level isn’t within a normal range and you may have a thyroid dysfunction, consult with your healthcare provider to learn what solution is best for you to help get your hormone levels back in balance (in some cases, thyroid hormone replacement may be recommended). If you do have a thyroid disorder or thyroid condition, your healthcare provider may recommend ongoing thyroid testing to monitor results of your treatment plan.


Your thyroid gland is a key part of your metabolic health. The hormones released by the thyroid gland regulate your body’s functioning in a stunning variety of ways. But your well-being can slide downhill when your thyroid hormone levels are too high – or too low. If you’re experiencing changes in body weight, hair loss, lethargy, or other symptoms related to a thyroid condition, thyroid function tests can help you check your levels of thyroid hormones to see if they are abnormal.

Testing your thyroid hormone levels with the Everlywell at-home Thyroid Test is an easy, effective way to check on the status of your thyroid—from the comfort of your home. And our at-home Thyroid Test is more than just a TSH test: it measures TSH in addition to the thyroid hormones T3 and T4 (plus TPOab)—giving you a comprehensive, easy way to see if you might have too much or not enough thyroid hormones in your body.

Endocrine glands

Biologically active substances – hormones – are of great importance in the life of humans and animals. They are produced by special glands, which are richly supplied with blood vessels. These glands do not have excretory ducts, and their hormones enter directly into the bloodstream, and then are carried throughout the body, carrying out humoral regulation of all functions: they excite or inhibit the activity of the body, affect its growth and development, and change the intensity of metabolism.Due to the absence of excretory ducts, these glands are called endocrine glands, or endocrine glands, in contrast to the digestive, sweat, sebaceous glands external secretion, having excretory ducts.

In terms of structure and physiological action, hormones are specific: each hormone has a powerful effect on certain metabolic processes or the work of an organ, causing a slowdown or, conversely, an increase in its function. The endocrine glands include the pituitary gland, the thyroid gland, the parathyroid glands, the adrenal glands, the insular part of the pancreas, and the intrasecretory part of the gonads.All of them are functionally interconnected: hormones produced by some glands affect the activity of other glands, which provides a single coordination system between them, which is carried out according to the feedback principle. The dominant role in this system belongs to the pituitary gland, whose hormones stimulate the activity of other endocrine glands.

The pituitary gland is one of the central endocrine glands, located under the base of the brain and has a mass of 0.5-0.7 g.The pituitary gland consists of three lobes: anterior, middle and posterior, surrounded by a common capsule of connective tissue. One of the hormones in the anterior lobe affects growth. An excess of this hormone at a young age is accompanied by a sharp increase in growth – gigantism, and with an increased function of the pituitary gland in an adult, when body growth stops, an increased growth of short bones occurs: the tarsus, metatarsus, phalanges of the fingers, as well as soft tissues (tongue, nose) … This disease is called acromegaly. Decreased function of the anterior pituitary gland leads to dwarf growth. Pituitary dwarfs are proportionally built and normally mentally developed. In the anterior lobe of the pituitary gland, hormones are also formed that affect the metabolism of fats, proteins, carbohydrates. In the posterior lobe of the pituitary gland, an antidiuretic hormone is produced, which reduces the rate of urine formation and changes water exchange in the body.

The thyroid gland is located in the anterior region of the neck, weighs 30-60 g and consists of two lobes connected by an isthmus. Inside the gland there are small cavities, or follicles, filled with a mucous substance containing thyroxine hormone. The hormone contains iodine. This hormone affects the metabolism, especially fat, the growth and development of the body, increases the excitability of the nervous system, the activity of the heart. With the proliferation of thyroid tissue, the amount of hormone entering the blood increases, which leads to a disease called Graves disease. The patient’s metabolism increases, which is expressed in severe emaciation, increased excitability of the nervous system, increased sweating, rapid fatigue, and bulging.

With reduced thyroid function, the disease myxedema occurs, manifested in mucous edema of tissues, slowing down of metabolism, delayed growth and development, memory impairment, mental impairment. If this happens in early childhood, cretinism (dementia) develops, characterized by mental retardation, underdevelopment of the genitals, dwarf growth, and disproportionate body structure. In mountainous areas, there is a disease known as endemic goiter, arising from a lack of iodine in drinking water.At the same time, the tissue of the gland, growing, for some time compensates for the deficiency of the hormone, but in this case it may not be enough for the body. In order to prevent endemic goiter, the inhabitants of the corresponding zones are supplied with iodine-enriched table salt or added to the water.

Adrenal glands – paired glands located at the upper edge of the kidneys. Their weight is about 12 g each, together with the kidneys they are covered with a fat capsule. They distinguish between cortical, lighter substance, and cerebral, dark.In the cortical layer, several hormones are produced – corticosteroids, affecting salt and carbohydrate metabolism, promoting the deposition of glycogen in liver cells and maintaining a constant concentration of glucose in the blood. With insufficient function of the cortical layer, Addison’s disease develops, accompanied by muscle weakness, shortness of breath, loss of appetite, a decrease in the concentration of sugar in the blood, and a decrease in body temperature. At the same time, the skin acquires a bronze tint – a characteristic sign of this disease.In the adrenal medulla, the hormone adrenaline is produced. Its action is manifold: it increases the frequency and strength of heart contractions, increases blood pressure (while the lumen of many small arteries narrows, and the arteries of the brain, heart and renal glomeruli expand), enhances metabolism, especially carbohydrates, accelerates the conversion of glycogen (liver and working muscles) into glucose, as a result of which muscle performance is restored.

The pancreas functions as a mixed gland, the hormone of which – insulin – is produced by the cells of the islets of Langerhans.Insulin regulates carbohydrate metabolism, that is, it promotes the absorption of glucose by cells, maintains its constancy in the blood, converting glucose into glycogen, which is deposited in the liver and muscles. The second hormone of this gland is glucagon. Its action is opposite to insulin: with a lack of glucose in the blood, glucagon promotes the conversion of glycogen into glucose. With a reduced function of the islets of Langerhans, the metabolism of carbohydrates, and then proteins and fats, is disturbed. The content of glucose in the blood increases from 0.1 to 0.4%, it appears in the urine, and the amount of urine increases to 8-10 liters.This disease is called diabetes mellitus . It is treated by administering insulin extracted from animal organs to humans.

The activity of all endocrine glands is interrelated: the hormones of the anterior pituitary gland contribute to the development of the adrenal cortex, increase the secretion of insulin, affect the entry of thyroxine into the blood and the function of the gonads. The work of all endocrine glands is regulated by the central nervous system, which contains a number of centers associated with the function of the glands.In turn, hormones affect the activity of the nervous system. Disruption of the interaction of these two systems is accompanied by serious disorders of the functions of organs and the body as a whole.

90,000 How light and darkness control our biological rhythms – Rossiyskaya Gazeta

For some reason, domestic cats ask for food from early morning, and office workers wake up hungry in the afternoon. Owls get food at night, and many residents of St. Petersburg dislike white nights because of insomnia. A biological clock is ticking in each of us, but what processes are hidden behind the movement of their hands?

Where the clock is hidden

The biological clock is one of the body’s systems, like the immune system or the cardiovascular system.All living beings need this clock in order to synchronize with the rhythms of nature – to adapt to the change of day and night or the change of seasons. Many body functions obey the biological clock, including heat regulation, blood pressure, and hormone production.

The clock that controls our body operates on three levels. The first is a tiny clockwork hidden in every cell. For its discovery, American researchers Jeffrey Hall, Michael Rosbash and Michael Young received the 2017 Nobel Prize in Physiology or Medicine.

The main role in it is played by special lock-proteins, which are synthesized in all cells with a nucleus – in animals, plants and fungi. Some of the lock proteins are formed in the morning, activating the metabolism in the cell, the other – in the evening, inhibiting the metabolism. This is how the daily, or circadian (from the Latin circa – about and dies – day), rhythm of the work of an individual cell is set. And if any of the genes that synthesize lock proteins mutate, various rhythms of the body can be disrupted: sleep and wakefulness, motor activity, digestion.All these rhythms are connected – if a person does not sleep at night, this can lead not only to insomnia or depression, but also to diabetes, even to cancer.

A clock is needed not only for every cell, but also for the body as a whole. The rhythms of all cells are synchronized by a special hormonal gland of the brain called the pineal gland, or pineal gland, which produces melatonin and serotonin – hormones that regulate our sleep and wakefulness, as well as appetite and mood. During the daytime, the pineal gland produces the “happiness hormone” serotonin, and in the dark, serotonin is converted into the “sleep hormone” melatonin – it makes sleep deeper and more fulfilling.

A sufficient amount of melatonin is produced only in the dark, even dim light will reduce its production – turn off all lamps and curtain windows! And serotonin, on the contrary, needs light: the more light, the better the mood and the higher the efficiency.

Now let’s move on to the third level. The suprachiasmatic nuclei of the hypothalamus are the highest control center for all rhythmic functions of the body. It is to this group of nerve cells that a direct signal from the retina of the eye comes, which tells the clock what is now on the street: day or night. This small area in the diencephalon is the main generator of circadian rhythms, its neurons adjust to external light signals and control the pineal gland.

All in good time

02:00 – Deepest sleep

03:00 – Lowest blood pressure

04:30 – Lowest body temperature

06:45 – Sharpest increase in blood pressure

07:30 – Melatonin secretion ceases

08:30 – Possible urge to defecate

10:00 – Highest readiness for action

14:30 – Maximum coordination

15:30 – Fastest reaction time

17:00 – Most active blood circulation and maximum muscle strength

18:30 – Highest blood pressure

19:00 – Highest body temperature

21:00 – Melatonin secretion begins

22:30 – Intestinal motility is suppressed

Source of this ” schedules “- the book” Biohacking.A guide to unlocking the full potential of the body “by Finnish researchers Sovijärvi Olli, Teemu Arina and Halmetoya Jaakko. But the time is indicated here approximately – do not be discouraged if you have” the highest readiness for action “comes much later than ten in the morning!

How not to break your watch

And what about owls and larks – their clocks are set differently? In fact, we don’t know. Maybe there are also “pigeons” – people who are active during the day, but sleepy in the morning and evening. no matter what bird you are, you need to sleep at night and stay awake during the day.This is how we are genetically programmed, to live differently means to shorten life.

It is especially harmful to constantly change your routine. For example, researchers at the University of Michigan looked at the Nurses Health Study database – a long-term study of the health of more than 120,000 American nurses – and found that shift work (either day or night) increases the risk of ischemic stroke by 4% every five years. Other studies based on the same data have shown that working a night shift at least three nights a month for 15 years or more may increase the risk of colorectal cancer as well as breast cancer.

The reason is desynchronosis, that is, an imbalance in biological rhythms, which is a risk factor for the development of cardiovascular and oncological diseases. Desynchronosis is accompanied by prolonged increased fatigue, decreased performance and sleep disturbances.

One-time desynchronosis is known to everyone who has experienced jetlag – a syndrome that occurs when the time zone changes abruptly when a person crosses more than three or four time zones. After it comes the stage of resynchronization – when the biological rhythms of the body adjust to new conditions.Interestingly, if the flight was from east to west, the average recovery rate will be 92 minutes per day, and if from west to east, it will be one and a half times lower, 57 minutes per day. It turns out that it is more difficult to adapt when flying to the east.

Our body also feels out of sync when we pass the time with a smartphone. It is the blue, short-wavelength part of the color spectrum that suppresses the production of melatonin. The photopigment melanopsin in the cells of the retina reacts to blue light – the opinion of the brain about whether it is night or day now depends on it.In the red light, the brain does not understand that it is day outside. But the screens of gadgets just emit a bright and cold blue light, in vain invigorating the brain in the middle of the night.

Biohackers: mobile apps for taking care of circadian rhythms

What is called: My circadian clock

What it works on: Android and IOS

What can: helps to normalize the rhythms of sleep, food and physical activity

How it works. The course of the biological clock depends not only on light, but also on the time of training and food intake.Moreover, the more predictable the daily routine, the more successful biorhythms will regulate important processes in the body: digestion, immune response, sleep and much more. You can use the mobile app to see your schedule in the form of graphs, get recommendations, and help scientists at the Salk Institute for Biological Research in the United States to learn more about the circadian rhythms of different people. For the first two weeks, it will carefully collect information about the subject, and then it will begin to instill good habits – for example, not skipping lunch at work and going to bed on time.

How it is called: Twilight

What it works on: Android

What it can do: prevents gadgets from spoiling sleep

How it works. From a medical point of view, life with rose-colored glasses can be quite rewarding. But it is even better to build a red or orange filter between the eyes and the screens of the gadgets. It is useful to observe such a regime in the evenings, so that the blue spectrum does not once again lead to the production of melanopsin, which signals the biological clock that it is day now – time to be awake.A mobile application will help reduce the harmful effects of blue screens, which will make the display colors warmer with the onset of the evening. By the way, in many modern smartphones this function is included in the standard settings.

As it is called: Lux Light Meter Free

What it works on: Android

What it can do: measures the level of illumination

How it works. If you go on a safari to some African country, the retina of the eye will receive at least 1000 lux every day (these are the units in which the level of illumination is measured).But in an office space with the lights on, the indicators will be completely different – about 500 lux if the employee sits near the window without curtains. And since the amount of light affects not only the mode of sleep and wakefulness, but also our mood, it would be nice to know how well the rooms in which we spend a lot of time are illuminated. The most accurate result will be given by a luxmeter, but you can also use a mobile device with a light sensor and an appropriate application. The main rule is to try to get suites in the morning and afternoon, but avoid bright lights in the evening and at night.

Glands and hormones. Biology, Human (grade 8): lessons, tests, assignments.

1. Match the glands with their characteristics



2. Glands and hormones

the average


3. Determine the type of gland from the drawing



4. Are the statements correct?

the average


5. Identify the hormone-producing gland from the drawing and give it a name



6. Endocrine glands and their hormones



7. Pancreas



eight. Hormones



nine. Find mistakes in the text of “Glands”

the average


Treatment of disorders of phosphorus-calcium metabolism – MEDSI

Hypercalcemia syndrome (increased calcium in the blood) can manifest itself with a variety of nonspecific clinical symptoms, the severity of which depends on the level of calcium in the blood:

  • General weakness
  • Decreased concentration of attention
  • Dry skin and mucous membranes
  • Thirst
  • Nausea, vomiting
  • Decreased appetite and weight
  • Constipation
  • Arterial hypertension
  • Cardiac arrhythmias

The manifestations of osteoporosis are fractures with minor injuries, bone pain, muscle weakness, stiffness of movements, convulsions.

The syndrome of hypocalcemia (a decrease in calcium in the blood) is characteristic of a decreased function of the parathyroid glands (hypoparathyroidism), which develops most often after surgical removal or impaired blood supply to the parathyroid glands (after operations on the thyroid gland).

Symptoms of hypocalcemia include:

  • Muscle cramps
  • Paresthesias (creeping sensations)
  • Dry skin
  • Brittleness of hair, nails
  • Cardiac arrhythmias

Risk groups for the development of calcium metabolic disorders

Disorders of calcium metabolism occur not only in patients with endocrine pathologies, which are accompanied by increased bone resorption (patients with hyper- or hypoparathyroidism, Itsenko-Cushing’s disease, thyrotoxicosis, pheochromocytoma).

The risk group also includes:

  • Patients with osteopenia or osteoporosis
  • Patients with urolithiasis, chronic kidney disease, including those on programmed hemodialysis
  • Patients with recurrent erosive and ulcerative lesions of the upper gastrointestinal tract, malabsorption syndrome
  • Patients with relatives with parathyroid disease
  • Patients with cardiac arrhythmias
  • Patients with disorders of carbohydrate metabolism (obesity, type 2 diabetes mellitus)

Patients included in these risk groups for the development of calcium metabolic disorders are assigned to determine the level of serum calcium and parathyroid hormone in the blood.

Pathology of the endocrine system – StudIzba

Lecture No. 11

Topic: Pathology of the endocrine system.

1) Dysfunction of the pituitary gland.

2) Adrenal dysfunction.

3) Thyroid dysfunction.

4) Dysfunction of the parathyroid glands.

5) Pancreatic dysfunction.

6) Dysfunction of the sex glands.

Recommended files

Endocrine regulation is carried out by endocrine glands, which produce specific biologically active substances – hormones.

The activity of the endocrine glands is disrupted when exposed to both endo – and exogenous stimuli.

There are the following forms of endocrine disorders:

    1. Hyperfunction – increased activity;
    2. Hypofunction – decrease in activity;
    3. Dysfunction – perversion of activity (combination of hyper – and hypofunction).
  1. Pituitary dysfunction.

The pituitary gland is the main endocrine gland in the body, which regulates the activity of other endocrine glands through the production of so-called tropic hormones.

In case of pituitary pathology, the function of other endocrine glands and metabolism in general are disrupted.

A) Pituitary hyperfunction.

An excess of adrenocorticotropic hormone (ACTH) leads to an increase in the function of the adrenal cortex, which causes overproduction of corticosteroids and changes in metabolism.

An excess of thyroid-stimulating hormone (TSH) causes an overproduction of thyroxine, which leads to hyperthyroidism and thyrotoxicosis.

An excess of growth hormone (STH) is accompanied by acromegaly or pituitary gigantism.

Acromigaly – disproportionate development of the body in combination with impaired metabolism.

Gigantism – small head and long limbs.

B) Pituitary hypofunction.

A decrease in the production of STH leads to a delay in the growth and development of the animal. Hypophysis of the pituitary gland is manifested by diabetes insipidus. With severe damage to the pituitary gland (tumor, tuberculosis), pituitary cachexia occurs. This is a sharp exhaustion combined with atrophy of the bone and reproductive apparatus, hair and teeth loss. At a young age, the pituitary gland causes dwarfism. Unlike the thyroid dwarf, the pituitary dwarf has the correct body proportions and does not lag behind in mental development.

  1. Adrenal dysfunction.

Two layers are distinguished in the adrenal glands: cortical and medullary.

The medulla produces two hormones: adrenaline and norepinephrine. These hormones affect the body in a similar way to the sympathetic nervous system. The cortex produces corticoids and corticosteroids. These hormones regulate water – salt metabolism, inflammation, allergic reactions and affect the sexual sphere.

Adrenal hyperfunction is accompanied by Itsenko – Cushing’s syndrome (violation of protein, fat, water – salt metabolism and the function of the cardiovascular system).

With the overproduction of sex hormones, two types of disorders occur:

1) Excessive production of hormones of the same sex;

2) Excess hormones of the opposite sex.

3. Thyroid dysfunction.

A specific component of the thyroid gland – iodine – is contained in it in the form of organic and inorganic compounds. Thyroid hormones (diiodothyronine, triiodothyranine, tetraiodothyranine (thyroxine), thyrocalciotonin) affect metabolism, growth and development of the body, and the state of the nervous system.

A) Thyroid hypofunction.

As a physiological phenomenon – during hibernation, at high ambient temperatures.

Pathologically – with a lack of iodine in the feed, with the defeat of the gland by a tumor, its inflammation, with pathology of the pituitary gland, with an excess of antithyroid substances (fluorine, sulfonamides).

In hypothyroidism, metabolism decreases, electrolyte metabolism is disturbed, regeneration slows down, and immunity decreases. Young animals often develop myxedema . This is a serious disease characterized by edema of the subcutaneous tissue, metabolic disorders and decreased mental abilities. In adult animals, the so-called endemic goiter is formed. This is an enlargement of the thyroid gland due to the proliferation of its connective tissue and the accumulation of colloid in the follicles of the thyroid gland. At the same time, hormones are practically not released.

Endemic goiter is common in the so-called biogeochemical provinces. Most often these are mountainous areas. Most common in dogs, sheep and goats.Signs: short stature, decreased productivity, frequent abortions, the offspring is not viable.

In children, hypothyroidism is accompanied by cretinism.

B) Thyroid hyperfunction.

Reasons: violation of its nervous regulation, hyperfunction of the pituitary gland, infections and intoxication, tumors of the thyroid gland. Hyperthyroidism is accompanied by metabolic disorders, cachexia, dysfunction of the central nervous system and other organs.

The most common form of hyperthyroidism is Graves’ disease.More common in dogs.

The disease is characterized by three characteristic manifestations:

  1. Goiter – an increase in the volume of the thyroid gland;
  2. Tachycardia;
  3. Exophthalmos (bulging eyes).

An increase in the volume of the gland occurs from hyperemia of the gland and hyperplasia of its follicular apparatus. The release of excess hormones into the bloodstream causes thyrotoxicosis. Tachycardia occurs due to the excitation of sympathetic nerves by hormones that innervate the heart. Exophthalmos is caused by overstimulation of the sympathetic nerve of the eyeball.This causes a sharp increase in the tone of the smooth muscle behind the eyeball.

  1. Dysfunction of the parathyroid (parathyroid) glands.

A) Hyperparathyroidism.

Causes: adenoma (tumors of the parathyroid glands), decreased calcium levels.

Strengthening of function is accompanied by glandular hyperplasia.

Pathogenesis: under the influence of parathyroid hormone, the activity of osteoclasts increases in comparison with osteoblasts.This leads to the development of fibrous osteodystrophy. In this case, calcium leaves the bone tissue into the blood and further into the urine.

B) Hypoparathyroidism can be induced artificially by removing the parathyroid glands. Convulsions and disruption of the activity of all systems occur.

  1. Pancreatic dysfunction.

Two parts are functionally distinguished in the pancreas: digestive and hormonal. The hormonal one is represented by the islet apparatus (this is how the islets of Langerhans are called).Islet cells produce insulin and glucagon, which regulate blood sugar levels. In addition, the pancreas produces the hormone lipocaine, which regulates fat metabolism in the liver, preventing fatty infiltration of this organ.

Diabetes mellitus (diabetes mellitus) develops in the pathology of the pancreas. In this case, all types of metabolism are disrupted, especially carbohydrate and fat. Hyperglycemia, glucosuria appear, glycogen stores disappear in the liver.

The function of the pancreas also decreases with hyperfunction of other endocrine glands.

  1. Dysfunction of the sex glands.

1) Pathology of the male reproductive glands (testicles).

Male sex hormones produced in the testes (the main one is testosterone) stimulate the development of the reproductive apparatus and secondary sexual characteristics in males, the appearance of sexual reflexes and affect metabolism.

A) Male hypogonadism.

Causes: trauma, testicular pathology, hypofunction of the pituitary gland.The function of the testes is inhibited, sexual activity and sperm production are reduced.

B) Hypergonadism in males.

Causes: testicular tumors, pituitary hyperfunction.

During the period (before puberty), the genital organs of sexual desire develop prematurely. Growth at first sharply increases, and then inhibited due to premature ossification of the skeleton. It turns out dwarf males.

In adult animals, excessive libido simply develops.

B) Cryptorchidism.

This is the undescended testes through the inguinal canal into the scrotum. They remain in the abdominal cavity or in the inguinal canal.

Reason : hormonal imbalance in pregnant women.

There is one- and two-sided cryptorchidism. With bilateral, there will always be infertility due to the loss of spermogenic function. The reasons are mechanical compression and temperature factor.

2) Pathology of the female reproductive glands (ovaries).

In the ovaries, hormones are produced in the follicles and the corpus luteum. Folliculin (estradiol) is formed in the follicles. It stimulates estrus, the development of the reproductive apparatus and secondary sexual characteristics. In the corpus luteum, progesterone (pregnancy hormone) is produced. It delays the maturation of new eggs, causes hypertrophy of the uterus and mammary glands.

A) Female hypogonadism.

Causes : ovarian pathology, lack of gonadotropins.

With hypofunction of the follicular apparatus, underdevelopment of the genitals and secondary sexual characteristics occurs, cessation of estrus and infertility.

Loss of yellow thallus function in the first third of pregnancy leads to abortion or intrauterine resorption of the fetus. If the corpus luteum does not undergo involution and continues to function, estrus is delayed and further infertility occurs.

There is also a lot of useful information in the “Contents” lecture.

B) Hypergonadism of females.


1) Hyperfunction of the adenohypophysis as a result of brain pathology (dropsy, meningitis, trauma, etc.). This increases the amount of gonadotropins.

2) Tumors of the adrenal glands (the amount of estrogen increases).