What is the thyroid gland and where is it located. How does the thyroid gland function within the endocrine system. What are the main thyroid hormones and their effects on the body. How does the thyroid gland regulate metabolism. What are common thyroid disorders and their symptoms. How are thyroid conditions diagnosed and treated. What is the relationship between the thyroid and other endocrine glands.

The Thyroid Gland: An Essential Component of the Endocrine System

The thyroid gland is a crucial organ within the human endocrine system, working in concert with the nervous and immune systems to regulate the body’s metabolism. This butterfly-shaped gland is located in the lower front part of the neck, just below the Adam’s apple, and consists of two lobes on either side of the windpipe.

The primary function of the thyroid gland is to produce and secrete hormones into the bloodstream, which play a vital role in controlling various bodily functions. These hormones are essential for maintaining proper metabolism, which encompasses all the processes occurring within the body, including the conversion of food into energy.

Key Thyroid Hormones

The thyroid gland produces two main hormones:

• Thyroxine (T4)
• Triiodothyronine (T3)

These hormones are responsible for regulating numerous bodily functions, including:

1. Body temperature and circulation
2. Appetite
3. Energy levels
4. Growth and bone development
5. Muscle tone and suppleness
6. Heart rate
7. Blood sugar levels
8. Central nervous system and bowel function
9. Cholesterol levels
10. Fat, carbohydrate, and protein metabolism

The Intricate Relationship Between Thyroid Hormones and Metabolism

The thyroid gland plays a pivotal role in controlling the chemical metabolic processes continuously occurring within the body. This metabolic regulation is crucial for providing the energy necessary for survival and optimal functioning.

Iodine is an essential component in the production of thyroid hormones. Most individuals obtain sufficient iodine from their diet, primarily through seafood consumption. Vegetables grown in iodine-rich soils also contribute to dietary iodine intake.

The Impact of Thyroid Hormone Levels on Metabolism

The concentration of T3 and T4 hormones circulating in the bloodstream directly affects the speed of metabolism. Higher levels of these hormones result in a faster metabolism, while lower levels lead to a slower metabolic rate.

When the thyroid gland becomes overactive (hyperthyroidism) or underactive (hypothyroidism), it disrupts normal functioning and triggers abnormal chemical reactions in the body. These imbalances can lead to:

• Disruption of the entire metabolic system
• Unusually high or low levels of hormones or enzymes
• Malfunctioning hormones or enzymes
• Accumulation of toxic substances in the body
• Development of diseases and serious health conditions

The Pituitary-Thyroid Axis: A Delicate Balance

The pituitary gland, located at the base of the brain, plays a crucial role in regulating thyroid function. It produces thyroid-stimulating hormone (TSH), which stimulates the thyroid gland to produce T3 and T4 hormones.

This relationship operates on a feedback loop: when T4 levels in the bloodstream are high, the pituitary reduces TSH production, slowing thyroid activity. Conversely, when T4 levels are low, the pituitary increases TSH production to stimulate the thyroid and boost hormone production.

The Significance of TSH in Thyroid Function

TSH levels serve as a valuable indicator of thyroid health. Elevated TSH levels often suggest an underactive thyroid, while low TSH levels may indicate an overactive thyroid. This delicate balance is crucial for maintaining proper metabolic function throughout the body.

Goiter: A Visible Sign of Thyroid Dysfunction

A goiter is an abnormal enlargement of the thyroid gland, often visible as a swelling in the neck. This condition can occur due to various factors, with iodine deficiency being a common cause in some regions.

When the body lacks sufficient iodine, the pituitary gland may attempt to compensate by overstimulating the thyroid to produce more hormones. This increased stimulation can cause the thyroid to grow larger, resulting in a goiter.

Implications of Goiter

The presence of a goiter suggests that the thyroid is not functioning properly or that there is an underlying iodine deficiency. While not all goiters are harmful, they can sometimes interfere with breathing or swallowing and may require medical attention.

Common Thyroid Disorders: Understanding the Spectrum

Several disorders can affect the thyroid gland, impacting its function and overall health. Some of the most common thyroid-related conditions include:

• Graves’ disease
• Hashimoto’s disease
• Thyroid cancer
• Thyroid nodules
• Congenital thyroid disease
• Iodine deficiency disorder

Hyperthyroidism: When the Thyroid Goes into Overdrive

Hyperthyroidism is a condition characterized by an overactive thyroid gland that produces excessive amounts of T3 and T4 hormones. This hormonal imbalance leads to an accelerated metabolism, causing various symptoms throughout the body.

The most common cause of hyperthyroidism is Graves’ disease, an autoimmune disorder where the immune system mistakenly attacks the thyroid gland, stimulating it to produce excess hormones.

Symptoms of Hyperthyroidism

• Rapid heartbeat
• Unexplained weight loss
• Increased appetite
• Nervousness and anxiety
• Tremors in hands and fingers
• Excessive sweating
• Changes in menstrual patterns
• Increased sensitivity to heat
• Enlargement of the thyroid gland (goiter)

Hypothyroidism: When the Thyroid Slows Down

Hypothyroidism occurs when the thyroid gland is underactive and produces insufficient amounts of T3 and T4 hormones. This deficiency results in a slowed metabolism and can affect various bodily functions.

The most prevalent cause of hypothyroidism is Hashimoto’s disease, an autoimmune condition where the immune system attacks and damages the thyroid gland, impairing its ability to produce hormones.

Symptoms of Hypothyroidism

• Fatigue and weakness
• Unexplained weight gain
• Increased sensitivity to cold
• Dry skin and hair
• Depression
• Constipation
• Muscle aches and stiffness
• Joint pain and swelling
• Irregular or heavy menstrual periods
• Slowed heart rate

Diagnosis and Treatment of Thyroid Disorders

Accurate diagnosis of thyroid disorders is crucial for effective treatment. Healthcare providers employ various methods to assess thyroid function and identify underlying issues.

Diagnostic Tools for Thyroid Disorders

1. Blood tests: Measuring levels of TSH, T3, and T4 hormones
2. Thyroid ultrasound: Imaging the gland to detect nodules or structural abnormalities
3. Radioactive iodine uptake test: Assessing how much iodine the thyroid absorbs
4. Thyroid scan: Creating detailed images of the thyroid gland
5. Fine-needle aspiration biopsy: Examining thyroid tissue for cancer or other abnormalities

Treatment Options for Thyroid Disorders

Treatment approaches for thyroid disorders vary depending on the specific condition and its severity. Common treatment options include:

• Medication: Synthetic thyroid hormones for hypothyroidism or anti-thyroid drugs for hyperthyroidism
• Radioactive iodine therapy: Destroying overactive thyroid cells in cases of hyperthyroidism
• Surgery: Removing part or all of the thyroid gland in cases of cancer or large goiters
• Lifestyle modifications: Dietary changes, stress management, and regular exercise
• Alternative therapies: Complementary approaches such as acupuncture or herbal supplements (under medical supervision)

The Thyroid’s Influence on Overall Health and Well-being

The thyroid gland’s impact extends far beyond metabolism, affecting numerous aspects of physical and mental health. Understanding the wide-ranging effects of thyroid function can help individuals recognize potential issues and seek appropriate care.

Thyroid Health and Cardiovascular Function

Thyroid hormones play a crucial role in maintaining cardiovascular health. They influence heart rate, blood pressure, and cholesterol levels. Both hyperthyroidism and hypothyroidism can lead to cardiovascular complications if left untreated.

Thyroid Disorders and Mental Health

The thyroid’s influence on mental health is significant. Hypothyroidism can contribute to depression and cognitive difficulties, while hyperthyroidism may lead to anxiety and mood swings. Proper thyroid function is essential for maintaining emotional well-being and cognitive clarity.

Thyroid Function and Reproductive Health

Thyroid disorders can have a substantial impact on reproductive health in both men and women. They may affect fertility, menstrual cycles, and pregnancy outcomes. Maintaining optimal thyroid function is crucial for those planning to conceive or during pregnancy.

Lifestyle Factors Affecting Thyroid Health

While some thyroid disorders have genetic or autoimmune origins, lifestyle factors can also influence thyroid function. Understanding these factors can help individuals maintain optimal thyroid health.

Nutrition and Thyroid Function

A balanced diet rich in essential nutrients is crucial for thyroid health. Key nutrients that support thyroid function include:

• Iodine: Essential for thyroid hormone production
• Selenium: Supports thyroid hormone metabolism
• Zinc: Aids in thyroid hormone synthesis
• Vitamin D: Helps regulate thyroid function
• Omega-3 fatty acids: May help reduce inflammation associated with autoimmune thyroid disorders

Stress Management and Thyroid Health

Chronic stress can negatively impact thyroid function by affecting the hypothalamic-pituitary-thyroid (HPT) axis. Implementing stress-reduction techniques such as meditation, yoga, or regular exercise can help support overall thyroid health.

Environmental Factors and Thyroid Function

Exposure to certain environmental toxins and chemicals can disrupt thyroid function. These include:

• Perchlorate: Found in some drinking water and foods
• Polychlorinated biphenyls (PCBs): Industrial chemicals that can accumulate in the environment
• Bisphenol A (BPA): Found in some plastics and food packaging
• Heavy metals: Such as mercury and lead

Minimizing exposure to these substances and supporting the body’s natural detoxification processes can help maintain thyroid health.

The Future of Thyroid Research and Treatment

As our understanding of thyroid function and disorders continues to evolve, new avenues for research and treatment are emerging. These advancements hold promise for improving the lives of those affected by thyroid disorders.

Precision Medicine in Thyroid Care

The field of precision medicine is advancing rapidly, offering the potential for more personalized approaches to thyroid disorder diagnosis and treatment. Genetic testing and biomarker analysis may help identify individuals at risk for thyroid disorders before symptoms appear, enabling earlier intervention and better outcomes.

Innovative Treatment Approaches

Researchers are exploring new treatment modalities for thyroid disorders, including:

• Targeted therapies for thyroid cancer
• Immunomodulatory treatments for autoimmune thyroid disorders
• Nanotechnology-based drug delivery systems for more effective hormone replacement
• Stem cell therapies for regenerating thyroid tissue

Integrative Approaches to Thyroid Health

There is growing interest in integrative approaches that combine conventional medical treatments with complementary therapies. These holistic strategies aim to address not only the thyroid disorder itself but also its impacts on overall health and well-being.

As research in these areas progresses, individuals with thyroid disorders may have access to more effective and personalized treatment options, improving their quality of life and long-term health outcomes.

Thyroid Health Awareness: Empowering Individuals

Increasing awareness about thyroid health is crucial for early detection and effective management of thyroid disorders. By understanding the signs and symptoms of thyroid dysfunction, individuals can take proactive steps to maintain their thyroid health and seek timely medical attention when needed.

Self-Monitoring for Thyroid Health

While professional medical evaluation is essential for diagnosing thyroid disorders, individuals can be alert to potential signs of thyroid dysfunction. Some self-monitoring techniques include:

• Regularly checking for visible enlargement or lumps in the neck area
• Being aware of unexplained changes in weight, energy levels, or mood
• Monitoring heart rate and body temperature for significant fluctuations
• Paying attention to changes in hair, skin, and nail health

When to Seek Medical Attention

Individuals should consult a healthcare provider if they experience persistent symptoms that may indicate a thyroid disorder, such as:

• Unexplained weight changes
• Persistent fatigue or changes in energy levels
• Mood disturbances or cognitive difficulties
• Irregular heartbeat or palpitations
• Changes in menstrual patterns or fertility issues
• Swelling or discomfort in the neck area

The Importance of Regular Check-ups

Regular medical check-ups that include thyroid function tests are essential, especially for individuals with a family history of thyroid disorders or those at higher risk due to factors such as age or gender. Early detection and treatment of thyroid issues can prevent complications and improve overall health outcomes.

By staying informed about thyroid health and working closely with healthcare providers, individuals can take an active role in maintaining optimal thyroid function and overall well-being. As research continues to advance our understanding of thyroid disorders, the future holds promise for even more effective prevention, diagnosis, and treatment strategies.

The thyroid gland

What is the thyroid gland?

The thyroid gland is a key part of the human endocrine system and works together with your nervous and immune systems to regulate your body’s metabolism.

Metabolism refers to all of the processes that go on inside your body, for example, the process of turning food into energy.

The thyroid gland regulates metabolism by producing and secreting hormones into your bloodstream.

Terms explained

Autoimmune disorder – a condition where your own antibodies attack your body.

Where is the thyroid gland?

The thyroid gland is located in the lower front part of your throat, just below your Adam’s apple. It consists of 2 lobes on either side of your windpipe.

What does the thyroid gland do?

Your thyroid produces 2 important hormones:

• Thyroxine, known as T4
• tri-iodothyronine, known as T3.

Thyroid hormones affect your:

• body temperature and circulation
• appetite
• energy levels
• growth and bone development
• muscle tone and suppleness
• heart rate
• blood sugar levels
• central nervous system and bowel function
• cholesterol levels
• fat, carbohydrate and protein metabolism.

Thyroid hormones and metabolism

Your thyroid controls the chemical metabolic processes constantly taking place inside your body. This process of metabolism is how your body gets the energy it needs to survive and has a vital function.

Your body needs iodine to make thyroid hormones. Most people get suitable amounts of iodine from their diet as it is found in most food, especially seafood. Small amounts of iodine are found in vegetables grown in soils containing iodine.

If your thyroid cannot produce a sufficient amount of hormones you are vulnerable to a range of serious health conditions.

The higher the T3 and T4 iodine count that circulates in your blood the faster your metabolism is. If you have less T3 and T4, your metabolism levels drop.

If your thyroid becomes overactive (hyperthyroidism), or underactive (hypothyroidism) it is not performing normally and starts to produce abnormal chemical reactions in your body leading to:

• disruption of your entire metabolic system
• unusually high or low levels of hormones or enzymes
• malfunctioning hormones or enzymes
• a build-up of toxic substances in your body
• diseases and serious health conditions.

Your pituitary and thyroid glands

The pituitary is an endocrine gland located at the base of your brain that controls your endocrine system, including your thyroid. The pituitary affects the thyroid by producing a hormone called thyroid stimulating hormone (TSH).

TSH causes cells within your thyroid to make more T3 and T4 hormone.

If there is too much T4 in your bloodstream your pituitary produces less TSH, which causes your thyroid activity to slow. If there is not enough T4 hormone the pituitary increases the amount of TSH to help speed up your metabolism.

Goitre

A goitre is when your thyroid gland becomes significantly swollen and enlarged – this can happen if your diet is low in iodine.

If you are iodine deficient your pituitary gland may try to compensate by overstimulating your thyroid to produce more thyroid hormone. When this happens your thyroid grows larger and larger.

The presence of goitre in your neck suggests your thyroid is not functioning properly or you are iodine deficient.

Other thyroid gland disorders

Several disorders are associated with the thyroid gland:

• Graves’ disease
• Hashimoto’s disease
• thyroid cancer
• thyroid nodules
• congenital thyroid disease
• iodine deficiency disorder.

Hyperthyroidism – overactive thyroid

Hyperthyroidism is a condition where your thyroid is overactive and releases too many T4 and T3 hormones into your bloodstream, creating a hormonal imbalance and causing your metabolism to speed up.

The most common cause of hyperthyroidism is an autoimmune condition called Graves’ disease.

Learn more about hyperthyroidism, including Graves’ disease and the symptoms and treatment of an overactive thyroid.

Hypothyroidism – underactive thyroid

Hypothyroidism is a condition where your thyroid is underactive and releases too little T4 and T3 hormones into your bloodstream.

This causes your metabolism to slow down too much and reduces the thyroid’s ability to make hormones.

The most common cause of hypothyroidism is an autoimmune condition called Hashimoto’s disease.

Learn more about hypothyroidism, including Hashimoto’s disease and the symptoms and treatment of an underactive thyroid.

Where to get help

• See your doctor
• See your endocrinologist
• Visit a GP after hours
• Ring healthdirect Australia on 1800 022 222.

Remember

• People with a family history of thyroid conditions have a higher risk of also getting thyroid and other autoimmune conditions.
• An overactive thyroid (hyperthyroidism) releases too much T4 and T3 into your blood stream and causes your metabolism to speed up.
• An underactive thyroid (hypothyroidism) does not release enough T4 and T3 into your blood stream and causes your metabolism to slow down too much.
• Thyroid conditions can be treated and have a good prognosis.
• Thyroid conditions affect more women than men.

Acknowledgements

Diabetes and Endocrine Health Network

This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.

See also

• 
  Hyperthyroidism (overactive thyroid)




• 
  Hypothyroidism (underactive thyroid)




• 
  Your family health history




• 
  Genetic conditions




• 
  Genetic testing

Thyroid gland | You and Your Hormones from the Society for Endocrinology

Where is my thyroid gland?

The thyroid gland is located at the front of the neck just below the Adam’s apple (larynx). It is butterfly-shaped and consists of two lobes located either side of the windpipe (trachea). A normal thyroid gland is not usually outwardly visible or able to be felt if finger pressure is applied to the neck.

click to enlarge

Diagram showing the location of the thyroid gland in the neck. It has two lobes and sits in front of the windpipe (trachea). The voice box (larynx) sits just above the thyroid. Image created using Biorender.

What does the thyroid gland do?

The thyroid gland produces hormones that regulate the body’s metabolic rate, growth and development. It plays a role in controlling heart, muscle and digestive function, brain development and bone maintenance. Its correct functioning depends on a good supply of iodine from the diet. Cells producing thyroid hormones are very specialised in extracting and absorbing iodine from the blood and incorporating it into the thyroid hormones.

Who tells the thyroid to produce and release hormones? 

The signal comes from a small gland located at the bottom of our brain called the pituitary gland. The pituitary gland produces and sends out a hormone called thyroid-stimulating hormone (TSH). TSH then tells the thyroid gland how much hormone to produce and secrete. TSH levels in your blood are rising and falling depending on your body’s needs, to produce more or less thyroid hormones.

The pituitary gland responds either directly to the thyroid hormones in the blood, but it also responds to signals from the hypothalamus, which sits above the pituitary gland as part of your brain. The hypothalamus releases its own hormone thyrotropin-releasing hormone (TRH). TRH in turn stimulates the release of TSH in the pituitary, which then signals to the thyroid gland.

This whole network is also referred to as the hypothalamic-pituitary-thyroid axis (HPT) and it adapts to metabolic changes and your body’s needs.

click to enlarge

Diagram showing the hypothalamic-pituitary-thyroid axis (HPT). The highlighted areas show the hypothalamus and the anterior pituitary. Image created using Biorender

Which hormones does my thyroid gland produce?

The thyroid gland produces thyroxine (referred to as T4), which is a relatively inactive prohormone, and the highly active hormone called triiodothyronine (referred to as T3). Collectively, thyroxine and triiodothyronine are referred to as the thyroid hormones. The thyroid gland produces just 20% of the highly active T3, and it mainly produces the prohormone T4, which constitutes about 80% of the secreted thyroid hormones. Once secreted by the thyroid, specific enzymes in other tissues like the liver or kidneys convert T4 into the active hormone T3 (which accounts for most of the T3 in the body).

In addition, there are other hormone-producing cells within the thyroid gland called C-cells. These cells produce calcitonin. Calcitonin plays a role in regulating calcium and phosphate levels in the blood, which is important for your maintain healthy bones.

What could go wrong with the thyroid gland?

Normally the thyroid gland produces the exact number of hormones needed to keep your body’s metabolism running and in balance. As described earlier, TSH secreted by the pituitary gland remains at a constant level in your blood circulation, but the level increases when the T4 levels fall and decrease when T4 levels in the blood rise. This hypothalamic-pituitary-thyroid feedback loop keeps the levels of T4 in your blood stable and reacts to small changes immediately.

However, there are several disorders associated with the thyroid gland with most problems concerning the production of thyroid hormones. Either the thyroid gland produces too much hormone (called hyperthyroidism), resulting in your body using energy more quickly than it should; or your thyroid doesn’t produce enough hormone (called hypothyroidism), resulting in your body using energy more slowly than it should. Rarely cancer of the thyroid gland may develop.

click to enlarge

Diagram showing the effects of the thyroid hormone on various organs. Image created using Biorender.

What are typical symptoms of hyper- and hypothyroidism?

Typical symptoms for hyperthyroidism are weight loss, fast (and sometimes irregular) heart rate, irritability/nervousness, muscle weakness and tremors, changes in menstrual periods, sleep problems, eye problems and heat sensitivity.

Symptoms for hypothyroidism include weight gain, slower heart rate, fatigue, menstrual period abnormalities, forgetfulness, dry skin and hair, hoarse voice and intolerance to cold.

In addition, both hyperthyroidism and hypothyroidism can be accompanied by an enlargement of the thyroid gland known as goitre.

Who is affected by thyroid disease?

On a worldwide scale, it is estimated that more than 200 million people have some form of thyroid disease. People of all ages and races can get thyroid disease. However, women are 5 to 10 times more likely than men to develop problems with their thyroid function.

What causes thyroid disease?

There are different factors that can cause hyper- and hypothyroidism.

The following conditions cause hypothyroidism:

Thyroiditis is inflammation of the thyroid gland. This can reduce the amount of thyroid hormones produced.

A special form of thyroiditis is Hashimoto’s thyroiditis. This is a genetic disorder that causes the immune system to make the thyroid gland underactive. Hashimoto’s thyroiditis often runs in families. In addition, thyroiditis can occur in women after giving birth, this is called postpartum thyroiditis. Postpartum thyroiditis is usually a temporary condition and occurs only in 5-9% of woman giving birth.

Nutrition also impacts the function of your thyroid gland. Iodine deficiency can cause hypothyroidism. This is a worldwide problem affecting approximately 100 million people. As mentioned earlier, iodine is used by the thyroid gland to produce hormones.

Medications, radioactive iodine treatment and thyroid surgery and conditions affecting the pituitary gland can also result in hypothyroidism.

The following conditions cause hyperthyroidism:

Graves’ disease is a condition where the immune system causes the thyroid gland to become overactive and produce too much hormone. Your thyroid gland might be enlarged and referred to as a diffuse toxic goitre.

Thyroiditis (inflammation) caused by a viral infection can trigger the release of hormones that were stored in the thyroid gland. This uncontrolled release of thyroid hormones causes hyperthyroidism for a few weeks or months, with thyroid function returning to normal in most cases.

Excessive iodine intake may have negative effects on your thyroid gland. High quantities of iodine are found in a number of drugs such as Amiodarone, Lugol’s solution (iodine), some cough syrups and contrast dyes used for some types of scans. This might cause the thyroid to produce either too much or too little thyroid hormones in some individuals.

Swelling and lumps can occur within the thyroid gland, and they are called nodules. Most thyroid nodules are harmless, but some can cause the overproduction of thyroid hormones. Rarely, thyroid nodules can be cancerous. In some cases, such as cancer, some or all of the thyroid gland is removed. You can live without your thyroid, but you need to take medicine daily to replace the hormones produced by your thyroid gland.

How can I promote the health of the thyroid gland?

Iodine is the critical ‘ingredient’ for the production of thyroid hormones. We don’t need a lot of iodine, but a daily and constant supply of this micronutrient is important. Too much iodine can cause problems with your thyroid gland as described above. The best way to get your daily dose of iodine is through eating foods like seafood and dairy products. In addition, iodized salt (salt with iodine added to it) is a good source of iodine and you can use it to season your food.

Last reviewed: Jan 2020

Testes

its functions and diseases – FGBU “NMITs TPM” of the Ministry of Health of Russia

The thyroid gland plays an important role in the work of our body, if it does not function properly, metabolic processes are disrupted, and other systems malfunction. It is no coincidence that one day of the year was dedicated to this organ – today, May 25, is World Thyroid Day.

Alla Makarovskaya, a doctor-endocrinologist of the National Medical Research Center for Therapy and Preventive Medicine of the Russian Ministry of Health, told about how the thyroid gland is arranged, what hormones it produces and what function it performs.

“The thyroid gland is one of the largest endocrine glands, located under the larynx, anterior to the trachea, consists of two lobes and an isthmus (has the shape of a butterfly).

The name “thyroid” was given to it by the anatomist Thomas Worth in 1656; iron in its shape reminded him of the shields of the warriors of Ancient Greece. And the first mention of the thyroid gland dates back to the 4th century BC. – they were found in the writings of Hippocrates and Plato, in the writings of physicians in ancient Greece, India and Egypt. According to WHO statistics, among endocrine disorders, thyroid diseases are the second most common after diabetes mellitus.

This “butterfly” gland has its own holiday: May 25 is World Thyroid Day. The date was proposed in 2008 by the European Thyroid Association.

The thyroid gland produces hormones: thyroxine (T4) and triiodothyronine (T3), which, released directly into the blood, affect all cells and tissues of the body, regulate the rate of various metabolic processes, thereby affecting the functions of all organs and systems .

In the blood, most of the thyroid hormones are associated with proteins, they are biologically inactive, and only a small fraction of hormones free from proteins actively performs their functions (free T3 and free T4). The “conductor” of the work of the entire endocrine system is the hypothalamic-pituitary system, which consists of two glands: the pituitary gland, located at the base of the brain, and the hypothalamus, located in the brain a little higher than the pituitary gland.

Thyroid, pituitary and hypothalamus work in concert to control thyroid hormone levels. If, for example, there is not enough thyroid hormone in the blood, the pituitary gland increases the production of its thyroid-stimulating hormone (or TSH), which stimulates an increase in the production of hormones by the gland. Once normal thyroid hormone levels are restored, TSH production slows down and approaches normal.

The state of normal functioning of the thyroid gland is called euthyroidism (“eu-” in Greek means “good”, “normal”). If the thyroid gland does not produce enough hormones, then the metabolic processes in the body slow down. This condition is called hypothyroidism.

If there is more thyroid hormone than necessary, the metabolism increases and the opposite state of hypothyroidism develops – hyperthyroidism.

The symptoms of hypo- and hyperthyroidism are not specific to thyroid disorders, they can be associated with completely different problems. In order to accurately assess the activity of the thyroid gland, it is enough to donate blood, in which the level of TSH, free T4 and free T3 is primarily assessed.

Goiter refers to an enlarged thyroid gland. Currently, an accurate method for determining its size and structure is ultrasound (ultrasound). Autoimmune thyroid diseases are widespread. Diseases of this type are diffuse toxic goiter (DTG) and autoimmune thyroiditis (AIT). Each of these occurs in about one in 100 people.

Other thyroid diseases are nodules, cancer, subacute thyroiditis. For the differential diagnosis of nodular goiter (thyroid nodules larger than 1 cm in diameter), a fine needle aspiration biopsy (FNA) is indicated.

You can make an appointment with an endocrinologist at the Consultative and Diagnostic Center of the National Medical Research Center for Therapy and Preventive Medicine of the Russian Ministry of Health by calling 8 (495) 790-71-72.

Pathology of the thyroid gland

The territory of Moscow and the Moscow Region belongs to areas with a low content of iodine in drinking water, which, along with ecology and carcinogenic food, leads to various diseases of the thyroid gland.

The thyroid gland is one of the most important organs of the human endocrine system. Thyroid hormones regulate such important body functions as metabolism, growth, mental development, the activity of the cardiovascular and digestive systems, participation in the regulation of sexual function. Thyroid dysfunctions include diseases hyperthyroidism and hypothyroidism .

Hypothyroidism syndrome (thyrotoxicosis) is more often diagnosed with diffuse toxic goiter (DTG) and is caused by increased production of thyroxine and triiodothyronine by the thyroid gland. DTG is diagnosed mainly in young and middle-aged women.

The exact cause of the development of the disease cannot be named for certain, however, the factors that provoke it are:

• autoimmune reaction of the body (production of antibodies that activate the thyroid gland and hormone production)
• mental trauma

Under the influence of any of these factors, the thyroid gland can increase in volume, increase the secretion of its hormones, which leads to the development of hyperthyroidism.

Hypothyroidism is a syndrome characterized by insufficient production of thyroid hormones (thyroxine and triiodothyronine).

Hypothyroidism is associated with neuropsychiatric disorders, metabolic and energy disorders in the body, swelling of the face, bradycardia (slow pulse). It is more common in women aged 30-50 years.

Symptoms of hyperthyroidism: psychosomatic disorders, the most common of which are excessive irritability, constant feeling of fatigue and weakness, increased sweating, heat intolerance, etc. General examination sometimes reveals a slightly enlarged thyroid gland, tachycardia, low or high blood pressure; weight decreases, diarrhea, lacrimation, “bulging eyes” are possible.

The cause of the disease can be:

• chronic thyroiditis
• congenital thyroid disorders
• environmental iodine deficiency
• surgery and trauma of the thyroid gland
• Radiation or thermal treatment of the gland
• treatment with iodine-containing drugs, antithyroid drugs.