Thyroid Gland: Overview
Mar 03, · Thyroid Gland Basics. Thyroid problems can seem complex when you first look at them but they don't have to be. Your thyroid is a gland that sits at the base of your neck and it might be one of the most important (for its size) organs in your body. Your thyroid gland is a small gland, normally weighing less than one ounce, located in the front of the neck. It is made up of two halves, called lobes, that lie along the windpipe (trachea) and are joined together by a narrow band of thyroid tissue, known as the isthmus. The thyroid is situated just below your "Adams apple" or larynx.
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Skip to main content. Hormonal system endocrine. Home Hormonal system endocrine. Thyroid gland. Actions for this page Listen Print. Summary Read the full fact how to make flare skirt. On this page. Iodine for hormone production The pituitary gland Goitre Overactive thyroid hyperthyroidism Underactive thyroid hypothyroidism Other thyroid gland disorders Treatment for thyroid gland disorders Where to get help Things to remember.
Some of the more common hormonal disorders are associated with the thyroid gland, which is part of the endocrine system. This system is a collection of glands that secrete chemicals called hormones directly into the bloodstream.
Together with the nervous system and the immune system, the endocrine system helps the body to cope with different events and stresses. The thyroid gland secretes hormones to regulate many metabolic processes, including growth and energy expenditure. If the thyroid gland is overactive or sluggish, the metabolism will be affected, leading to a variety of symptoms that are easily misdiagnosed.
Around one in 20 people will experience some form of thyroid dysfunction in their lifetime. Women are more susceptible than men. Iodine for hormone production The thyroid gland produces two primary hormones - thyroxine also referred to as T4 and tri-iodothyronine also referred to as T3.
The numbers 3 and 4 refer to the number of atoms of iodine in the hormones. Iodine is essential for the production of thyroid hormones and humans need about mcg millionths of a gram each day. Iodine is found in most foods, especially seafood. The soils in Tasmania and along the Nody Dividing Range are low in iodine, so the food from these areas can contain insufficient iodine.
Iodised salt is the best way to supplement dietary iodine, but taking too much iodine can also be a problem. Of the two hormones produced, T3 is more active than T4, but is produced in much smaller quantities. T4 has a lesser effect, but most is converted to T3 by enzymes that remove one iodine atom. The greater gand amount of T3 and T4 circulating in the blood, the faster the metabolism. Lower amounts of T3 and T4 result in dor reduced metabolism.
The pituitary is located at the base of the brain. Its principal function is to monitor and regulate the activity of the other glands. The pituitary affects the thyroid gland by producing a hormone how to look pregnant with a pillow thyroid-stimulating hormone TSHwhich prompts the thyroid to release more T4 and T3.
If there is too much T4 circulating in the blood, the pituitary reduces the amount of TSH produced, which then causes thyroid activity to slow. If there is too little T4, the pituitary increases the amount of TSH. In this way, T4 and T3 levels in the blood are kept relatively constant. The pituitary gland, in turn, is overseen by a part of the brain qhat the hypothalamus.
A shortage of iodine in the diet is a common cause of goitre, especially in areas where the soil has little iodine. In attempting to make more thyroid hormone, the gland gets larger and larger.
This is also common with underactive thyroids, as the pituitary attempts to speed them up. Overactive thyroids can also produce goitres because their overactivity is wwhat due to overstimulation. Goitres indicate a problem with dles thyroid or iodine intake. Overactive thyroid hyperthyroidism An overactive thyroid releases too much T4 and T3 into the bloodstream, causing the metabolism to speed up too much.
This is an autoimmune condition in which antibodies behave like TSH and stimulate the tye uncontrollably. Complications of untreated hyperthyroidism include liver damage and heart failure, which can lead to death. Symptoms of an overactive thyroid include: Rapid pulse Tremor shaking of the hands Sweating and sensitivity to heat Weight loss despite an increased appetite Nervousness, agitation and anxiety Fatigue Diarrhoea Bulging eyes Goitre.
Underactive thyroid hypothyroidism An underactive thyroid releases too little T4 and T3 into the bloodstream, causing the metabolism to slow down too much. This is an autoimmune condition in which white blood cells and antibodies attack the thyroid gland. If not treated, the metabolism what are latin based languages called continue to slow and will ultimately in 10 to 15 years lead to death.
Symptoms include: Lethargy and fatigue Feeling cold even on warm days Unusual weight gain Depression Reduced concentration brain fog Puffiness of the face Hair loss Dry skin Constipation Goitre.
When these symptoms increase, the condition may be called myxoedema. Congenital hypothyroidism must be urgently treated to avoid serious brain damage. Rhe newborn babies are now screened for this condition. Other thyroid gland disorders Other disorders of the thyroid gland include: Nodules - lumps in the thyroid. Some are groups of uncontrollably overactive thyroid cells. These are generally harmless, but about 20 per cent yojr be cancerous. Cancer - thyroid cancer is uncommon and is readily treatable, especially if detected early.
Treatment for thyroid gland disorders Problems with thyroid hormone levels can be diagnosed with a simple blood test.
Underactivity is treated by taking thyroxine tablets - a form of hormone replacement. Overactivity is treated with drugs that slow the activity of the thyroid gland. If these do not work, part or all of the thyroid can be removed surgically, or some or all of the active thyroid cells can be killed with radioactive iodine. Nodules and cancers are diagnosed with a variety of different tests, including ultrasound, how to create scents for candles x-rays and fine needle biopsies.
Hot nodules will generally be removed surgically or destroyed with radioactive iodine. Cold nodules are frequently left alone and simply kept under observation. Cancer is treated by surgically removing the thyroid gland, followed by treatment with radioactive iodine to destroy any cells which may have spread.
Where to get help Your doctor Things to remember The thyroid gland regulates many metabolic processes, including growth and energy expenditure. Common problems include overactivity and underactivity of the thyroid gland. Most thyroid conditions are caused by autoimmunity. These conditions have a genetic link. People with a family history of thyroid conditions have a higher risk of also having a thyroid condition and other autoimmune conditions.
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It is the T3, derived from T4 or secreted as T3 from the thyroid gland, which is biologically active and influences the activity of all the cells and tissues of your body. What do my thyroid hormones do for me? The T4, or rather the T3 derived from it, and the T3 secreted directly by the thyroid gland influence the metabolism of your body cells. Your thyroid helps your body to regulate many functions including metabolism. The ingredients in Thytrophin PMG purport to have a synergistic effect, meaning the ingredients work together to help your body at a cellular level. When your metabolism does not work properly, your body does . Sometimes called the "master gland," the pituitary gland is the primary influencer of how your other glands operate. The pituitary gland secretes and stores hormones, which it uses to stimulate your other odishahaalchaal.com hormones regulate a variety of body functions, such as temperature, urine production, thyroid activity, growth in children, and the production of sex hormones (testosterone in men.
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Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. The thyroid gland is a butterfly-shaped organ located at the base of the neck in front of the trachea windpipe.
In infants, thyroid hormones are crucial to the development of the brain and the skeletal system. A normal functioning thyroid gland is critical to the normal development of children, and to both the long-term and minute-to-minute well-being of adults.
Essentially, the thyroid gland regulates your body's metabolism. Its job is to produce and release two major hormones— thyroxine T4 and triiodothyronine T3. These hormones help to regulate many crucial bodily functions such as:. The distinguishing feature of these hormones is that they contain iodine atoms; T3 has three iodine atoms and T4 has four.
Accordingly, the thyroid gland is unique in its specialized ability to pick up iodine from your bloodstream in order to incorporate it into your thyroid hormones. Because iodine isn't produced by the body naturally, it's important to make sure you're getting enough through your diet in order to keep your thyroid functioning well.
All T4 in your body is produced by the thyroid gland—about 80 to micrograms mcg per day. Roughly 10 times that amount of T4, about mcg, is constantly circulating in your blood.
Only the small proportion of circulating T4 that is unbound, known as free T4, is immediately available for your body to use. Generally, around half of this amount is converted to T3 by cleaving off one of its four iodine atoms.
The remainder is converted to reverse T3 rT3 by cleaving off an iodine atom from a different location. T3 is the active thyroid hormone, while rT3 is completely inactive. T3 is degraded much more rapidly than T4.
Thyroid hormones have an impact on every cell and every organ. Some of the intracellular T4 is converted to T3, and some of the T3 binds to specific T3-receptors in the nucleus of the cell. This bound T3 causes nuclear DNA to stimulate or inhibit the production of specific proteins. Among these proteins are various enzymes that, in turn, control the behavior of many important bodily functions mentioned above, such as how quickly your food is digested, your heart rate, body temperature, and how fast calories are burned.
Though thyroid hormones regulate DNA in this way in all cases, different cells in your body have different kinds of T3-nuclear receptors and in different concentrations. As such, the effect of T3 on a cell is quite variable from tissue to tissue and under various circumstances. Any time a physiological system is this critical, there are complex layers of regulation aimed at assuring that it is finely tuned to do what it needs to do and that its function is controlled within a narrow range.
This is certainly true when it comes to the thyroid, which is part of the endocrine system. Here's a brief look at the major layers of thyroid regulation:. The pituitary-thyroid axis provides the chief control over the thyroid gland itself. The pituitary gland, which is located deep within the brain, releases a thyroid stimulating hormone TSH , causing the thyroid gland to increase its production and release of T3 and T4.
At the same time, circulating thyroid hormone, specifically T3, inhibits TSH production by the pituitary gland, thus forming a negative feedback loop. So, as T3 blood levels increase, TSH levels fall.
This feedback loop operates to keep the production of thyroid hormone by your thyroid gland within a narrow range. The pituitary gland is also prompted to release TSH when the hypothalamus releases thyrotropin-releasing hormones TRH. When the hypothalamus releases TRH, this causes the pituitary gland to release more TSH, which in turn increases thyroid hormone production. As mentioned previously, over 99 percent of the thyroid hormone in your bloodstream is bound to proteins in your blood, chiefly TBG, rendering the hormone inactive.
Only free T4 and T3 have any physiologic activity. This protein binding of the thyroid hormones serves several critical regulatory functions, including:. As we have seen, T3 and T4 do their important work inside of your cells. Given the complexity of all of this, it probably isn't hard to imagine that there's a lot of opportunity for something to go wrong. Thyroid disorders can occur with diseases affecting the thyroid gland itself or with conditions affecting the hypothalamus, pituitary, or blood proteins, or even with disorders affecting the handling of thyroid hormones by various tissues of the body.
In general, disorders of the thyroid system tend to cause thyroid function to become either underactive hypothyroid or overactive hyperthyroid. In addition to these general problems, the thyroid gland can become grossly enlarged, a condition called a goiter and people can develop cancer of the thyroid. Any of these conditions are potentially very serious. The symptoms of thyroid disease can be quite variable from individual to individual. Common symptoms of hypothyroidism often include:.
Common symptoms of hyperthyroidism include:. Diagnosing a thyroid disorder requires a careful analysis of screening thyroid blood tests and additional testing if a thyroid condition is suspected. In diagnosing a thyroid disorder , assessing the pituitary-thyroid relationship is particularly critical.
This can generally be done by measuring the amount of total T3 and free T4 in your blood, as well as your TSH blood levels. In some cases, the proper interpretation of TSH levels can be tricky and controversial. If your TSH levels are elevated and your free T4 levels are low, this likely indicates that your thyroid gland is not producing enough hormone and your pituitary gland is attempting to whip up its function, which may indicate hypothyroidism. However, in rare instances high TSH levels could also be related to a pituitary tumor.
If your TSH levels are low and your free T4 levels are high, it may mean that your thyroid gland is producing too much thyroid hormone, but low TSH levels could also signify pituitary disease. Your endocrinologist should be able to provide a comprehensive diagnosis for you and may recommend additional testing if necessary. The thyroid gland and the hormones it produces are critically important to human development and to a healthy life.
The critical nature of thyroid function is reflected in the complex mechanisms that nature has established for the regulation of thyroid hormones. Because the thyroid system is so important to our everyday functioning, it's crucial to properly diagnose and treat any problems that occur. If you have symptoms of either hypothyroidism or hyperthyroidism, be sure to tell your doctor so you can be tested.
Losing weight with thyroid disease can be a struggle. Our thyroid-friendly meal plan can help. Sign up and get yours free! Brent GA. Mechanisms of Thyroid Hormone Action. The Journal of Clinical Investigation. Thyroid Hormone Regulation of Metabolism. Physiological Reviews. Your Privacy Rights. To change or withdraw your consent choices for VerywellHealth. At any time, you can update your settings through the "EU Privacy" link at the bottom of any page.
These choices will be signaled globally to our partners and will not affect browsing data. We and our partners process data to: Actively scan device characteristics for identification. I Accept Show Purposes. Table of Contents View All. Table of Contents. Thyroid Disorders. T3 then does the work. To prevent the accumulation of too much circulating T4, excess T4 is converted to inactive rT3, which is then metabolized by your tissues. Hormone release from the hypothalamus.
The levels of free circulating thyroid hormones that are available to your tissues are buffered, on a minute-to-minute basis, by TBG and the other thyroid-binding blood proteins. This ensures that plenty of thyroid hormone is available to your tissues at all times, but at the same time allows for extremely fine control of the thyroid-DNA interface within individual cells. Was this page helpful?
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