Thyroid hormones are chemical substances produced by the thyroid gland. The thyroid gland is located in the front of the neck. The thyroid gland uses iodine to make thyroid hormones. Thyroid hormones are known to be essential for the functions of every cell in the body. Thyroid hormones help regulate growth and the rate of chemical reactions also known as metabolism. The thyroid hormones are also involved in rhythms that govern sleep together with other essential functions.
The two most important thyroid hormones are thyroxine or T4 and triiodothyronine or T3. Thyroid stimulating hormones or TSH are produced by the pituitary gland. The thyroid stimulating hormones sole responsibility is to stimulate the thyroid to produce thyroid hormones. The pituitary gland on the other hand is stimulated by the hypothalamus gland in the brain to produce more thyroid stimulating hormones or TSH.
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Thyroid Hormone Levels
There are a lot of different blood tests used to measure thyroid hormone levels. When one is being tested for hypothyroidism, most of the time, doctors order a thyroid stimulating test or TSH test. The normal TSH levels are found to be in between 0.5 and 5.5 mlu/L. Conventional doctors consider the TSH test as the best way to determine if an individual is suffering from any thyroid problems. Free T3 and free T4 tests measure the amount of unbound T3 and T4 in the blood. The normal range of T3 is from 230 to 420pg/dL. As for T4, the normal range is from 0.8 to 1.8 ng/dL. Laboratories provide different normal ranges as lab test results are based on instruments used. There are two tests that measure the presence of thyroid antibodies in the blood. Thyroid antibodies are nearly undetectable if functioning correctly. If thyroid antibodies are significant, most likely there would be an issue with the thyroid function. The presence of thyroid antibodies affects all the other thyroid tests.
Interesting Questions about Thyroid:
The thyroid is a small, butterfly-shaped gland just below the Adam’s apple. This gland plays a very important role in controlling the body’s metabolism, that is, how the body functions. It does this by producing thyroid hormones (T4 and T3), chemicals that travel through the blood to every part of the body. Thyroid hormones tell the body how fast to work and use energy.
The thyroid gland works like an air conditioner. If there are enough thyroid hormones in the blood, the gland stops making the hormones (just as an air conditioner cycles off when there is enough cool air in a house). When the body needs more thyroid hormones, the gland starts producing again.
The pituitary gland works like a thermostat, telling the thyroid when to start and stop. The pituitary sends thyroid stimulating hormone (TSH) to the thyroid to tell the gland what to do.
About 20 million Americans have some form of thyroid disease. Many are undiagnosed or misdiagnosed. No age, economic group, race, or sex is immune to thyroid disease.
The thyroid gland might produce too much hormone (hyperthyroidism), making the body use energy faster than it should, or too little hormone (hypothyroidism), making the body use energy slower than it should. The gland may also become inflamed (thyroiditis) or enlarged (goiter), or develop one or more lumps (nodules).
| Fact: | Two of the most common thyroid diseases, Hashimoto’s thyroiditis and Graves’ disease, are autoimmune diseases and may run in families. |
| Fact: | Hypothyroidism is 10 times more common in women than in men. |
| Fact: | One out of five women over the age of 75 has Hashimoto’s thyroiditis, the most common cause of hypothyroidism. |
| Fact: | Thyroid dysfunction complicates 5%-9% of all pregnancies. |
| Fact: | About 15,000 new cases of thyroid cancer are reported each year. |
| Fact: | One out of every 4,000 infants is born without a working thyroid gland. |
Hyperthyroidism makes the body speed up. It occurs when there is too much thyroid hormone in the blood (“hyper” means “too much”). Nearly 10 times more frequent in women, it affects about 2% of all women in the United States.
The most common cause of hyperthyroidism, Graves’ disease, is caused by problems with the immune system and tends to run in families. It affects at least 2.5 million Americans, including Olympic athlete Gail Devers who won a gold medal in track after being diagnosed with and treated for Graves’ disease.
Symptoms include:
- fast heart rate
- nervousness
- increased perspiration
- muscle weakness
- trembling hands
- weight loss
- hair loss
- skin changes
- increased frequency of bowel movements
- decreased menstrual flow and less frequent menstrual flow
- goiter
- eyes that seem to be popping out of their sockets.
The symptoms of hyperthyroidism rarely occur all at once. However, if you have more than one of these symptoms, and they continue for some time, you should see your doctor.
Hypothyroidism causes the body to slow down. It occurs when there is too little thyroid hormone in the blood (“hypo” means “not enough”). Hypothyroidism affects more than 5 million people, many of whom don’t know they have the disease. Women are more likely than men to have hypothyroidism.
Also, one out of every 4,000 infants is born with the condition. If the problem is not corrected, the child will become mentally and physically retarded. Therefore, all newborns in the United States are tested for the disease.
Symptoms in adults include:
- feeling slow or tired
- feeling cold
- drowsy during the day, even after sleeping all night
- slow heart rate
- poor memory
- difficulty concentrating
- muscle cramps
- weight gain
- husky voice
- thinning hair
- dry and coarse skin
- feeling depressed
- heavy menstrual flow
- milky discharge from the breasts
- infertility
- goiter
Many of the symptoms of hypothyroidism can occur normally with aging, so if you have one or two of them, there is probably no reason to worry. However, if you are concerned about any of these symptoms, you should see your doctor.
Have more questions? Need more answers? Check our Full Thyroid FAQ
Thyroid Hormone Synthesis
The organification of iodine is the first step in the synthesis of thyroid hormones. Iodide is first taken up, converted to iodine and then eventually condenses onto tyrosine residues. This resides along the polypeptide backbone of a protein molecule. A protein molecule is called thyroglobulin. A coupling reaction is another synthetic reaction. It is closely linked to organification. This is where the iodotyrosine is coupled together. Thyroxine or T4 is the result of the formation of two di-iodotyrosine. Triiodothyronine or T3 formation is the result of a di-iodotyrosine and mono-iodotyrosine coupled together. The only way to attain or achieve normal levels of thyroid hormone synthesis is to have an adequate supply of iodine.
Functions of Thyroid Hormones
The functions of a thyroid hormone includes increase body metabolism by increasing the rate at which cells use up oxygen and food to produce energy, increase heart rate and force of contraction of the heart muscle, maintains normal sensitivity of respiratory centres, stimulate both the formation of red blood cells to enhance oxygen delivery and activity of other endocrine tissues and ensure proper skeletal development in children. Another function of the thyroid hormones is to allow the cardiovascular system to be more sensitive with the sympathetic nervous activity. Thyroid hormones affect almost every cell in the body.
Thyroid FAQ & Links to Related Articles
Parathyroid |
There are four parathyroid glands that are normally having the size of a single rice grain. In some normal cases, they can be as big as the size of a pea. |
Hypothyroid |
Also called underactive thyroid, hypothyroidism is a disorder that is characterized by abnormal level of thyroid hormones in the body, which is too low. |
Thyroid Glands |
The thyroid is a butterfly (pear)-shaped gland, it consists of 2 symmetrical lobes joined by a central isthmus that normally covers the 2nd & 3rd tracheal rings. |
Congenital Hypothyroidism |
Congenital hypothyroidism is a thyroid gland disorder that may lead to deafness or mental retardation if left undetected. |
Thyroid Depression |
Hypothyroidism can cause depression. Most people don?t realize that this feeling is depression caused by the thyroid gland not functioning as it should. |
Papillary Thyroid Cancer |
Papillary thyroid cancer is one of the thyroid cancer types. This type of thyroid cancer arises from the follicles in the thyroid gland. |
Thyroid Gland Function |
The thyroid gland is located immediately below the larynx on each side of and anterior to the trachea. It is one of the largest of the endocrine glands |
Thyroid Hormone |
These thyroid hormones are responsible in regulating the body?s metabolism, which is how much food will be broken down into useful energy for consumption. |
Thyroid Levels |
When the thyroid gland produces too much thyroid hormone, one may suffer from hyperthyroidism. |
Thyroid Stimulating Hormone |
The thyroid stimulating hormone is produced by the pituitary gland. The thyroid stimulating hormone promotes the growth of the thyroid gland. |
Thyroid Hormones |
Thyroid hormones are chemical substances produced by the thyroid gland. The thyroid gland is located in the front of the neck. |
Supplements for the Thyroid |
Natural thyroid supplements are helpful as a remedy to thyroid disorders. Its natural ingredients assure one of its safeties in taking it. |
Thyroid Symptoms in Women |
The thyroid gland is an endocrine gland that is the primary responsible in regulating the body?s metabolism. |
Thyroid Surgery |
Thyroid surgery is used to treat people with thyroid problems such as thyroid cancer, thyroid nodules and hyperthyroidism. |
Thyroid Test |
Thyroid tests or thyroid function tests are done to check the thyroid function in one?s body. A doctor will be able to determine and diagnose the thyroid disorder. |
Thyroid Treatment |
Treatment for thyroid disorders should be done to prevent unwanted results caused by the severity of the condition. Consult a physician for more of these treatments. |
Thyroidectomy |
Thyroidectomy is a surgical process wherein the whole or a part of the thyroid gland is removed. This surgical process is used to treat thyroid disorders. |
Underactive Thyroid |
Having an underactive thyroid is a minor problem but it seeks proper attention to avoid further health problems. Consult a physician about any thyroid problem. |
Low Thyroid |
Low thyroid, also known as hypothyroidism, is a condition where the thyroid gland is under active. |
Underactive Thyroid Diet |
Following a healthy meal plan, exercise and proper medication goes hand in hand to treat hypothyroidism. Consult a physician for a more individualized plan. |
Thyroid Cancer Treatment |
Each thyroid cancer treatment depends on the type of thyroid cancer and the extent or stage of the thyroid cancer one is suffering from. |
Parathyroid Hormone Levels |
Parathyroid hormones are considered to be the most important endocrine regulator. It basically regulates the calcium and phosphorus concentration in the body. |
Parathyroid Disease |
Studies show that since 1925, the standard treatment for parathyroid disease is to surgically remove the parathyroid gland(s) which are overproducing parathyroid hormones. |
Parathyroid Adenoma |
Parathyroid adenoma is a small tumor of the parathyroid gland and is known to be the most common disorder of the gland. |
Medullary Thyroid Cancer |
Medullary thyroid cancer is one of the types of thyroid cancer. This type of thyroid cancer is more common in women than in men. |
Overactive Thyroid |
Most people don?t feel any symptoms. Others can just lose weight and just feel depressed for no reason at all. |
Hypothyroidism |
Suppose you go in for a routine checkup and your doctor decides to test your thyroid function. You?ve experienced no thyroid disease symptoms |
Hypothyroidism Symptoms |
Hypothyroidism develops for over a long period of time. It?s normally from several months to even several years. |
Hypothyroidism Natural Treatment |
People who are suffering from hypothyroidism are advised to get plenty of exercise and have a balanced and healthy diet. The diet must be rich in protein and iodine. |
Hypothyroidism Diet |
Self medicating one?s thyroid disorder with hypothyroidism diet pills without proper information of the diet pill does not address the problem. |
Hyperthyroidism Symptoms & Treatment |
Hyperthyroidism is when the thyroid gland is overactive and produces too much thyroid hormones more than the body needs. |
Hypothyroidism |
Hypothyroidism is one of the chronic diseases in the world. Hypothyroidism is also known as underactive thyroid; hypo means under or below normal. |
Anaplastic Thyroid Cancer |
Anaplastic thyroid cancer is a type of thyroid cancer that is rare and aggressive. It affects the thyroid gland and most especially its function. |
Thyroid Disorders |
Problems arise if the thyroid gland is overactive or underactive. There are three common thyroid disorders. These are hypothyroidism, hyperthyroidism and the thyroid nodules. |
Thyroid Hair Loss |
Hair loss may happen for so many reasons but it is commonly associated to thyroid problems such as hyperthyroidism and hypothyroidism. |
Thyroid Function Test |
Thyroid Function Tests are the different tests conducted to assess and determine the cause of an individual?s thyroid problems. |
