Thyroid Gland

Thyroid Gland Image
Location of Thyroid Gland

Thyroid is a small gland (about 2 inches long) which has the shape like a butterfly that lies in the front of your neck. It has two sides called lobes, located either side of your windpipe. Further, these two lobes of the gland are connected by a small tissue called the isthmus.

Thyroid is a vital hormone gland which plays a major role in metabolism, growth, development, temperature, weight and heart rate of the human body by constantly releasing a steady amount of thyroid hormones (T3 and T4) into the bloodstream. Also, during infancy and childhood, adequate thyroid hormone is crucial for brain development.

How the Thyroid Gland Works

Thyroid gland produces two type of hormones T3 and T4 by absorbing iodine from the food you eat. These hormones controls the body’s metabolism and are necessary for all the cells in your body to work normally. In other words, thyroid hormones regulates the speed with which your body cells work.

If too much of the hormones are released by the thyroid gland, then your body cells work faster than normal, and you have hyperthyroidism. On the other hand, if too little of the thyroid hormones are produced, then cells and organs of your body slow down, and you have hypothyroidism. Therefore, it is important that T3 and T4 levels are neither too high nor too low in your body. 

The two thyroid hormones are:

  • T3 – Triiodothyronine: This hormone contains three atoms of iodine and is often called T3.
  • T4 – Thyroxine: This hormone contains four atoms of iodine and is often called T4.

How Thyroid Gland produce hormones as needed?

To produce the right amount of hormones, the thyroid gland needs the help of pituitary gland. The pituitary gland produces a hormone called thyroid-stimulating hormone (TSH) which tells the thyroid gland how much hormones (T3 and T4) to produce.

Moreover, the pituitary gland monitors and controls the amount of thyroid hormones in your bloodstream:

  • When T3 and T4 levels are low in your body then pituitary gland makes more TSH to tell the thyroid to produce more thyroid hormones.
  • When T3 and T4 levels are high pituitary gland makes less TSH.

Please note, TSH levels that are too high or too low can indicate your thyroid is not working properly.

Thyroid disease

  • Hypothyroidism: It is a condition in which thyroid gland does not produce enough thyroid hormones. It is also called under active thyroid or low thyroid, which can slow down the metabolism rate of your body and can decrease the cardiac activity. (read more)
  • Hyperthyroidism: It is a condition in which thyroid gland produces too much hormones. It is also called overactive thyroid. Hyperthyroidism can accelerate the metabolism rate of your body. As a result, it can cause weight loss and irregular heart activity. (read more)
  • Goiter: A Goiter is an abnormal enlargement of thyroid gland. It indicates a condition, in which thyroid grows abnormally. Goiter commonly develops as a result of iodine deficiency or due to thyroid problem. (read more)
  • Graves’ Disease: It is an autoimmune disorder that cause an over active thyroid gland and results in an over production of thyroid hormones (Hyperthyroidism). In this disease, your immune system creates antibodies known as thyroid-stimulating immunoglobulins (TSI). These antibodies then attach to healthy thyroid cells and can cause your thyroid to create too much thyroid hormone. (read more)
  • Hashimoto’s Disease: Hashimoto’s Disease in an autoimmune disorder in which the immune system mistakenly attacks the thyroid gland. This can lead to hypothyroidism, a condition in which thyroid does not make enough hormones for body’s need. (read more)
  • Thyroid Nodules: The term thyroid nodule refers to an abnormal growth of thyroid cells that forms a lump within the thyroid gland. It can be solid or filled with fluid. Most thyroid nodules aren’t serious and don’t cause symptoms. Only a small percentage of thyroid nodules are cancerous. (read more)
  • Thyroid Cancer: It is a disease in which malignant (cancer) cells form in the tissues of the thyroid gland. The malignant cells begin multiplying in your thyroid and, once there are enough of them, they form a tumor. If it’s caught early, then thyroid cancer is one of the most treatable forms of cancer. (read more)

Thyroid Tests

Doctors use thyroid tests to check how well your thyroid gland is working. Thyroid tests also help your doctor to diagnose and find the cause of thyroid diseases such as:

  • Hypothyroidism
  • Hyperthyroidism
  • Goiter
  • Graves’ Disease
  • Thyroiditis
  • Hashimoto’s Disease
  • Thyroid Nodules
  • Thyroid Cancer

Tests for Thyroid include:

  1. Physical Examination
  2. Blood tests
  3. Imaging tests

Physical Examination: Your doctor will ask you questions about your medical history and perform a physical examination. Your doctor will check your neck to see whether the thyroid gland is enlarged or has thyroid nodules. Depending on the results of the physical examination, your doctor may also do other tests, such as Blood Tests and Imaging Tests.

Blood Tests: To know how well your thyroid gland is functioning, your doctor usually measure the levels of thyroid hormones in your blood. Your doctor may order one or more blood tests to check the levels of thyroid hormones in your blood.

Further, blood tests are done by taking blood from a vein in your arm. Blood Tests may include:

  • Thyroid stimulating hormone (TSH) test: TSH is a hormone produced and released into the bloodstream by the pituitary gland (a pea-sized structure) which is located at the base of your brain. TSH tells your thyroid gland how much T4 and T3 to make.

    Doctors usually check the amount of TSH in your blood first. Because, a high TSH level means you have hypothyroidism. This means that your thyroid gland is not making enough thyroid hormone. However, a low TSH level means you have hyperthyroidism. This means that your thyroid is making too much thyroid hormone.

    Therefore, the level of TSH (thyroid-stimulating hormone) in your blood is the best indicator of your thyroid function.

  • Triiodothyronine (T3) test: T3 test help doctors to diagnose hyperthyroidism or to show the severity of hyperthyroidism.

  • Free Triiodothyronine (FT3) test

  • Thyroxine (T4) test: T4 is one of the main thyroid hormones. A high level T4 in your blood usually means you have hyperthyroidism. However, a low level of T4 in your blood may mean you have hypothyroidism.

  • Free thyroxine (FT4) test

Additional Blood Test: In addition to above mentioned blood tests, your doctor may also order Thyroid Antibody Tests.

  • Thyroid Antibody Test: This test measures the level of thyroid antibodies in your blood. Thyroid antibodies are made when your immune system mistakenly attacks the healthy cells of your thyroid gland. This is known as an autoimmune disorder. Moreover, the presence of thyroid antibodies in your blood suggests that the cause of thyroid disease is an autoimmune disorder, such as Hashimoto’s disease or Graves’ disease. Types of Thyroid Antibodies are as following:

    • Thyroid peroxidase antibodies (TPO): These antibodies can be a sign of Hashimoto’s disease or Graves’ disease.
    • Thyroglobulin antibodies (Tg): These antibodies can also be an indication of Hashimoto disease. Most people with Hashimoto disease have raised levels of both Tg and TPO antibodies.
    • Thyroid stimulating hormone (TSH) receptor: These antibodies can be a sign of Grave’s disease.
    • Thyroid peroxidase antibodies (TPO): These antibodies can be a sign of Hashimoto’s disease or Graves’ disease.
    • Thyroglobulin antibodies (Tg): These antibodies can also be an indication of Hashimoto disease. Most people with Hashimoto disease have raised levels of both Tg and TPO antibodies.
    • Thyroid stimulating hormone (TSH) receptor: These antibodies can be a sign of Grave’s disease.
    • Thyroid peroxidase antibodies (TPO): These antibodies can be a sign of Hashimoto’s disease or Graves’ disease.
    • Thyroglobulin antibodies (Tg): These antibodies can also be an indication of Hashimoto disease. Most people with Hashimoto disease have raised levels of both Tg and TPO antibodies.
    • Thyroid stimulating hormone (TSH) receptor: These antibodies can be a sign of Grave’s disease.
    • Thyroid peroxidase antibodies (TPO): These antibodies can be a sign of Hashimoto’s disease or Graves’ disease.
    • Thyroglobulin antibodies (Tg): These antibodies can also be an indication of Hashimoto disease. Most people with Hashimoto disease have raised levels of both Tg and TPO antibodies.
    • Thyroid stimulating hormone (TSH) receptor: These antibodies can be a sign of Grave’s disease.

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