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Sunday, February 5, 2012

Thyroid Gland and Hypothyroidism - Lesson 299

Where is Thyroid Gland?

This lesson will deal with thyroid gland and hypothyroidism and thyroid functions. The biggest endocrine gland in the human body is thyroid gland. It is situated in the neck inferiorly to the thyroid cartilage. Thyroid cartilage forms a prominence in that area named as Adam's apple. Thyroid gland consists of two lobes and isthmus is a bridge like structure that attaches two thyroid glands. Isthmus is situated under the cricoid cartilage. The two lobes of the thyroid gland are situated on both sides of the wind pipe or trachea. Thyroid gland functions as an important endocrine gland in the body. It has no ducts to pass their hormones into bloodstream. Thyroid gland secretes two important hormones, such as, thyroxine or tetraidothyroxine and triiodothyronine. Using iodine thyroid gland produces these hormones. Iodine is captured by thyroid glands from the blood and tyrosine. Thyroxine is much thicker hormone than triiodothyronine.

We will now see about thyroid gland and hypothyroidism. When thyroid gland secretes excess amount of hormones, this abnormal condition is called as hyperthyroidism. On the other hand, if the gland produces less hormones than human body requires normally that condition is called as hypothyroidism. The most common reason for hypothyroidism is deficiency of iodine. Stress is a main symptom associated with hypothyroidism. Congenital hypothyroidism is an abnormal condition of less secretion of thyroid hormones from the birth of a child. Other reasons for hypothyroid are may be due to any autoimmune disorders like Hashimoto's thyroiditis. If the thyroid gland is removed due 
to any thyroid cancer would also lead to hypothyroidism.

Functions of Thyroid Gland
The primary funciton of thyroid gland is to produce three hormones, such as, triiodothyronine (T3), calcitonin, and thyroxine (T4). These hormones are essential for body metabolism activity among body cells (T3 and T4). Thyroid hormones help to absorb oxygen by cells. Body metabolic rate is maintained by thyroid glands. Calcitonin controls the level of calcium in the blood and it pulls the excessive calcium in the blood to store in the bones. Thus it restores body's normal calcium level.

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To go to the prior lesson of Endocrine Tissue, please click the link below.