Thyroid - Definition

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The thyroid is an endocrinal gland, meaning it is specialized in synthesizing hormones that produce an effect on the body. It is located in the neck, in front of the trachea. This organ is composed of two lobes, separated by the isthmus. It synthesizes the T3 and T4 thyroid hormones by a process of iodine binding to a protein, induced by TSH, the thyroid-stimulating hormone that regulates the thyroid functions. Thyroid hormones perform many different functions in the body, acting by stimulating the majority of organ activity. The thyroid gland can be affected by several conditions, including autoimmune diseases caused by the body's antibodies attacking the thyroid cells, deficient iodine supply from the diet causing thyroid deficiency, benign nodules causing overactivity of the thyroid, cancer, and more. Thyroid anomalies can be detected by assessing TSH concentration, the thyroid can be visualized by ultrasonography, and its activity can be analyzed by scintigraphy.