2. Thyroid gland The thyroid gland is a butterfly-shaped endocrine gland that is normally located in the lower front of the neck (The breathing airway, or trachea), and below the larynx, or voice box. الحنجرة
3. Thyroid gland The thyroid’s job is to make thyroid hormone, which is secreted into the blood and then carried to every tissue in the body.
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6. Thyroid gland The thyroid gland is composed of a mass of hollow spheres or follicles . Each follicale has a lining one cell thick, and contains a jelly –like colloid ( Colloid is a glycoprotein ) lining
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10. Thyroid gland Steps Of Biosynthesis and Secretion Second (Iodination) Iodide react with the tyrosine that is an integral part of the giant thyroglobulin molecule which is produce by The follicle cells of the thyroid.
11. Thyroid gland Steps Of Biosynthesis and Secretion Second (Iodination) Tyrosine binding with two atoms produces diiodotyrosine (DIT). Thyroid peroxidase (TPO) is the enzyme that catalyzes this reaction.
12. Thyroid gland Steps Of Biosynthesis and Secretion Third (Coupling) The molecules must be combined to create the hormones
13. Thyroid gland Steps Of Biosynthesis and Secretion Fourth (Pinocytosis) The thyroid hormones are stored with the thyroglobulin until they are needed.
14. Thyroid gland Steps Of Biosynthesis and Secretion Finally (Secretion) The hormones are separated from the thyroglobulin and secreted into the blood stream through proteolysis of Tg. Excess released iodotyrosines (MIT and DIT) are deiodinated in situ and the resulting I- returns to be utilized in the intrathyroidal iodine cycle.
19. Thyroid gland Thyroid hormones regulation The thyroid gland concentrates iodine that the body absorbs from various foods to make thyroid hormones. The thyroid gland makes mostly T4. Very little T3 is made by the thyroid gland. The liver and other organs convert T4 into T3. Certain diseases and drugs can affect the conversion of T4 into T3.
21. Thyroid gland Thyroid hormones regulation Increased levels of T3 and T4 prompt the hypothalamus to slow down the production of TRH, this resulting in a decreased activity of TSH until the T3 and T4 levels have decreased again.
22. Thyroid gland Thyroid hormones regulation Decreasing levels , our hypothalamus to produce (TRH), which will signal the pituitary gland to produce TSH, which will stimulate the thyroid´s production of T3 and T4.
28. Thyroid gland Thyroid Function Tests Thyroid Antibody Tests Thyroid antibody test is usually ordered for patients who have a goiter, abnormal T3, T4 or TSH hormone levels, or other indications of thyroid disesase or thyroid disease risk.
