BIO 12D Lecture Notes - Lecture 30: Thyroid, Thyrotropin-Releasing Hormone, Anterior Pituitary
3 Dec 2020
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Document Summary
Insufficient amounts of thyroid hormones (hypothyroidism) before and after birth can result in cretinism a disease characterized by dwarfism and mental retardation. It can be caused by a congenital lack of a thyroid gland, inability of the gland to produce. T3/t4 due to a genetic defect, or a lack of iodine in the diet. A disease resulting in enlargement of the thyroid gland. Insufficient iodine in the diet or too much thyrotropin releasing hormone (trh)/ thyroid stimulating hormone (tsh) can cause it. A hypothalamic tumor can cause excess secretion of trh and tsh. This produces large amounts of thyroid hormone and excess tsh will make it grow uncontrollably. Without iodine in the blood, the thyroid will be unable to produce t3/t4, so there will be no negative feedback to the hypothalamus and pituitary. Therefore, they will continue to secrete trh/tsh, and the excess tsh will enlarge the thyroid. A protein hormone secreted by the parafollicular cells/c cells of the thyroid.
