BIO 3422 Lecture Notes - Lecture 6: Anterior Pituitary, Follicular Cell, Pituitary Gland
16 Dec 2017
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Document Summary
Colloid- center of follicle, building blocks to make thyroid hormones located here (contains iodide) Thyroid releasing hormone (trh): trophic hormone released by hypothalamus. Thyroid stimulating hormone (tsh): trophic hormone released by anterior pituitary. Thyroid hormone (t3,t4): synthesis begins in the colloid and completed in the follicular cells: actions: Hyperthyroidism: t3, t4 negatively feedback to anterior pituitary = decrease tsh and hypothalamus = decrease trh. Break down protein (increase protein catabolism) to produce atp. Muscle weakness: hyper excitable/oversensitive reflexes, increase b receptors = increase/rapid hr. No goiter because tsh receptors not excessively stimulated: graves disease. Goiter- caused by excessive stimulation of tsh receptors on thyroid. Hypothyroidism: deficiency of iodine = decrease/reduced secretion of thyroid hormones t3, T4 negatively feedback to hypothalamus = increase trh and anterior pituitary = increase. Tsh which stimulates thyroid to increase t3, t4 resulting in goiter (enlargement of thyroid gland). Use less atp = decrease protein synthesis (brittle nails, hair fall out).
