Lecture 15 - Thyroid Gland and Hormones

LECTURE 15:10/20 Thyroid Gland A. HPT Axis Brain (hypothalamus) PVN Dopamine NE (+) (-) Pituitary Gland TSH Growth! (-) Thyroid Gland Thyroid Hormones HPT axis long-loop feedback B. Thyroid disease prevalence Thyroid deficiencies: 13 million Americans 1 million women Va cases are probably undiagnosed large resevoir of TH in the blood Thchenge metabolism, sive change of metamsic offacts pulse foint 72 hody lamp 08°F 180", moved, Fulked, hoarse low voice BMRO Aware of surroundings (law) Died not whel Billed him, had a lumer that blant grow due to metaboliem. Me fumar sitten kim. C. Structure of thyroid gland Human thyroid Gross anatomy Single, unpaired gland Honda lege-shape in humans Follicles Launts of thyroid production located ventral to trachea in front of Trachea 2.Origin of thyroid gland develops from pharynx respiratory digestive tracks converge ventral evagination later detaches A. Follicular epithelial cells form thyroid follicles (filled with colloid) Thyroid follicle: Colloid inside view Filled with colloid (Tgb) Fluid that contains TO Secrete thyroid hormones Colloid Thyroid Siat facing lumen Follicular cell Follicle Thyroid follicle cell Mv microvili (77) not B. Parafollicular cells (C cells) Secrete Calcitonin biologically important Cacilerin - went dit whe 11 hypocalcemic hormone lowers plasma calcium blood Cabane Cat (Thane d)- Parafollicular (Cell) treatment for osteoporosis C. Complications parathyroid glands nat same as thyroid gland, allthough embedded within thyroid gland "sepperated within piece of CT secrete parathyroid hormone Parathyroid hypercalcemic hormone opp. to CT raises plasma Ca -accidental removal can lead to death (Hypercalcemic tetany) Collid no PTH, plasma Ca 4, impacts contraction of skeirtal muscle spasm of diaphragm can breathe D.TSH regulation of thyroid hormones okad Microvilli add I te tyrosine Apex On TgB (Tyrosine lelkered to TG1 In lumen fol felticle) DIT DIT follicular pithelial Thyroia hermones are produced outside the cell Basal nucleus in luman Base E. Chemical interference of TH Dietary iodide deficiency. reduced Ty plasma levels increased TSH secretion hypertrophy if long enough hyperplasia (extreme case) enlarged thyroid Soil poor in iodide Diagram 1: Colloid To make lumen I has to make it is the lumen loma Th I is transported out to the lumen Pendrin Tgb still tethered Why micrown/154 are important needs enough SA to TPO has enough places to go to allow creation of thyroid hormone TSH (+) TPO levels 2 coping (e) Tgb synthesis SPEC (+) iodide uptake by NIS by (+)p TSH Stimulates release "ending last phase, Ty not free yet by endosome endolysosome Tgb digestion by enzymes to liberate Tu T. T TT Deiodinase of Diagram 2: (A diagram of a cell with labeled structures) Diagram 3: (A diagram of a cell with labeled structures) Diagram 4: Brain (hypothalamus) TRH (-) Pituitary Gland TSH (-) Thyroid Gland Thyroid Hormones HPT axis long-loop feedback