BIOL-2230 Lecture Notes - Lecture 2: Zona Glomerulosa, Zona Fasciculata, Zona Reticularis
25 Jan 2017
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Document Summary
Gland composed of follicles made up of epithelial cells. In our throat: easy way to identify the thyroid, produce thyroglobulin (cuboidal follicular cells) Also contain parafollicular cells: produce calcitonin. Actually 2 separate hormones: t3: thyroglobulin with 3 iodine, t4: thyroglobulin with 3 iodine. Thyroid gland, brain, spleen, testes, and uterus don"t have receptors. Increases basal metabolic rate and heat production: increases cellular activity (mostly gives atp energy, calorigenic effect (body temperature) Maintains blood pressure: increases number of adrenergic receptors. Constricts blood vessels: gh controls tissue growth. Anterior pituitary secretes tsh which travels to thyroid gland via blood vessels. Tsh triggers production of thyroglobulin which accumulates in follicles. Tsh triggers active transport of iodine into follicles. Thyroglobulin is iodized (thyroglobulin + iodine) to form t1 and t2. T1 and t2 link to form t3 and t4. T3 and t4 are packaged into lysosomes. Lysosomal enzymes free t3 and t4 and release them into bloodstream.
