Physiology 3120 Lecture Notes - Lecture 3: Calcitriol, Bone, Biomineralization

• School: Western University
• Department: Physiology
• Course: Physiology 3120
• Professor: Tom Stavraky

Document Summary

Hypothalamus releases trh and srif trh stimulates anterior pituitary to release tsh tsh goes to thyroid follicles through bloodstream to stimulate t3/t4 release. Thyroid hormones act over long periods of time to regulate metabolism and hr (more next lecture) If too much t3/t4, negative feedback regulation where receptors on hypothalamus and anterior pituitary binds to t3/t4 to inhibit further trh/tsh release. On top of that, also have srif released by hypothalamus into anterior pituitary to inhibit further tsh release (less common mechanism) Need to bring in iodine from basolateral side apical side where tpo is. Na-i symporter uses na gradient to drive na and i transport from blood on basolateral side to colloid on apical side. Pendrin is symporter on apical side that transports i from parafollicular cell to colloid where. Tpo couples tg to i to get tg-t3/t4. Tg-t3/t4 complex goes back into cell via pinocytosis. In parafollicular cell, intracellular enzymes separate t3/t4 from tg.