Thyroid & Parathyroid Glands

Thyroid & Parathyroid Glands

1. Anatomy of thyroid gland

   • Sits inferior to thyroid cartilage of larynx
   • Left & right lobes connected by narrow isthmus
   • Rich vascularization gives it reddish color

2. Thyroid gland composed of microscopic follicles

   • Follicular cells are cubodial epithelial cells that surround a central lumen
     • Produce & release thyroid hromone
   • Colloid - viscous, protein-rich fluid
   • Parafollicular cells
     • Cells around follicular cells that make calcitonin

3. Parathyroid glands

   • Small structures on the back of the thyroid gland

4. Chief cells & oxyphil cells

   • Chief cells make parathyroid hormone
   • PTH increases blood calcium