Briefly explain the structure of thyroid gland

Explanation

Structure of thyroid gland :
Thyroid gland is the largest endocrine gland in the body.
1. It is butterfly shaped bilobed gland located below the larynx on either side of upper trachea
2. The two lateral lobes are connected by a median tissue mass called isthmus
3. Each lobe is made up of many lobules.The lobules consist of follicles called acini
4. Each acinus is lined with glandular cuboidal or squamous epithelial cells. The lumen of acimus is filled with colloid, a thick glycoprotein mixture consisting of thyroglobulin molecules
5. The folicular cells of thyroid gland secretes two hormones namely tri-iodothyronine `( T_3) ` and thyroxine or tetra-iodothyronine ` ( T_4) `
6. The parafollicular cells or 'C' cells of thyroid gland secrete a hormone called thyrocalcitonin .lodine is essential for the normal synthesis of thyroid hormones.