Question

Briefly explain the structure of thyroid gland.

Answer 1

The thyroid gland is butterfly-shaped, bilobed situated below the larynx on each side of the upper trachea. The two lobes are connected by a median tissue mass called isthmus. Each lobe is made up of many lobules. The lobules consist of follicles called acini. Each acinus is lined with glandular, cuboidal, or squamous epithelial cells.

The lumen of acini is filled with colloid, a thick glycoprotein mixture consisting of thyroglobulin molecules. The thyroid gland secretes Tri-iodothyronine (T₃) and tetra-iodothyronine (T₄) or thyroxine hormones. These are concerned with metabolism.

                          Structure of Thyroid gland