Two lobes located on either side of trachea. These lobes are connected with thin flaps of connective tissue.
Thyroid gland is composed of follicles and stromal tissues.
Follicular cells synthesize two hormones, T4 and T3.
Iodine is essential for normal hormone synthesis in the thyroid.
Hypothyroidism – deficiency of iodine leads to enlargement of thyroid gland (causes goiter).
Hyperthyroidism – high levels of thyroid in body.
Role of thyroid hormone – regulation of basal metabolic rate, process of RBC formation, control the metabolism of carbohydrates, proteins and fats, maintenance of water and electrolyte balance, secrete protein hormone (called thyrocalcitonin which regulates blood calcium levels.