Thyroid gland is located on the ventral side of the neck region at the junction of the larynx and trachea. It is a bilobed gland, which secrets three hormones: thyroxine, triiodothyronine, and thyrocalcitonin (TCT) (or calcitonin).
Thyroxine and Triiodothyronine
The hormones thyroxine and triiodothyronine contain iodine and are iodinated amino acids. These are essential for growth, development, and metabolism. These influence blood pressure as well as pulse rate and also influence heat production at the time of oxidative metabolism in cells. Hyposecretion of these hormones results in cretinism (a disease characterized by slow metabolic rates, and retarded physical and mental development) in infants and myxedema (characterized by swollen face and hands, menorrhagia in women, and gynecomastia or complete loss of libido in males) in adults. Hyposecretion of these hormones also cause a disease called simple goitre, characterized by enlarged thyroid glands due to deficiency of iodine in diet. Hypersecretion of these hormones results in exophthalmic goitre (or Graves disease), characterized by excessive protrusion of eyeballs.
Thyrocalcitonin (TCT) or calcitonin
TCT lowers blood calcium and phosphate levels. It also promotes the formation of bone.
#Thyroid_gland
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