thyroid and parathyroid

• thyroid gland is endodermal in origin
• thyroid gland is composed of follicles and stromal cells
• follicular cells of the thyroid follicles secrete thyroxine (tetraiodothyronine) and triiodothyronine
• follicular cells are lined with columnar epithelium
• deficiency of iodine results in hypothyroidism and enlargement of the thyroid gland commonly called goitre
• hypothyroidism during pregnancy can lead to stunted growth, mental problems, low IQ, abnormal skin and deaf mutism in the growing baby
• hypothyroidism in adult women results in myxedema and may cause menstrual cycle to become irregular
• cancer of the thyroid gland results in increased rate of synthesis and secretion of thyroid hormones leading to hyperthyroidism
• exopthalmic goitre is characterized by enlargement of the thyroid gland, protrusion of eyeballs, increased basal metabolic rate, and weight loss
• exopthalmic goitre is also known as grave's disease
• thyroid hormones control metabolism of carbohydrates, fats and proteins
• metamorphosis of tadpole larva is regulated by thyroid hormones
• parafollicular cells of the thyroid gland secrete a hormone called thyrocalcitonin
• TCT decreases blood calcium levels and increases bone calcium levels
• four parathyroid glands are located on the posterior surface of the thyroid gland
• parathyroid hormones increase blood calcium levels and decrease bone calcium levels
• PTH stimulates reabsorption of Ca+2 ions from bones, renal tubules and digested food
• PTH is a hypercalcemic hormone
• PTH increases urinary excretion of phosphate ions
• thyroid gland is the largest endocrine gland