MEDICAL PHYSIOLOGY

Detailed explanation-1: -Calcitonin is secreted by the parafollicular cells of the thyroid gland. This hormone opposes the action of the parathyroid glands by reducing the calcium level in the blood. If blood calcium becomes too high, calcitonin is secreted until calcium ion levels decrease to normal.

Detailed explanation-2: -What stimulates calcitonin release? Your thyroid releases calcitonin based on the level of calcium in your blood. When your blood calcium levels increase, your thyroid releases calcitonin in higher quantities. When blood calcium levels decrease, your thyroid decreases the amount of calcitonin it releases.

Detailed explanation-3: -The parathyroid glands release parathyroid hormone (PTH) in response to a decrease in serum calcium. PTH acts on the kidneys to increase calcium reabsorption in the ascending loop of Henle, the distal convoluted tubule, and the collecting duct.

Detailed explanation-4: -First, calcitonin opposes osteoclasts, cells that break down bone in the body. Bones contain calcium, which gets released into the bloodstream when they are broken down by osteoclasts. Meanwhile, calcitonin prevents excess amounts of calcium from deteriorating bones to enter the bloodstream.

Detailed explanation-5: -When the calcium level is high in the bloodstream, the thyroid gland releases calcitonin. Calcitonin slows down the activity of the osteoclasts found in bone. This decreases blood calcium levels. When calcium levels decrease, this stimulates the parathyroid gland to release parathyroid hormone.