MICROANATOMY

Detailed explanation-1: -Calcitonin is a hormone that your thyroid gland makes and releases to help regulate calcium levels in your blood by decreasing it. Calcitonin opposes the actions of the parathyroid hormone, which is a hormone that increases your blood calcium levels.

Detailed explanation-2: -Calcium homeostasis is maintained by actions of hormones that regulate calcium transport in the gut, kidneys, and bone. The 3 primary hormones are parathyroid hormone (PTH) 1, 25-dihydroxyvitamin D-3 (Vitamin D3), and calcitonin.

Detailed explanation-3: -Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low. It does this through its actions on the kidneys, bones and intestine: Bones – parathyroid hormone stimulates the release of calcium from large calcium stores in the bones into the bloodstream.

Detailed explanation-4: -Parathyroid hormone (PTH) levels are mainly controlled by a feedback loop of calcium levels in your blood to your parathyroid glands. In other words, low calcium levels in your blood stimulate parathyroid hormone release, whereas high calcium levels in your blood prevent your glands from releasing parathyroid hormone.

Detailed explanation-5: -Parathyroid hormone is directly involved in the bones, kidneys, and small intestine. In the bones, PTH stimulates the release of calcium in an indirect process through osteoclasts which ultimately leads to the resorption of the bones.