GENERAL HISTOLOGY

Detailed explanation-1: -What is calcitonin? 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: -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.

Detailed explanation-3: -Calcitonin is involved in helping to regulate levels of calcium and phosphate in the blood, opposing the action of parathyroid hormone. This means that it acts to reduce calcium levels in the blood.

Detailed explanation-4: -Calcitonin is a 32 amino acid hormone secreted by the C-cells of the thyroid gland. Calcitonin has been preserved during the transition from ocean-based life to land dwellers and is phylogenetically older than parathyroid hormone.