Parathyroid Hormone (PTH): A hormone secreted by the parathyroid glands that plays a central role in regulating calcium levels in the body by stimulating the release of calcium from bone, increasing calcium absorption in the intestines, and promoting calcium reabsorption in the kidneys.
Calcitonin:A hormone secreted by the thyroid gland that helps lower blood calcium levels by inhibiting the activity of osteoclasts, the cells responsible for breaking down bone, and promoting the deposition of calcium into bone.
Vitamin D:A fat-soluble vitamin that is essential for the absorption of calcium from the intestines and the regulation of calcium homeostasis. It is produced in the skin when exposed to sunlight and can also be obtained through dietary sources.