What gland affects bone density by controlling the level of calcium ions?

The parathyroid gland affects bone density by regulating the levels of calcium ions in the bloodstream. It secretes parathyroid hormone (PTH), which increases calcium levels by promoting the release of calcium from bones, enhancing calcium reabsorption in the kidneys, and stimulating the activation of vitamin D to improve intestinal calcium absorption. By maintaining calcium homeostasis, the parathyroid gland plays a crucial role in bone health and density.