The bone is made up of the associated cells and matrix.
The matrix includes ossein, calcium phosphate and other inorganic and organic components.
Since Calcium is one of the important constituent, bone needs a proper supply of calcium ions from the blood vessels. The uptake and release of calcium depends on the hormones secreted from the thyroid and parathyroid gland.
When more calcium is lost from the bone, this results in osteoporosis. This is due to hypersecretion of parathyroid hormone or due to hyposecretion of calcitonin( Hormone from thyroid gland).
Higher concentration of calcium in blood has little effect on bone but can cause calcification of other soft tissues.