Bone remodeling is mediated by bone-forming cells called osteoblasts and bone-degrading cells called osteoclasts. Calcium and vitamin D are important molecular components that are inputs to osteoblasts to create new bone mass. In health, there is homeostasis between the formation of new bone and degradation of old bone. A diagram of an osteoblast and bone production in terms of inputs and outputs of the cell can be drawn. Secondly, the levels of extracellular calcium, vitamin D, and bone production would be affected in the case of an osteoblastic disease where these cells are dying. Assuming that osteoclasts (bone-degrading cells) maintain consistent function in both model systems of health and disease.
