There are at least three specialized bone cells that are responsible for the synthesis, modeling, and remodeling of bone. Specialized osteocytes affect the constant modeling and remodeling of bone. The osteoblasts secrete three chains that make up Type one collagen to form osteoid, which is the uncalcified precursor to bone. Osteocytes are thought to be quiet osteoblasts. They appear to communicate with one another and with the surface osteoblasts through the bone canaliculi.
Osteoclasts destroy bone as part of the overall continual remodeling process.
Osteoclasts reabsorb the existing bone while the new bone is formed by osteoblasts. There are many factors that affect bone metabolism. It is affected by age, activity, dietary minerals, vitamin D, sex hormones, thyroid metabolism, parathyroid hormones, and many other factors. The calcium intake is thought to influence the bone loss due to aging. However what is not clear is its effects greater on the achievement of peak bone mass or on the moderation of subsequent bone loss.