Osteoblasts

Osteoblasts are bone-forming cells of mesenchymal origin that synthesize and mineralize bone matrix by secreting type I collagen and regulators of hydroxyapatite deposition. They mature into osteocytes embedded within bone or into bone-lining cells, and they control osteoclast formation through RANKL and OPG signaling. Their declining activity with age contributes to skeletal fragility.