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Osteoblasts are bone-forming cells that descend from osteoprogenitor cells. They form a protein mixture known as osteoid, which mineralizes to become bone. Osteoid is primarily composed of Type I collagen.Osteoblasts also manufacture hormones, such as prostaglandins, to act on the bone itself.steocytes: Osteocytes are mature bone cells that originate from osteoblasts, which have migrated into and become trapped and surrounded by bone matrix, produced by themselves. The spaces they occupy are known as lacunae.
During bone formation, the surface layer of osteoblasts consists of cuboidal cells, called active osteoblasts. When the bone-forming unit is not actively synthesizing bone, the surface osteoblasts are flattened and are called inactive osteoblasts. Osteocytes remain alive and are connected by cell processes to a surface layer of osteoblasts. Osteocytes have important functions in skeletal maintenance. Osteoclasts. Osteoclasts break down bone tissue, and along with osteoblasts and osteocytes form the structural components of bone.