Osteoprogenitor Cells
Osteoprogenitor cells are heavily involved in the growth and repairing of bones. They originate from stem cells, and are created by progenitor cells. Located in the inner cellular layer of the periosteum and bone marrow, these immature cells mature into Osteoblasts. They start as a mesenchymal cell in the marrow, then grows from a progenitor cell to an osteoprogenitor cell.
Osteoblast cells
Osteoblast cells are responsible for bone formation. They only contain one nucleus, and function by secreting a substance called osteoid, aka bone matrix. Its mineralized with calcium and phosphate. found in the inner and outer surfaces of bones. Osteoblasts are involved in making new bone in a process called osteogenesis. Osteoblasts are able to convert into Osteocytes.
Osteoclast Cells
Osteoclast cells are responsible for dissolving bone tissue in a process also known as resorption. White blood cells usually collide to form these cells. theyre quite large with multiple nuclei, some contain up to 200, although its more likely to have 5 to 20. Osteoclasts are the "mediators" for the continuous destruction of the bone. They're located in small depressions of the bone's surface, called Howship lacunae, or in the endosteum.
Osteocyte cells
Osteocyte cells have a star-shaped appearance. They're derived from Osteoblasts, essentially Osteoblasts surrounded by the products they secreted. These cells are typically long lived, living as long as the bone they occupy in does. They have long "branches" that reach out from the cell body & communicate with neighboring Osteocytes, usually to respond to even the slightest deformations caused by muscular activity. Osteocytes play an important role in maintaining Calcium levels in our body fluids, especially if calcium levels drop.