Osteogenic cells are located in the deep layers of the periosteum and the marrow. They develop into osteoblasts. 

Osteoblasts are located in the growing portions of bone, including the periosteum and the marrow. They play a key role in bone formation. 

Osteocytes are found entrapped in the matrix. They secrete enzymes that help maintain the mineral concentration of the matrix. 

Osteoclasts are located at bone surfaces and at sites of injured, old or unneeded bone. They are involved in bone resorption.