The osteoblasts form new lamellar bone upon the recently exposed surface of the mineralized matrix.

The osteoclast removes the mineralized matrix and collagen by secreting enzymes.

At this point, the mineralized matrix is penetrated by channels, each containing a microvessel and numerous osteoblasts.

They cease to generate osteoid and mineralized matrix, and instead act in a paracrine manner on active osteoblasts.

Stro-1 +cells cultured in an osteogenic medium exhibit three markers of differentiated bone: AP; 1,25-dihydroxyvitamin-D 3 -dependent induction of osteocalcin; and a mineralized matrix (hydroxyapatite) [ 36, 37].

Each osteon has concentric layers of mineralized matrix, called concentric lamellae, which are deposited around a central canal, also known as the Haversian canal, each containing a blood and nerve supply.