Figure 2:

Bone remodeling.

(A) Microscopic views of bone-forming osteoblasts (toluidine blue staining) as well as bone-resorbing osteoclasts (trichrome Goldner staining). Osteocytes (bottom row) are connected via canalicular extensions and are able to sense mechanical strain to signal osteoblasts and osteoclasts. (B) Simplified bone remodeling scheme demonstrates the interplay between the bone cells. Ob, Osteoblasts; Oc, osteoclasts; Ot, osteocytes; (+), stimulation; (–), inhibition. Osteoporosis drugs and their targets are in red.