OSTEOPOROSIS AND ROLE RANKL-RANK-OPG SYSTEM AND NOTCH SIGNALING PATHWAY IN BONE DEVELOPMENT AND REMODELING Physiological bone remodeling is a highly coordinated process responsible for bone resorption and formation and is necessary to repair damaged bone and maintain mineral homeostasis. In addition to the traditional bone cells, osteoblasts, osteoclasts and osteocytes that are necessary for bone remodeling biological active factors have also been implicated in bone disorders. This review discussed in detail are the cellular and molecular mechanisms of bone remodeling, including events that...