ABSTRACT
Bone is a dynamic organ that constantly undergoes remodeling. Bone remodeling encapsulates two opposing actions: bone resorption and bone formation. These two processes are combined in time and space at the level of basic multicellular units (BMUs). Bone resorption consists of the actions of osteoclasts and involves the dissolution of bone mineral to its components. In immediate succession, osteoblasts synthesize bone matrix and mineralize the previously created void. Various systemic hormones (e.g., parathyroid hormone, vitamin D, steroid hormones) or locally acting cytokines and growth factors regulate the balance between bone resorption and formation. Under physiologic conditions, this process is completed in a period of 3–6 months. Disturbance of this process, with a preponderance of resorption, can lead to osteoporosis.
