L. Shi, A. Niedzwiecki, M. Rath
Journal of Cellular Medicine and Natural Health, July 2019
Bone is a specialized connective tissue and its formation involves many steps and stages. It is a dynamic tissue that responds to many internal and external factors and adapts to changing functional conditions. Bone is composed of various types of cells and collagenous extracellular organic matrix, which is predominantly type I collagen (85–95%) that becomes hardened by the deposition of calcium hydroxyapatite. Bone also contains various proteins and proteoglycans, which are specific to bone and dental hard connective tissues. Healthy bone metabolism depends on the proper function of different types of bone cells, such as osteoclasts which resorb (dissolve) the bone, osteoblasts that build the bone, osteocytes that help maintain bone, and lining cells that cover the surface of the bone. Osteoblasts activate bone growth and differentiate to osteocytes during bone formation. The osteocytes respond to mechanical stress and play an important role in bone remodeling.