Bone Diseases

Prof Claus C. Gluer and Prof Marius KraenzlinImagine our body without bones and joints. Bones constitute about 15% of total body weight. Bone is a dynamic structure in a living body. It consists of multiple layers of fibers around which minerals such as calcium are deposited in crystalline form. The hardness and rigidity of bones is due to minerals whereas resilience and toughness is due to fibers. Remodeling of bones (turnover) continues throughout life and is brought about by various bone cells. The remodeling cycle of bone is an orderly process initiated by osteoclasts (cells that destroy bone and form a 'pit') and followed by formation of new bone by cells known as osteoblasts. Bone formation and resorption are in dynamic equilibrium. Calcium is an essential constituent of bones. Vitamin D, formed under the skin on exposure to sunlight, maintains calcium balance and is important in bone formation.