22. Metabolic bone diseases

The skeleton clearly has a large number of mechanical functions. It protects vital structures, and muscles and tendons are firmly attached to the bone. Our hard bones also form a very active organ. Bone is constantly broken down and rebuilt. Approximately 10 % of bone tissue is renewed each year. The bone is also an important reservoir of minerals. A large number of endocrine factors are involved in the control of bone remodeling. The calcium and phosphate balance is partly regulated by the bone, and diseases that affect this balance also have an indirect effect on the shape and firmness of the bone.