Tuesday, July 9, 2013

Bone Resorption

Bone resorption is loss of bone tissue induced either by physiological or pathologic means. Although it can lead to bone mass loss and weakening of bone structures, when it is caused by a disease, resorption in a healthy person is an important physiological process, by which calcium levels in the circulating blood are maintained. The cells responsible of breaking down bone to be reabsorbed in the blood are the osteoclasts, which are large multinucleate cells that are found in growing bones.

Bone resorption occurs in the upper or lower maxillaries (jaws), when a tooth is pulled out; after menopause; in rheumatoid arthritis; in physical inactivity (sedentarism) and when a human being is away from the effects of the Earth's gravity (orbiting astronauts); in these two latter cases the bone resorption is triggered by atrophy due to muscle inactivity.