AVS-4160 Lecture Notes - Lecture 22: Osteon, Bone Density, Medullary Cavity
29 Nov 2016
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Document Summary
Radiographic bone aluminum equivalence is used to measure bone thickness. It looks like a stairstep and is clipped to the radiograph film. Acute exercise over a hard surface increases bone density. Periosteum gives ligaments something to bind to. Osteoprogenitor cells are located between the periosteum and the bone. Medullary canal: the inner lumen of the bone, where the marrow is, the thickness of the medullary cavity is related to the animal"s body weight. It becomes larger from side-to- side than from front-to-back. Bone gets stronger by developing more matrix both collagenous and mineralized. Astronauts have to do resistance exercises to improve bone strength despite the lack of gravity. A broken bone, once healed, is stronger than it was before. Exercise increases mineralization and breaking strength due to the change to oval shape. When bone is in disuse, the collagen is the first portion that degrades. Loss of collagen makes the bone brittle. Increased remodeling results in net bone density loss.
