BISC 101 Chapter Notes -Bone Resorption, Collagen, Manganese
20 Oct 2012
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Document Summary
Ossification (ossification) process by which bone forms that occurs in four principal situations: Initial bone formation in an embryo and fetus. The embryonic skeleton, initially composed of mesenchyme, is where cartilage formation and ossification occur during the 6th week of embryonic development. Two types of formation both replace pre-existing ct with bone; no differences in mature bones. Intramembranous ossification bone forms directly within mesenchyme: endochondral ossification bone forms within hyaline cartilage that develops from mesenchyme. The simpler process that forms the skull, facial bones, mandible, medial part of the clavicle, and fontanels. At the site where bone will develop, chemical messages cause the mesenchymal cells to cluster together and differentiate ossification center. Osteoblasts secrete the organic matrix of bone until they are surrounded by it. The cells, now osteocytes, lie in lacunae and extend their narrow cytoplasmic processes into caniculi that radiate in all directions. Within a few days, calcium and other mineral salts are deposited.
