Bone Marrow - * Four types of cells * osteoprogenitor...

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Skeletal System Bone Marrow * Soft tissue that occupies the medullary cavity * red bone marrow- hemopoietic tissue (blood producing) * in the child most of the bone marrow is red * yellow bone marrow- in adults most of the medullary cavities are replaced with yellow bone marrow. * red marrow limited to vertebrae, ribs. sternum, part of the pelvic girdle, and the proximal ends of the humerous and femur * gelatinous marrow- by old age most of the yellow marrow is replaced by this reddish jell. Periosteum * Composed of * tough outer fibrous layer of collagen * some fibers are continuous with the tendons * some fibers penetrate into the bone matrix as perforating (Sharpey) fibers * inner osteogenic layer of bone-forming cells (osteogenic cells) Bone Histology * Ossious tissue contains a lot of matrix material (intercellular substance) * consist of inorganic components (mineral salts) which makes bone hard. * organic material (mostly collagen fibers) which gives bone its strength.
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Unformatted text preview: * Four types of cells * osteoprogenitor (osteogenic) cells are precursor bone cells that undergo mitosis to become osteoblast. * found in the periosteum, endosteum, and canals in bone that contain blood vessels. * osteoblast- the cells that form bone but do not have the ability to divide by mitosis. * Are found on the surface of bone * they initially form collagen and other organic compounds to build bone * osteocyte- are mature bone cells derived from osteoblast that have secreted bone tissue around themselves. * They maintain healthy bone * do not undergo mitosis * osteoclast- function in bone destruction (resorption) which is important in the development, growth, maintenance, and repair of bone. * Are multicellular cells that secrete enzymes that breakdown bone Osteoblast Osteoclast...
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