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7 Cards in this Set
- Front
- Back
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endochondral ossification |
-formation of bone within a cartilage model -Mesenchymal cells form a cartilaginous model (anlage) --> ossifies as none replaces cartilage -most bones of the body are formed by this process, especially long bones |
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first stage of endochondral growth |
-fetal hyaline cartilage model develops (8-12 weeks in utero) |
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2nd step in endochondral growth |
-cartilage model calcifies forming a bone collar around diaphysis of bone -cartilage cells become larger and lose their nutrients and die--creating a space inside the model -outer layer of cartialge is invaded by osteoblasts and becomes periosteum |
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3rd step in endochondral growth |
-primary ossification center forms in diaphysis (appear by 12th week fetal development) -capillaries and osteoblasts form a periosteal bud that extends into the cartilage shaft -calcified cartilage acts as template for new bone cells -starts at center of diaphysis and moves out in both directions |
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4th step in endochondral growth |
-secondary ossification centers appear (beginning around birth) -hyaline cartilage in epiphysis calcifies, replaced with bone cells -in the diaphysis --------medullary cavity forms in diaphysis and compact bone develops in diaphysis |
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5th step in endochondral growth |
-bone replaces most of the cartilage -cartilage present at articular surfaces and epiphyseal plates (to allow for growth) |
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6th step in endochondral growth |
-fusion of primary and secondary centers, growth in length stops -most epiphyseal plates fuse between 10-25 years |
