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26 Cards in this Set
- Front
- Back
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Does cartilage become bone?
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no it is replaced by bone
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How do bones grow?
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by apposition, not interstial growth
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T or F - bone does not require a good blood supply
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F
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What is intramembranous bone formation also called?
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direct osification
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Osteoprogenator cells are derived from what?
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mesenchymal cells
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In intramembranous Ossification, osteoprogenator cells become ___________ which begin producing what?
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- osteoblasts
- bony spicules |
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What remodels bone after intramembrous bone formation?
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Osteoblasts and osteoclasts
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What type of ossification primarily occurs in the skull?
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inramembranous
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Endochondrial ossification is also called what?
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indirect ossification
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What type of ossification uses hyline cartilage as a model for bone formation?
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endochondrial
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What forms along the diaphasis of the bone in endochondrial formation?
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a bone collar
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In endochondrial bone formation where does calcification begin?
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in the diaphysis
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What forms the marrow cavity in endochondrial formation?
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when blood vessels and connective tissue invade the calcified cartilage
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Where are the secondary centers of ossification in endochondrial bone formation?
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in the epiphysis
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What remains between ephysis and diaphysis in endochondrial bone formation?
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hyline cartilage
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Where is calcified cartilage replace by bone?
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in the metaphysis
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What are the zones of cartilage in the ephiphysial discs? starting with layer furthest from the metaphysis (closest to epiphysis).
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Quiscent zone
- chondrocytes not actively dividing or producing matrix Proliferative zone - cells larger than Quiscent zone; they undergo mitosis and line up in distinct columns Zone of maturation or hypertrophy - cells become very large and their cells fill with glycogen; matrix compresses into narrow bands; cells commit apitosis Zone of calcification - cells die and cartilage is calcified Zone of ossification - Bone is layed down on spicules of calcified cartilage |
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When does the epiphysial disc become calcified?
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in a persons early 20's
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Describe bone growth in diameter
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periosteal osteoblasts lay down bone appositionaly increasing its diameter.
Endostial osteoclasts resorb bone increasing the marrow cavity. |
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Describe primary bone. What else is it called?
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also called immature or woven bone. abundant osteocytes and irregular collagen fibers
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Describe secondary or mature bone
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also called lamellar bone. Osteocytes less abundant and more evenly space compare to immature bone. Collagen fibers are parallel to given lamellae
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Where does bone remodeling take place?
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along lines of stress
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Decribe the remodeling process
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resorbtion by osteoclasts. New bone laid down by osteoblasts. Osteoblasts become embedded in matrix and become osteocytes
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What are the stages of bone repair?
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1)localized hemorrhage, clot formation
2)clean-up by macrophages 3) proliferation of osteoprogenitor cells 4) production of immature bone (via endochondral and intramembranous ossification) 5) broken ends of bone united by trabeculae, forming callus 6) callus area remodeled along lines of stress |
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What can bone loss be due to?
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decreased calcium intake
decrease in sex steroid levels, especially estrogen decreased exercise consumption of calcium-depleting substances |
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How do you prevent osteoporosis?
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1) increase peak bone mass in children
2) regular exercise 3) adequate calcium intake 4) hormone replacement theropy of use of biphosphates 5) avoid calcium depletling substances |
