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30 Cards in this Set
- Front
- Back
- 3rd side (hint)
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what are the names of the two bone development mechanisms?
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intramembranous ossification and endochondral ossification
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where is bone laid down in intramembranous ossification?
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in place of preexisting mesenchyme, typically in a well-vascularized environment
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how is immature bone formed in intramembranous ossification?
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osteoblasts begin secreting osteoid which is subsequently mineralized into a poor-quality, immature woven bone.
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what occurs following formation of woven bone in intramembranous ossification?
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spicules of bone are replace through osteoclastic resorption and bone deposition by lemellar bone
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endochondral ossification involves the replacement of what? This is best exemplified in which bones?
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hyaline cartilage; long bones
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long bone growth begins with the formation of what structure? Through which form of ossification?
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bone collar; intramembranous
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None
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following formation of the bone collar in endochondral ossification, what happens to chondrocytes?
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they hypertrophy and die
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the release of what from hypertrophied chondrocytes in endochondral ossification causes calcification of the matrix?
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matrix vesicles
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how does calcified cartilage matrix stain in an H&E?
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very basophilic
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what is the name for the vasculature that penetrates the bone collar? What 3 types of cells are brought along?
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periosteal bud; osteoblasts, osteoclasts, osteoprogenitor cells
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None
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which cells are responsible for resorbing calcified cartilage in endochondral ossification?
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osteoclasts
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new bone matrix is laid down in endochondral ossification by which cells?
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osteoblasts
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the initial bone formed by osteoblasts in endochondral ossification is of what kind?
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immature (primary, woven)
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where is the secondary ossification center located in bone formation?
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at the episphyseal growth plate
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what is a primary spongiosa?
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a spicule of woven bone laid down in intramembranous ossification
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what is the site of intramembranous ossification in long bones? Of endochondral ossification?
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bone collar; epiphyseal growth plate
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what are the names of the 5 morphological zones of cartilage formation at the epiphyseal growth plate?
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resting, proliferating, maturing, hypertrophy and provisional calcification, primary spongiosa
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does growth in a bone stop completely with closure of epiphysis?
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no, growth of girth continues at bone collar
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during childhood, skeletal growth is stimulated by which hormone?
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growth hormone
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GH acts through which factors which are produced in liver and target skeletal tissues?
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somatomedins
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what is the name for the process by which spaces in trabeulcae are filled in to create compact bone?
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compaction
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if a primary spongiosa is destined to become cancellous bone, what must occur?
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only replacemet of woven bone with lamellar bone
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in which type of bone are primary osteons found?
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in woven bone which has just undergone compaction and is in the process of being replaced by lamellar bone to form secondary osteons
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during skeletogenesis, what is the name for the process of selective bone resorption and deposition?
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bone modeling
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what is the term used to descibe bone resorption and deposition which occurs throughout life, once skeletogenesis is complete? What is the name for the unit responsible for this process?
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bone remodeling; bone remodeling unit or bone multicellular unit (BMU)
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None
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where does bone remodeling occur in trabecular bone? In compact bone?
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on the surface; resorption cavities
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what are the 3 steps in the bone remodeling sequence? What is the name for this sequence?
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activation, resorption, formation; ARF sequence
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uncoupling of ARF sequence results in which common disorder?
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osteoporosis
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which form of ossification is used in repair of bone fractures? Which structure is formed in break?
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both forms; callus
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which is the only location of the body where bone growth is strictly intramembranous?
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skull
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