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64 Cards in this Set
- Front
- Back
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adult humans have how many bones
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206 bones
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humans are born with
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300 bones
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ligaments
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link bone to bone
stabilize joints limit range of motion dense connective tissue (DCT) |
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largest bone
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femor
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smallest bone
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ear bones
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main roles of skeletal system
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support and movement
protection blood cell production mineral storage lipid storage (energy) |
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protection
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bones surround vulnerable internal organs like brain, spinal cord and heart
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blood cell production (skeletal system)
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all types of blood cells are made in the bone
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about how much percentage of calcium in your bones
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99%
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minerals in bones
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calcium, phosphorus, magnesium
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long bones
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longer than wide
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short bones
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roughly equal dimensions
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flat bones
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thin and broad
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sesamoid bones
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-may develop within tendons for protection against friction (response to stress)
-most only few mm |
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irregular bones
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complex shape
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5 basic bone shapes
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long bones
short bones flat bones sesamoid bones irregular bones |
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skeleton is % of compact bone
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80%
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epiphysis
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end region
covered with articular cartilage (made of hyaline cartilage) spongy bone trabeculae |
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inside bone
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spongy bone
main location of blood cell production (red marrow) |
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trabeculae
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bony plates (reduces weight)
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diaphysis
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-middle region
-compact bone -lipid storage area (yellow marro) medullary cavity endosteum nutrient forament |
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yellow marrow
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store lipids
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medullary cavity
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hollow chamber with in diaphysis contains yellow marrow
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endosteum
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inside lining containing bone-forming cells
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nutrient foramen
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holes for allowing nutrient artery and vein passage into bone
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periosteum
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-2 layer membrane around bone
-house nerves and blood vessels -provides attachment sites for tendons/ligaments -has pain sensors -protection |
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Bone (osseous tissue)
MATRIX |
25% WATER
25% collagen fibers (flexibility) 50% crystallized mineral salts (hardness) |
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crystallized mineral salts in osseous tissue
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mostly calcium phosphate, calcium carbonate
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OSTEON
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FUNCTIONAL UNIT arranged around central canal
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central canal
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main passage for blood vessels and nerves
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osteocyte
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bone cell
maintains living bone tissue makes repairs does not divide |
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lacunae
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lacuna
cavities that hold osteocytes |
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canaliculi
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tiny branches that radiate out from central canal
-bring oxygen/nutrients to all osteocytes |
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osteoblasts
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-bone building cells
-made in periosteum -create bony matrix around themselves using calcium slats (deposition) -eventually, they are trapped as osteocytes |
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osteoclasts
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-release acids to dissolve bone matrix (resorption)
-results: stored calcium is released |
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bone development
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intramembranous bones (some)
endochondral bones (most) |
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intramembranous bones
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develop directly from layers of connective tissue
-bones of skull |
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endochondral bones
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-within cartilage
-develop from hyaline cartilage |
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ossification
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process of changing cartilage to bone
-begins at 8 weeks -not completed till about 20-25 yrs old |
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epiphyseal plate
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is visible until ossification is complete
region of mitotic activity |
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epiphyseal plate divided into 4 zones
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-zone of resting cartilage
-zone of proliferating cartilage -zone of hypertrophic cartilage -zone of calcified cartilage |
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zone of proliferating cartilage
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-large chondrocytes stacked like coins
-divide and secret extracellular matrix |
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zone of hypertrophic cartilage
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-large maturing chrondrocytes arranged in columns/growing larger
-cessation of mitosis |
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zone of calcified cartilage
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-thin layer of dead chrondrocytes
-matrix calcified -becomes part of diaphysis |
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growth rate affected by
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genes
nutrition minerals vitamins D, C, A hormones activity |
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minerals needed to build and maintain matrix
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calcium
phosphorus |
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vitamin d
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-needed for calcium absorption
-cant build strong bones with out it |
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vitamin c
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-needed to make collagin with out bones will be abnormally slender and fragile
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vitamin a
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necessary for osteoblasts and osteoclasts normal functions
-deficency may retard bone development |
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growth hormone (GH)
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from gland in brain/ stimulates mitosis, especially in bone and musle tissue
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Pituitary gigantism
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too much growth hormone-very tall
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pituitary dwarfism
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too little growth hormone- very short
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exercise (physical stress) with it
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with it: bones thicken and strengthen (hypertrophy)
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exercise (physical stress) without it:
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without it: bones thin and weaken (atrophy)
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bone remodeling
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-continual process of turnover (resorption and deposition)
-about 5% of your skeleton is remodeled every year -allows for minor changes to be made based on use and lifestyle changes |
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fractures
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oblique
transverse comminuted spiral compound greenstick |
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oblique
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occurs at an angle (other than 90%)
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transverse
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occurs at a 90%
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comminuted
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complete break with fragments
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spiral
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caused by excessive twisting
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compound
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break that exposes bone outside of skin (high risk of infection)
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greenstick
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incomplete break
occurs in children whose bones are not yet ossified |
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as you age (bone)
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resorption outpaces deposition
collagen productions slows bones gradually weaken and become more brittle osteoporosis |
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osteoporosis
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gradual bone loss
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