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42 Cards in this Set
- Front
- Back
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Osteogenic cells |
Mitotically active stem cells found in membranous periosteum and endosteum |
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Osteoblasts |
Mitotically active bone forming cells that secrete the bone matrix |
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Osteocytes |
Mature bone cells that occupy spaces that conform to their shape; monitor and maintain bone matrix; act as stress or strain sensors and respond to mechanical stimuli |
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Bone lining cells |
Flat cells found on bone surfaces where bone remodeling is not going on; periosteal=external bone surface, endosteal=internal bone surface |
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Osteoclasts |
Giant multinucleate cells located at sites of bone resorption (breakdown); undergo apoptosis when resorption of bone is done |
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Osteon or haversian system |
Structural unit of compact bone; an elongated cylinder oriented parallel to the long axis of a bone; tiny weight-bearing pillars; lamella (layer) is a matrix tube |
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Central or Haversian canal |
Runs through the core of each osteon, containing small blood vessels and nerve fibers that serve the osteon's cells |
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Perforating or Volkmann's canals |
Lie at right angles to the long axis of the bone and connect the blood and nerve supply of the medullary cavity to the central canals; not surrounded by concentric lamellae unlike central canals; lined with endosteum |
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Canaliculi |
Hairlike canals that connect the lacunae to each other and to the central canal; allow osteocytes to communicate |
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Intramembranous ossification (1 of 2 ways to generate bone) |
Bone develops from a fibrous membrane and bone is called membrane bone, forms cranial bones and clavicles; 1)ossification centers appear in the fibrous connective tissue membrane 2) osteoid is secreted within the fibrous membrane and calcifies 3) woven bone and periosteum form 4) lamellar bone replaces woven bone, just deep to the periosteum; red marrow appears |
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Endochondral ossification ( 2 of 2 ways to generate bone) |
Forms all bones below skill except clavicles; uses hyaline cartilage "bones" formed earlier as models for bone construction; steps in a long bone: 1) bone collar forms around the diaphysis of the hyaline cartilage model 2) cartilage in the center of the diaphysis calcifies and then develops cavities 3) the periosteal bud invades the internal cavities and spongy bone forms 4) the diaphysis elongates and a medullary cavity forms 5) the epiphyses ossify; hyaline cartilage remains only in epiphyseal plates and articular cartilages |
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Hormone regulation of Bone Growth |
Growth hormone is most important hormone during infancy and childhood, released by anterior pituitary gland; thyroid hormones modulate activity of growth hormone |
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Role of sex hormones |
Initially promote growth spurt in adolescents but later induce epiphyseal closure, ending longitudinal bone growth |
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Bone remodeling |
Bone deposit and bone resorption occurs at the surface of both the periosteum and the endosteum; "packets" of adjacent osteoblasts and osteoclasts called remodeling units coordinate bone remodeling |
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Synarthroses |
Immovable joints |
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Amphiarthroses |
Slightly movable joints |
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Diarthroses |
Freely movable joints |
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Synovial joints |
Bones separated by fluid-filled joint cavity; diarthrotic; includes almost all limb joints |
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PTH |
Increases vitamin D conversion, increases reabsorption, increases activity of osteoclasts; released when blood calcium is low, it is released and causes osteoclasts to resorb bone and release calcium into the blood |
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Lacunae |
Gaps in bone matrix that contain osteocytes |
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Bone's response to mechanical stress (muscle pull) |
Long bones are thickest midway along the diaphysis because of mechanical stressors |
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Wolff's Law |
A bone grows or remodels in response to the demands placed on it |
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Steps of fracture repair |
1) a hematoma (mass of clotted blood) forms 2) fibrocartilaginous callus forms 3) bony callus forms 4) bone remodeling occurs |
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Reduction |
The realignment of the broken bone ends |
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Which epidermal cell is most numerous? - keratinocytes - melanocytes - dendritic cell - tactile cell |
Keratinocytes |
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Which cell functions as part of the immune system? |
Dendritic cell |
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The epidermis provides a physical barrier b/c of presence of |
Keratin |
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Sensations of touch and pressure are picked up by receptors located in |
Dermis |
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Skin surface markings that reflect points of tight dermal attachment to underlying tissues |
Flexure lines |
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Arrector pili muscles |
Cause hair to stand up straight |
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This type of sweat gland includes protein and lipid substances that become odoriferous b/c of bacteria |
Apocrine gland |
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Rule of nines is helpful in |
Diagnosing skin cancer |
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Organic portion of matrix doesn't provide: |
Hardness |
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Flat bones of skull develop from |
Fibrous connective tissue |
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Bone remodeling in adults is mainly regulated by |
Mechanical stress and PTH |
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Where in epiphyseal plate are dividing cartilage cells located |
Between resting and hypertrophic zone |
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Fracture type where bone ends are incompletely separated |
Greenstick |
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Disorder where bones are porous and thin but bone composition is normal |
Osteoporosis |
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Suture mobility |
Synarthrosis |
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Gomphosis mobility |
Synarthrosis |
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Synchondrosis mobility |
Synarthrosis |
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Symphysis |
Amphiarthrosis |
