Term
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Definition
| refers to the formation and development of the cells of the blood |
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Term
| What minerals do the bones store? |
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Definition
| calcium phosphate salts (hydroxyapatite) |
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Term
| What kind of collagen is in bone? |
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Definition
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Term
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Definition
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Term
| What is the weight distribution of the bones between collagen and minerals? |
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Definition
| 40% collagen, 60% minerals (calcium phosphate salts) |
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Term
| What are the 3 types of bones |
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Definition
| Cortical/Compact bone, Trabecular or cancellous or spongy bone, Woven bone |
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Term
| What is the purpose for hard and soft parts of bones? |
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Definition
| strength to resist heavy weight, and cushion to accomodate heavy weight. |
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Term
| Where is cortical bone found in the body? |
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Definition
| foudn in the shaft of long bones. forms outer shell around spongy bone at the end of joints and vertebrae |
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Term
| What percent of the skeleton is formed by cortical bone? |
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Definition
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Term
| What makes up the haversian system or oteon in the cortical bone and what does it contain? |
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Definition
| Lamella forming concenteric rings forming the haversian canal which contains capillaries and nerve fibers. |
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Term
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Definition
| hollows within matrix where osteoblasts are encased |
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Term
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Definition
| tiny canals that interconnect lacunae |
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Term
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Definition
| penetrates bones perpendicularly & communicates with vessels in the Haversian canals |
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Term
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Definition
| Less dense and more porosity. Found in the end of long bones, vertebrae and flat bones like pelvis. 20% of skeleton. Lamellae present but do not form haversian system. trabeculae laid down in proportion to amount of mechanical stress pere Wolff's law. |
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Term
| T/F. Osteocytes, lacunae, and canaliculi in trabecular bone DO NOT resemble those in compact bone. |
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Definition
| False. They do resemble compact bone. |
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Term
| When is woven bone mostly present? |
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Definition
| Forms embryonic skeleton, largely absent from normal bone after age 4 yrs. can be seen in fracture callus in both children and adults. |
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Term
| T/F. Woven bone does not contain lamellae, but rathere has a relatively disorganized array of collagen with irregular mineralization pattern. |
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| portion of a long bone bbetween the epiphyses and the diaphysis |
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Term
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Definition
| Is fibrous connective tissue that is wrapped around the bone in all places exept at joints. Nociceptive nerves. Provides nourishment. Osteogenic cells & osteoblasts, vital role in healing. insertion point for tendons and ligaments. |
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Term
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Definition
| Covers the trabeculae of spongy bone. |
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Term
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Definition
| covers the trabeculae of spongy bone, lines medullary cavity, contains osteogenic cells & osteoblasts. |
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Term
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Definition
| found mainly in the flat bones such as hip bone, skull, ribs, vertebrae, and sholder blades, cancellous bone at proximal ends of long bones femur and humerus. |
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Term
| In what kind of marrow are red blood cells, platelets and most white blodd cells produced? |
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Definition
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Term
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Definition
| foudn in the hollow interior of the middle portion of long bones. has high fat cells, which cause the marrow to appear in yellow. |
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Term
| Stem cells in bone marrows |
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Definition
| Hematopoietic stem cells, and mesnchymal cells are located in the bone marrow. |
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Term
| What kind of bone marrow is used for bone marrow transplants? |
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Definition
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Term
| What kind of stem cells have the capability to differentiate into osteoblasts, chondrocytes, myocytes, and many other types of cells. |
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Definition
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Term
| How do osteoclasts originate? |
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Definition
| Formed by the fusion of mononuclear cells derived from hematopoietic stem cells in marrow. |
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Term
| Where are osteoclasts typically located in the bones and what is it's function? |
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Definition
| Large motile, multinucleated cell in resorption bay. Responsible for bone resorptio. Adhere to bone surface via integrins. |
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Term
| How are Osteoblasts formed |
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Definition
| They are derived from mesenchymal precursor cells in the bone marrow. |
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Term
| What are the primary functions of osteoblasts? |
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Definition
| produce new bone "osteoid". Forming matrix-> type 1 collagen. making cell lines after finishing filling cavity during remodeling process. control Ca2+ and mineral deposition. |
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Term
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Definition
| Resides in lacunae. have thin processes, which exteend from lacunae into small channels in bone, called the canaliculi. sense pressure and cracks. direct osteoclasts. |
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Term
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Definition
| Derived from embryonic mesenchyme; capable of differentiating into osteoblasts. dound in eendosteum and periosteum. contribute bone growth, remodeling and repair of bone. |
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Term
| What regulatory factors are secreted by osteoblasts? |
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Definition
| Macrophage-Stimulating factor (M-CSF), and Osteoclast differentiating factor (ODF). |
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Term
| What function does M-CSF do? |
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Definition
| permissive role for ODF/RANK complex which results in differentiation of Osteoclast precursor cells into full grown osteoclasts. |
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Term
| What factor regulates inhibits ODF from inducing differentiation and activation in osteoclasts? |
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Definition
| Osteoprotegerin (OPG), which competes with ODF to bind to RANK. As OPG binds to RANk, it creates and inactive complex. |
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Term
| What are factors that stimulate production of RANK and what are the ramifications of this? |
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Definition
| glucocorticoids, PTH, TNFa, IL's. Result in increased bone resorption |
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Term
| Factors that inhibit production of RANK |
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Definition
| estrogen. Result is that it stimulates bone formation. |
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Term
| Factors that stimulate OPG production |
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Definition
| Estrogen, leptin, mechanical stress. Result: blocks RANK and favors bone formation. |
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Term
| Factors that inhibit OPG production |
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Definition
| glucocorticoids, cyclosporin A.(an immunosuppressive agent) Resultant increased activity of RANK and bone resoprtion. |
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Term
| What are the 4 ways that blood is supplied to the bones? |
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Definition
| Nutrient Artery, Periosteal system, Metaphyseal system, Epiphyseal system |
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Term
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Definition
| supplies the inner cortex from within endosteal linings. high pressure system, divides after reaching the medullary cavity, sending arteriole branches in proximal & distal directions to join w/ metaphyseal arteries. |
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Term
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Definition
| forms extensive network of vesels covers entire length of bone shaft. Supplies outer cortex (1/3). very important in children for circumferential bone growth. |
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Term
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Definition
| Supplies the zone of provisional calcification in the physis. anastomoses w/ nutrient artery system. |
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Term
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Definition
| supplies layers of physis by diffusion. Arterial supply of the cortex is centrifugal and venous flow is centripetal. |
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Term
| T/F. Arterial suupply of the cortex is centrifugal (inside to out) while venous slow is centripetal (outside to in) |
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Definition
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Term
| Endochondral Ossification |
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Definition
| From a preformed cartilaginous structure. Longitudinal Growth, part of the diaphysis adjacent to the epiphyseal cartilage is the site of advancingn ossification. |
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Term
| Intramembranous Ossification |
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Definition
| De novo at specific sites in the skeleton. Diameter of bone growth (thickening the bone). direct transformation of fibrous matrix into osteoid. |
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Term
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Definition
| genetic defect of endochondral ossification: dwarfism. people with achondroplasia produce less cartilage, so limbs are shorter. |
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Term
| Key features of Genetic defect in Achondroplasia |
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Definition
| Fibroblast growth factor receptor 3 gene. point mutation: single nucelotide mutation. Mutation results in a sustained activation of FGFR3, that in turn inhibits the normal proliferation of cartilage at the growth plate. |
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Term
| Is achondroplasia inherited as an autosomal dominant or recessive trait? |
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Definition
| autosomal dominant for most variants. autosomal recessive for the rare lethal type II variants. |
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Term
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Definition
| genetic defects in encoding type I collagen: could be insufficient or poor quality of collagen |
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Term
| What kind of inheritance pattern is seen with osteogenesis imperfecta? |
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Definition
| autosomal dominant for most common variants |
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Term
| What are the phenotypes of osteogenesis imperfecta? |
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Definition
| brittle bone, bone deformity & fractures. |
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Term
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Definition
| consists of 2 proa1 chains and 1 proa2 chain. triple helical section with 338 tandem gly-X-Y. glycine smallest and substitution is disruptive. |
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Term
| Type I osteogenesis imperfecta |
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Definition
| diminished type I collagen production. brittle bone but no bony deformity. infrequent substitution of glycine. |
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Term
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Definition
| structural defects in type I collagen. substituion of glycine in the triple helix region. fracture. bony deformities. |
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Term
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Definition
| marble bone disease. stone-like and thickened appearance, autosomal or recessive trait. defect in ostoclasts which are unable to resorb collagen. bones thick and brittle. fractures common. |
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Term
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Definition
| bacterial infection of bones commonly by pyogenic cocci. usually originates in metaphysis. |
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Term
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Definition
| originates in metaphysis. PMN leukocytes to site of infection pus formation, enzymes lyse bone. formation of sequestra. iNVOLUCRUM AROUND ZONE OF INFLAMMATION TO PREVENT SPREAD OF INFECTION. Bone deformities predisposing to fractures. Common after bone surgery. |
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Term
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Definition
| absolute reduction of bone mass. most prevalent bone disease. |
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Term
| Multiple factors of osteoporosis |
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Definition
| hormonal changes: estrogen, PTH, corticosteroids; Early Menopause; Diet: Ca2+ and vitamin D; activity level; gentic predisposition; inital bone mass; kidney disease: 1,25 dihydroxy vitamin D. |
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Term
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Definition
| softening bones with inadequate mineralization of bone matrix due to abnormal vitamin D or phosphate metabolism. |
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Term
| What are some causes of Osteomalacia |
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Definition
| vitamin d deficiency, abnormal phosphates, growth retardation, bone deformities: bowlegs, serum Ca2+ and phosphate are low but PTH is high with Vit. D deficiency, phosphate is low but normal Ca 2+ and PTH levels with phosphate deficiency. |
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Term
| Vitamin D deficiency causes |
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Definition
| inadequate intake, inadequate sunlight exposure, abnormal GI malabsorption |
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Term
| Abnromal phosphate causes |
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Definition
| abnormal GI malabsorption. excess loss of phosphate in the presence of hyprparathyroidism. |
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Term
| What are the actions of Vitamin D? |
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Definition
| promotes action of PTH on resorption of Ca2+ and phosphate from bone. stimulates production of 1,25 D3 of kidney. role is not clear. |
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Term
| Paget's Disease definition |
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Definition
| osteitis deformans. characterized by irregular restructuring of bone that leads to thickening and deformities. |
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Term
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Definition
| Destructtive Phase: resorption; Mixed Phase: resorption counterbalanced by formation; Osteosclerotic phase: TBs thickened and CBs replaced by wide, sclerotic, dense bones. |
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Term
| Clinical Features of Paget's Disease |
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Definition
| Affected sites: cranium, long bones of LE, vertebrae; Osteosarcoma develops in some pt.s, mental deterioration, cardiovascular & pulmonary impairments. |
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Term
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Definition
| calcitonin and bisphosphate have been used to inhibit bone resorption and manage pain. |
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Term
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Definition
| injured tissues and platelets release vasoactive mediators, growth factors and other cytokines. influence cell migration, proliferation, differentiation and matrix synthesis. fibroblasts, mesenchymal cells & ostoprogenitor cells to the fracture site. |
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Term
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Definition
| 2 days-2 weeks. vasoactive substances cause neovascuularisation & local vasodilation. undifferentiated mesenchymal cells migrate to fracture site and have ability to form fibroblasts and chondroblasts which in turn form cartilage, bone or fibrous tissue. |
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Term
| What are the reparative phase callus? |
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Definition
| External callus: from fracture hematoma, ossifies by endochondral ossificatino to form woven bone; Internal callus: forms more slowly and occurs later; Periosteal Callus: forms directly from the inner periosteal cell layer. Ossifies by intramembranous osification to form woven bone. |
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Term
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Definition
| remodeling of woven bone is dependant on wolff's law. Cortical bone- remodelling occurs by invasion of osteoclast, which is followed by osteoblast. Cancellous bone- remodeling occurs on surface of trabeculae which causes trabeculae to become thicker. |
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Term
| Problems with severe injury |
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Definition
| post-traumatic arthritis, growth abnormalities, delayed union, malunion. |
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Term
| Factors influencing bone healing |
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Definition
| age, type of fracture, location of fracture, type of bone, blood supply, infection, functional activity, hormones, cortisone, TH, GH. |
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Term
| Cortisone effect on factors influencing bone healing |
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Definition
| decreases healing by decreasing callus production. |
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Term
| Thyroid Hormone effect on factors influencing bone healing |
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Definition
| increases healing by increasing bone remodeling |
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Term
| Growth Hormone effect on factors influencing bone healing |
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Definition
| increases healing by increasing callus production. |
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