Term
| connective tissue covering of bone |
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Definition
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Term
| dense outer layer of bone |
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Definition
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Term
| inner netowrk of thin trabeculae which lies within the marrow cavity |
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Definition
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Term
| mononuclear cells, synthesize collagen and ground substance |
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Definition
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Term
| osteoblasts that become embedded and incorporated in bone matrix |
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Definition
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Term
| multinucleated cells found along cortical endosteal surface, and trabeculae in scalloped bays called howships lacunae. involved in bone resoprtion in presence of PTH |
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Definition
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Term
| basic unit of compact bone |
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Definition
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Term
| basic unit of cancellous bone |
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Definition
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Term
| mineralized, mature osteoid tissue; collagen fibers laid down in parallel array |
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Definition
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Term
| mineralizd osteoid tissue; collagen fibers arranged haphazardly; found in bone regernation and tumors. may be replaced by lamelar bone |
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Definition
| woven bone (non-lamellar) |
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Term
| develop by endochondral ossification (replacement of cartilaginous surface by eone) |
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Definition
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Term
| develop by intramembranous ossification - mesenchymal cells idfferentiate directly into bone |
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Definition
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Term
| formation of bone depends on |
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Definition
| deposition of calcium and phosphate |
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Term
| calcium and phosphate metabolism is controlled by |
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Definition
| PTH, calcitonin and vitamin D metabolites |
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Term
| a disease characterized by increased porosity of the skeleton resulting from reduced bone mass |
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Definition
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Term
| predisposes the bone to fracture |
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Definition
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Term
| generalized osteoporosis may be |
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Definition
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Term
| peak bone mass is achieved |
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Definition
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Term
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Definition
| hereditary factors, physical activity, muscle strength, diet, hormonal state |
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Term
| maximal skeletal mass is attained |
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Definition
| after the third or fourth decade |
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Term
| occurs with every resorption and formation cycle |
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Definition
| a small deficit in bone formation (may average 0.7%/year |
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Term
| hormone dependent acceleration of bone loss |
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Definition
| postmenopausal osteoporosis |
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Term
| plays the major role in postmenopausal osteoporosis |
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Definition
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Term
| protective against bone loss |
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Definition
| estrogen replacement at menopause |
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Term
| decreased estrogen levels result in |
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Definition
| increased secretion of IL1, IL6 and TNF by blood monocytes and bone marrow cells |
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Term
| cytokine stimulators of osteoclast recruitment and activity |
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Definition
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Term
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Definition
reduced osteoblast potential
growth factors lose potency
result in a skeleton populated by bone forming cells that have a diminished capacity to make bone |
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Term
| postmenopausal and senile osteoporosis |
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Definition
| entire skeleton is affected |
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Term
| affects the cancellous compartment of vertebral bodies |
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Definition
| postmenopausal osteoporosis |
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Term
| trabeculae are thinned and lose their interconnections, leading to professive microfractures and eventual vertebral collapse |
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Definition
| postmenopausal osteoporosis |
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Term
| loss of bone is most rapid from trabecular bone |
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Definition
| postmenopausal osteoporosis |
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Term
| vertebrae - prominent trabecular component |
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Definition
| postmenopausal osteoporosis |
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Term
| decreased osteoblast response - reduced replication, reduced biosynthetic potential |
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Definition
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Term
| osteoporotic cortex is thinned by subperiosteal and endosteal resorption |
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Definition
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Term
| widened haversian systems |
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Definition
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Term
| multilevel fractures can cause |
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Definition
| significant height loss and deformities, lumbar lordosis and kyphoscoliosis |
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Term
| osteoporosis ______ be reliably detected in plain radiographs until ____ % of the bone mass is lost |
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Definition
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Term
| measurement of blood calcium, phosphorus, and alkaline phosphatase is |
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Definition
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Term
| best procedures that accurately estimate the amount of bone loss are |
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Definition
| specialized radiographi imaging techniques such as duel energy absorptiometry and quantitative computed toography which measure bone density |
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Term
| prevention and treatment of senile and postmenopausal osteoporosis |
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Definition
| exercise, appropriate calcium and vitamin D intake, pharmacologic agents, including estrogen replacing agents; bisphosphonates and recombinant PTH |
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Term
| Major function of vitamin D |
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Definition
| maintenance of normal plasma levels of calcium and phosphorous |
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Term
| maintains the correct concentration of ionized calcium in the ECF required for neural excitation and relaxation of muscle |
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Definition
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Term
| required for absorption of calcium from the small intestine |
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Definition
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Term
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Definition
endogenous synthesis in the skin(d3) by UV light
dietary sources - deep sea fish, plants, grains (d2) |
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Term
| can cause vitamin D deficiency |
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Definition
dietary deprivation, fat malabsorption, prolonged lack of exposure to sunlight
chronic renal failure - unable to convert vitamin D to active metabolites |
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Term
| cause rickets in children |
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Definition
| Vitamin D deficiency or phosphate depletion |
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Term
| cause osteomalacia (soft bones) in adults |
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Definition
| vitamin d deficiency or phosphate depletion |
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Term
| disorder in children in which deranged bone growth produces distincitve skeletal deformities |
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Definition
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Term
| in osteomalacia the bone that forms during remodeling is |
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Definition
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Term
| basic abnormality in rickets and osteomalacia |
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Definition
defective mineralization of osteoid
increased unmineralized matrix
wide osteoid seams and a decrease in calcified bone |
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Term
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Definition
pain
bone deformities including rachitic rosary (swollen costochondral junctions of ribs)
outward curvature of sternum (pigeon chest)
shortened and deformed limbs with severe bowing of arms and legs
frequent fractures
xray findings include thickened irregular lobulated epiphyseal plate |
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Term
| osteomalacia clinical signs |
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Definition
osteopenic xray pattern
compession fractures and decrease in bone thickness
in dietary vitamin d deficiency serum levels of calcium and phosphorous are low
low serum calcium levels stimulate PT glands and the development of secondary hyperparathyroidism |
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Term
| results from autnomous hyperplasia or a tumor, usually an adenoma, of the parathyroid gland |
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Definition
| primary hyperparathyroidism |
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Term
caused by prolonged states of hypocalcemia resulting in compensatory hypersecretion of PTH.
incresaed PTY levels are detected by receptors on osteoblasts, which then release molecules tha tstimulate osteoclast activity |
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Definition
| hyperparathyroidism affectssecondary hyperparathyroidism |
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Term
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Definition
| anatomic changes of severe hyperparathyroidism |
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Term
| more severe form of hyperparathyroidism |
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Definition
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Term
| in cancellous bone osteoclasts create the appearance of railroad tracks known as |
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Definition
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Term
| hyperPTH radiographic findings |
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Definition
| osteopenia (decreased bone density) |
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Term
| in hyperPTH what cells increase activity |
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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
| microfractures and secondary hemorrhages |
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Term
| sequestered multinucleated macrophages and an in growth of reparative fibrous tissue at microfracture sites create a mass f reactive tissue known as |
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Definition
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Term
| vascularity, hemorrhage, and hemosiderin deposition cause the color in |
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Definition
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Term
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Definition
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Term
| hallmark of severe hyperparathyroidism |
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Definition
increased bone cell
peritrabecular fibrosis
cystic brown tumors |
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Term
| _____ describes collectively all of the skeletal changes of chronic renal disease |
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Definition
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Term
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Definition
1. increased osteoclastic bone resorption mimicking osteitis fibrosa cystica
2. delayed matrix mineralization (osteomalacia)
3. osteosclerosis
4 growth retardation
5. osteoporosis assumed greater clinical importance |
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Term
| chronic renal failure results in |
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Definition
| phosphate retention and hyperphosphatemia |
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Term
| hyperphosphatemia induces |
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Definition
| secondary hyperparathyroidism because phosphate regulates PTH secretion |
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Term
| _____ develops as levels of vitamin D fall inrenal osteodystrophy because of decreased conversion from vitamin d metabolite |
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Definition
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Term
| _____ converts 25-(OH)D3 to the active metabolite 1,25-(OH)D3 |
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Definition
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Term
| _______ is inhibited by high levels of phosphorus, therefore intestinal absorption of calcium is reduced |
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Definition
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Term
| _____ suppresses PTH gene expression and secretion |
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Definition
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Term
| PTH secretion _____ at all levels of serum calcium in renal failure |
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Definition
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Term
| compromised renal function causes |
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Definition
| decreased degradation and excretion of PTH |
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Term
| secondary hyperparathyroidism produces |
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Definition
| increased osteoclast activity |
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Term
| stimulates bone resorption and the release of calcium hydroxyapatite from the matrix |
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Definition
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Term
| factors important in the genesis of osteodystrophy |
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Definition
iron accumulation in bone and aluminum deposition at the site of mineralization
(Al from dialysis solutions, interferes with calcium hydroxyapatite deposition, toxic to bone and can cause dialysis encephalopathy and microcytic anemia) |
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Term
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Definition
| B2-microglobulin which is increased in the serum of patients |
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