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47 Cards in this Set
- Front
- Back
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osteoporosis is defined as a bone mineral density less than ... standard deviations below the young normal mean?
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2.5
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in osteoporosis, what effect is there on mineralisation of bone?
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mineralisation is generally normal
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what type of bone is more affected by the imbalance in bone remodelling in osteoporosis?
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trabecular
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what gives bone its compressive strength?
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bone mineral - hydroxyapatite
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what is the result of insufficient calcium and phosphate to mineralise newly formed osteoid?
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osteomalacia
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what is the most serious fracture in older people?
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hip fracture
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t/f... high body weight is a risk factor for hip fracture
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false, this is true for low body weight
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what is the recommended dietary intake of calcium for the elderly?
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800 to 1200 mg per day
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what is the most important factor in determining peak bone mass
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genetics
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t/f... smoking is a risk factor for osteoporosis
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true
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what is the frequency of falls in those aged >65?
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1 in 3 have at least 1 fall a year
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what is the most common fracture in older women?
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hip
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what is the most common fracture in younger women?
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colles
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the use of which single drug has the highest association with falls?
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psychoactive medication
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how much calcium is in the blood?
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2.3-2.5 mmol/L
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what is the long term effect of raised extracellular calcium?
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kidney calcification and stones
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what is the long term effect of high PO4?
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soft tissue mineral deposition
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what is the long term effect of low phosphate?
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inadequate bone mineralisation
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what increases the release of parathyroid hormone?
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low calcium
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what two factors decrease the release of parathyroid hormone?
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calcitriol and high calcium
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what is the main source of vitamin D?
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sun exposure
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where is vitamin d transformed into 25-OH-vitamin d?
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liver
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what is the conversion of 25 (OH)vitamin D to calcitriol increased by?
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PTH (low calcium), low phosphate, growth, pregnancy
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what is the main function of calcitriol?
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to acquire calcium and phosphate from food for bone mineral
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what is the release of calcium and phosphate from bone increased by?
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PTH, calcitriol
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what inhibits the release of calcium and phosphate from bone?
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calcitonin
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what are the effects of low blood calcium?
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increased PTH release, increased calcitriol in kidney (conservation of calcium, dumping of phosphate), increased absoption of calcium and phosphate in gut, increased resorption of bone,
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what is the major effect of low blood phosphate?
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increased calcium and phosphate absorption in gut
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what are the determinants of bone mass?
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genetics, age, mechanical loading, mineral balance, vitamin D, parathyroid hormone, sex steroids
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at what age is bone mass at its peak?
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20-30 years
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what are the determinants of peak bone density?
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genetic, exercise, calcium intake, adequate vitamin D, normal sex steroids
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what is the recommended daily calcium intake?
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800-1200 mg/day
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what is the source of vit D3?
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animal sources
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what is the source of vit D2?
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plant sources
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what is the target level of vitamin D?
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50-80nmol/L 25(OH)D
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what is the result of severe vit D deficiency?
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osteomalacia
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t/f... intermittent PTH stimulates bone formation
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true
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which layer of the skin is of ectodermal origin?
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epidermis
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which layer of the skin is of mesodermal origin?
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dermis
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which regions of the body have very thick layers of epidermis?
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palms of hands and soles of feet
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what are the cells of the epidermis?
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keratinocytes
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where in the epidermis are the youngest keratinocytes?
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basal layer
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how is the basal layer of the epidermis attached to the dermis?
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by hemidesmosomes and pedicles
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how are cells in the stratum spinosum attached to each other?
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by desmosomes
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what is the function of the stratum corneum?
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protection against abrasion
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what are the two layers of the dermis of thick skin?
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papillary layer and reticular layer
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what is the main cell type in the dermis?
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fibroblast
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