osteoporosis Flashcards
cortical bone more compacted and trabecular more spongy
trabecular function
where can we find this type of bone too
spaces fro red marrow storage and strength and lightness - honey Combe
found mainly at end of long bones, inner parts of short flat and irregular bones and orientated along lines of stress
cortical bone has a major role in support and fusion composed of Haversian systems containing blood vessels, lymphatic vessels and nerves
found where
shaft of long bones, thick walls in diaphysis, thinner walls towards metaphysics, surrounds the medullary cavity and bone marrow, surrounds the trabecular bone at ends of long bones, surrounds trabecular bone of vertebral bodies and other irregular bones
osteogenic cells
unspecialised stem cell derived from mesenchyme only bone cell to divide daughter cells are osteoblasts found along inner portion of periosteum endosperm canals within bone contain blood vessels
posteobalsts are bone forming cells
bone marrow derived pluripotent stroll cells
synthesis and secrete most of proteins of bone matrix
high levels of alkaline phosphatase - mineralization
osteoclasts
develop from riculating monocytes mutlinucelated cells carry out bone resorption specialised area of cell membrane - ruffled border acidic ph soubises mineral proteolytic enzymes digest matrix
oesteocytes
mature bone cells
formed from osteoblasts when isolated in structure they produce
cellular structure changes
maintain cellular activité son bone
participate in regulation of bone turnover
who is affected by osteoporosis
women - after menopause when sex levels decrease
men - low bone strength
younger - usually underlying condition or reason is identified
duel energy Xray absorptiometry DEXA used to diagnose it
osteoporosis is defined as a BMD T soft of what
-2.5 or less at either the lumbar spine or the femoral neck
BMD - is amount of bone mass
what is a Z score
nroamlsies a patents BMD by assessing the amount of bone loss compared to the expected bone loos for age matched peers
what is a T score
quantifies difference between patients BMD and peak bone mass for young normal
normal is higher than -1
-1 to -2.5 is osteopenia
and above that osteoporosis
treatment for osteoporosis
bisphosphonates - inhibitors of bone resorption decreasing osteoclastic activity - alendronate - oral or zoledronic acid - IV
raloxifine - post menopausal osteoporosis - SERM and HRT increase osteoblasts
Denosumab - monoclonal antibody inhibits osterolcast formation and decrease bone resorption
parathyroid horse increase bone formation and increase activity of OB
also supplements fro
calcium - 700mg
vit D - 10mg
sunlight - activate via d
exercise good reduced risk of fractures
benefits outweigh risks
adapt movements
osteoblasts activate monocytes with what
M-CSF
OB detect stress fractures which make
RANK-L
monocytes have receptors for this so fuse together osteoclasts to make collagenase and HCL
then RNKL neutralised buy osteoprotegerin
in osteoporosis bone is reabsorbed by osteoclasts quicker than it is rebuilt by OB , decreased bone density but normal bone , peak bone mass reaches in 20s then steadily decline sin menopause
RF
decreased amount of normally mineralised bone
decreased exposure to oestrogen - post menopausal late menses , early menopause white people hypoclacaima smoking steroids which inactive vit d not enough weight bearing exercise
types of OP
post menopausal reduced oestrogen increased bone resorption - over 50s
senile - OB can build but continue to activate OC - over 80s
