bones Flashcards
which site is preferred for bone marrow transplantation
iliac cret
where does red bone marrow persist into adulthood
spongy bones of vertebrae, ribs, sternum, cranium and epiphyses of long bones
what is the role of sclerostin
inhibits bone growth
which mab for osteoporosis? what does it do
romosozumab - inhibits sclerostin
osteoclasts dissolve hydroxyapatite by pumping acid onto it. how do they maintain their own intracellular pH
also peeing out HCO3- from the “back side”
what enzymes complete the hydrolysis of matrix proteins during bone resorption
Cathepsin K and collagenases
osteoblasts secrete… what is it
osteoid - unmineralised bone cement
what do osteoblasts become and where do they live
osteocytes, in lacunae
A - osteoblast
B - osteocyte
C - unmineralised osteoid
D - cement line
E - mineralized bone
what regulates elimination of phosphate via the kidneys, which directly impacts on the calcium balance
FGF23
what lowers plasma Ca levels by directly inhibiting oscteoclast activity
calcitonin
what sort of parathyroidism do you get with renal failure
secondary hyperparathyroidism
drug used in treating secondary hyperparathyroidism in patients with chronic renal failure on dialysis. moa
cinacalcet
allosterically sensitises CaSR receptor, leading to less parathyroid secretion
2 brand names for cinacalcet
sensipar
mimpara
where does the last hydroxylation of vit D take place
PCT
what stimulates the last hydroxylation of vit D
PTH
what inhibits the last hydroxylation of vit D
calcitriol, FGF23 and/or phosphate
how does vit D induce the precipitation of Ca and phosphate in osteoid
raising the concentrations in plasma above the solubility maximum
how does calcitriol help stop fractures
increases formation of collagen 1 by osteoblasts
where is the central target organ of calcitriol. why
duodenum, increase absorption of Ca
what is the overriding effect of FGF23
reduces serum phosphate levels
what happens in gain of function FGF23 mutation in a baby
hypophosphataemic ricketts
what happens if you get paraneoplastic FGF23 GOF mutation
tumour-induced osteomalacia
what happens if FGF23 doesn’t work
hyperphosphatemic familial tumoral calcinosis. extra calcium deposits everywhere. very bad
which X-linked gene can cause hypophostphataemia
PHEX
which enzyme does the final hydroxylation of vit D
1-alpha-hydroxylase
lack of thyroid hormone in children causes
dwarfism
hyperthyroidism effect on bones
osteoporosis
FSH stimulates which bone cell activity
osteoclast
