Schricker study guide Flashcards
mineral component of bone
hydroxyapetite
primary protein component of bone
collagen
remodeling cycle and serum calcium levels
increase in serum calcium bone synthesis occurs which increases bone mass, this result sin decrease in serum calcium, resulting in bone resportpion and decrease in bone mass, etc, etc
where else is calcium found
teeth
how is calcium distributed in serum
50% ionized calcium
40% proteinbound to albumin
10% bound to citrate/phosphate
protein bound calcium is biologically inactive/active
inactive
ionized calcium is inactive/active
active
cells involved in bone remodleing cycle
mesenchymal, osteoblasts, hematopoeitic stem cells, osteoclasts
what factors regulate bone remodeling cycle
serum calcium (inhibits resporption) hormones, cytokines
major consequences of increased PTH
resportion of bone which decreases bone mass
what regulates pth production
stimulated by low plasma calcium levels
increased vitamin d increases
serum calcium levels, gut adsorption of calcium, and bone adsorption
what regulates vitamin d production
1-alpha hydroxylase in kidney
tumors produce what protein
Parathyroid hormone related protein which has a seuqnce homology with PTH and icnreases production of growth factos
osteomalcia
defects in HA formation due to vitament D deficiency (causes rickets, cured by cod liver oil)
osteoporosis
loss of mineral density with age, increase risk of fracture, rates of bone syntehsis and resporption change (treatments with estrogen, biphosphonates, calcitonin)
pagets disease
excessive breakdown of bone followed by disorganized repair of bone, problems with osteoblasts/osteoclasts
rankL binds to
RANK on osteoclasts
when RANKL binds to RANK, it triggers
osteoclasts to resorb bone
OPG inhibits RANKL from binding to
RANK
estrogen activates
OPG
PTH indirectly stimualates
osteoclasts
hypercalcemia is low/high calcium in blood
high
hypercalcemia is caused by
high PTH levels
hypocalcemia is low/high calcium in blood
low
hypocalcemia is caused by
low PTH levels
