too much calcium; deposit into bones or excrete
with hypercalcemia, PTH and calcitonin
pth decreases, calcitonin increases
what happens to threshold and ap with hypercalcemia?
increases threshold making it harder for AP's
too little calcium; increase PTH (osteoclasts degrade bone)
stimulates osteoblasts to put Ca in bone
what secretes PTH?
how does pth increase blood calcium levels?
bone resorption, kidney resorption, vit D increases absorption
vitamin D activates
liver and kidney
sun on skin makes which vit D?
decreased Ca-->PTH makes what form of vitamin D in the kidneys?
2 direct targets of pth?
kidney and bone
hypothal (ghrh), ant pit (gh), liver (igf)
inhibits ghrh, stim ghih; inhibits gh
decrease bone formation, increase breakdown
decreases apoptosis, decreases osteoclast
increases bone formation, inhibits resorption
decrease plasma Ca/promote bone deposition
calcitonin, gh, igf, sex hormones
increases plasma Ca/promote resorption
PTH, vitamin D (dihydroxy), cortisol