Recruitment of Osteoclasts from Hemapoetic Precrusors in the Blood Is

Question

Recruitment of osteoclasts from hemapoetic precrusors in the blood is stimulated by
A) PTH and calcitonin
B) PTH alone
C) Calcitonin alone
D) PTH and 1,25 dihydroxycholecalciferol
E) CT and 1,25 dihydroxycholecalciferol

Accepted Answer

PTH (Parathyroid Hormone) and 1,25-dihydroxycholecalciferol (the active form of Vitamin D) stimulate the recruitment of osteoclasts from hematopoietic precursors in the blood. PTH increases blood calcium levels by promoting bone resorption, while 1,25-dihydroxycholecalciferol enhances calcium absorption in the gut and promotes the action of PTH. Calcitonin, on the other hand, works to lower blood calcium levels by inhibiting osteoclast activity.