PTH vs. calcitonin in calcium balance
Low blood calcium triggers release of which hormone, with which effect?
Answer C: explanation for every choice
A
Calcitonin is released when calcium is high and decreases bone resorption.
B
PTH increases calcitriol production by stimulating 1α-hydroxylase in the kidney.
C
Correct. PTH raises calcium by increasing bone resorption, kidney reabsorption of calcium, and activation of vitamin D.
D
Calcitonin lowers blood calcium. It is released when calcium is high.
TakeawayPTH raises calcium. Calcitonin lowers it.
Next question →
Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb92.