If Blood Calcium Levels Drop Below 8

Question

If blood calcium levels drop below 8.5 mg/dL which hormone is likely to be activated?
A) parathyroid hormone
B) estrogen
C) calcitonin
D) calcitriol
E) both calcitriol and parathyroid hormone

Accepted Answer

When blood calcium levels drop below normal, the body responds by activating parathyroid hormone (PTH) and calcitriol. PTH increases calcium levels by stimulating the release of calcium from bones, increasing calcium reabsorption in the kidneys, and promoting the activation of vitamin D to calcitriol, which helps increase calcium absorption from the gut.