As plasma levels of calcium decrease
A)insulin is secreted.
B)the parathyroid glands secrete an osteoclastic hormone.
C)the kidneys excrete calcium and phosphorus.
D)calcitonin is secreted.

Question

Quizplus · Accepted Answer

When plasma levels of calcium decrease, the parathyroid glands secrete parathyroid hormone (PTH), which stimulates bone resorption by osteoclasts, releasing calcium into the bloodstream.

Answer D and A are incorrect because when plasma levels of calcium decrease, calcitonin is not secreted, and insulin secretion is not affected. Option C is also incorrect because, in response to low calcium levels, the kidneys conserve calcium and excrete phosphorus.

As Plasma Levels of Calcium Decrease