The hormone that is produced in response to falling blood calcium levels and that stimulates the activation of vitamin D is
A) insulin.
B) cortisol.
C) parathyroid hormone (PTH).
D) calcitonin.

Question

Quizplus · Accepted Answer

Parathyroid hormone (PTH) is produced by the parathyroid glands in response to falling blood calcium levels. PTH stimulates the release of calcium from bones, increases reabsorption of calcium by the kidneys, and promotes the activation of vitamin D, which helps increase absorption of calcium from the intestines. Insulin and cortisol do not play a role in calcium regulation, and calcitonin actually works to lower blood calcium levels rather than increase them.

The Hormone That Is Produced in Response to Falling Blood