Question

PTH causes the blood levels of calcium to ________ and calcitonin causes it to ________ a. increase, increase b. increase, decrease c. decrease, increase d. decrease, decrease

Short answer

b. increase, decrease

Step-by-step solution

Understanding the Roles of PTH and Calcitonin

PTH (parathyroid hormone) is a hormone released by the parathyroid glands which is located in the neck. Its primary purpose is to regulate blood calcium levels, which is essential for proper functioning of muscles, nerves, and other vital body functions. PTH acts to raise blood calcium levels when the levels are low. Calcitonin, on the other hand, is a hormone released by the thyroid gland, which is also located in the neck. Like PTH, calcitonin also plays a role in regulating blood calcium levels. However, its primary purpose is to lower blood calcium levels when the levels are too high.

Comparing PTH and Calcitonin Effects

Based on the roles of PTH and calcitonin defined in Step 1: - PTH causes blood calcium levels to increase (when they are low). - Calcitonin causes blood calcium levels to decrease (when they are too high).

Selecting the Correct Option

Comparing our findings from Step 2 with the choices given, we can see that the correct answer is: b. PTH causes the blood levels of calcium to increase, and calcitonin causes it to decrease.