The 'Hormone Parathyroid Hormone' (PTH) is secreted by the parathyroid glands. Its primary effect on blood calcium levels is to: MCQ with Answer and Explanation

Parathyroid Hormone (PTH) is a peptide hormone secreted by the chief cells of the four parathyroid glands in response to low blood calcium levels (hypocalcemia). Its primary function is to increase blood calcium levels (hypercalcemic effect). It achieves this by: 1) Stimulating osteoclasts to break down bone, releasing calcium. 2) Increasing calcium reabsorption and stimulating the activation of Vitamin D in the kidneys. 3) Indirectly increasing calcium absorption in the gut via active Vitamin D. It has the opposite effect of calcitonin.