What role does parathyroid hormone play in bone health?

Parathyroid hormone (PTH) plays a crucial role in maintaining calcium homeostasis in the body, particularly in relation to bone health. When calcium levels in the blood drop, parathyroid hormone is secreted by the parathyroid glands. This hormone works to increase blood calcium levels through several mechanisms.

Firstly, PTH stimulates osteoclasts, which are cells responsible for bone resorption. By increasing the activity of osteoclasts, PTH promotes the breakdown of bone tissue, which releases stored calcium into the bloodstream. Additionally, PTH enhances the reabsorption of calcium in the kidneys, reducing calcium loss in urine. It also promotes the activation of vitamin D, which increases intestinal absorption of calcium.

Thus, parathyroid hormone's primary function is to elevate calcium levels in the blood, making this option the most accurate representation of its role in bone health. The other options do not reflect the multifaceted actions of PTH in relation to bone and calcium metabolism.