How does the body compensate for high blood calcium levels?

The body compensates for high blood calcium levels through the secretion of calcitonin. When calcium levels in the blood rise above normal, the thyroid gland releases calcitonin, a hormone that helps lower blood calcium levels. Calcitonin acts primarily by inhibiting the activity of osteoclasts, which are the cells responsible for breaking down bone and releasing calcium into the bloodstream. Additionally, calcitonin can enhance the excretion of calcium through the kidneys and decrease intestinal absorption of calcium.

This mechanism is essential for maintaining calcium homeostasis in the body. By counteracting the effects of parathyroid hormone (PTH), which increases blood calcium levels by promoting bone resorption, enhancing intestinal absorption, and reducing renal excretion of calcium, calcitonin plays a critical role in restoring balance when blood calcium levels are elevated.