How does hyperparathyroidism affect the body's calcium levels?

Hyperparathyroidism is characterized by an overproduction of parathyroid hormone (PTH) by the parathyroid glands. PTH plays a critical role in regulating calcium levels in the body. When PTH is secreted in excess, it leads to increased bone resorption, meaning that calcium is released from the bones into the bloodstream. This process raises the overall calcium levels in the blood.

Additionally, hyperparathyroidism can cause increased absorption of calcium from the intestines and decreased renal excretion of calcium, further contributing to elevated calcium levels. Over time, the sustained elevation of calcium in the blood can lead to a condition known as hypercalcemia, which can have various clinical implications, including kidney stones and cardiovascular issues.

Thus, the correct response highlights that hyperparathyroidism leads to an increase in calcium levels in the body due to the mechanisms the hormone initiates concerning bone metabolism, intestinal absorption, and renal function.