Final answer:
Hyperparathyroidism is a disorder characterized by excessive calcium reabsorption from bone, resulting in decreased bone density and other complications. It is caused by an overproduction of parathyroid hormone and can lead to high serum calcium levels and kidney stones.
Step-by-step explanation:
Hyperparathyroidism is a disorder caused by an overproduction of PTH, resulting in excessive calcium reabsorption from bone. This can lead to decreased bone density, fractures, and deformities. As blood calcium levels rise, the responsiveness of the nervous system is reduced and calcium deposits may collect in tissues and organs. Abnormally high activity of the parathyroid gland can cause hyperparathyroidism, which is characterized by high serum calcium, low serum phosphate, bone destruction, and kidney stones.