Answer & Explanation:
The parathyroid glands are located in the neck and are responsible for producing the hormone called parathyroid hormone (PTH). PTH plays a crucial role in maintaining the balance of calcium and phosphorus in the blood. It does this by regulating the activity of cells in the bones and kidneys, which control calcium and phosphorus levels.
When the calcium levels in the blood are too low, the parathyroid glands secrete PTH, which stimulates the release of calcium from bones and increases the reabsorption of calcium by the kidneys. PTH also decreases the reabsorption of phosphorus by the kidneys, which helps to maintain a proper balance between calcium and phosphorus.
On the other hand, when the calcium levels in the blood are too high, the parathyroid glands decrease PTH secretion, which reduces the release of calcium from bones and decreases the reabsorption of calcium by the kidneys. This helps to prevent the calcium levels in the blood from getting too high.