The parathyroid glands are small, round structures that are located on the surface of the thyroid gland in the neck region. They produce a hormone called parathyroid hormone (PTH), which is responsible for regulating the body’s calcium levels. When calcium levels drop too low, PTH signals the body to release stored calcium from bone tissue and increase its absorption in the intestines. Additionally, PTH helps regulate phosphorus levels in the bloodstream and stimulates bone turnover to maintain calcium homeostasis. The parathyroid glands also play an important role in helping to regulate blood pressure by modulating sodium and potassium concentrations. Furthermore, they help to regulate nerve transmission by controlling calcium concentration within nerve cells, as well as influencing neurotransmitter release. Abnormal functioning of these glands can lead to several conditions such as hypoparathyroidism or hyperparathyroidism, leading to serious medical problems such as weakened bones or kidney stones. As such, it is important for people with these conditions to have their parathyroid glands checked regularly for proper functioning.