Parathyroid Glands
The parathyroid glands are actually four (some people may have more) small, bean-shaped structures that are each surrounded by connective tissue and embedded with the lateral lobes of the thyroid (Timby & Smith, 2013, p. 750). These glands secrete parathyroid hormone (PTH) which is an antagonist to calcitonin from the thyroid. PTH stimulates the breakdown of bone which then causes the release of calcium in the blood. Phosphorus is also released from the bones at this time, so the parathyroid gland also regulates the amount of phosphorus in the blood. This may occur when there is a low calcium level in the serum due to poor calcium intake, kidney failure, result of medications, etc. In addition to releasing calcium from the bones, PTH promotes conservation of calcium by the kidneys by interfering with the urinary excretion of calcium, however still promotes urinary excretion of phosphorus. PTH also activates Vitamin D, which then allows intestines to absorb calcium (Timby & Smith, 2013).
The parathyroid glands are actually four (some people may have more) small, bean-shaped structures that are each surrounded by connective tissue and embedded with the lateral lobes of the thyroid (Timby & Smith, 2013, p. 750). These glands secrete parathyroid hormone (PTH) which is an antagonist to calcitonin from the thyroid. PTH stimulates the breakdown of bone which then causes the release of calcium in the blood. Phosphorus is also released from the bones at this time, so the parathyroid gland also regulates the amount of phosphorus in the blood. This may occur when there is a low calcium level in the serum due to poor calcium intake, kidney failure, result of medications, etc. In addition to releasing calcium from the bones, PTH promotes conservation of calcium by the kidneys by interfering with the urinary excretion of calcium, however still promotes urinary excretion of phosphorus. PTH also activates Vitamin D, which then allows intestines to absorb calcium (Timby & Smith, 2013).