MICROANATOMY

Detailed explanation-1: -In the kidneys, the parathyroid hormone has 3 functions in increasing serum calcium levels. Most of the physiologic calcium reabsorption in the nephron takes place in the proximal convoluted tubule and additionally at the ascending loop of Henle.

Detailed explanation-2: -The parathyroid glands release parathyroid hormone (PTH) in response to a decrease in serum calcium. PTH acts on the kidneys to increase calcium reabsorption in the ascending loop of Henle, the distal convoluted tubule, and the collecting duct.

Detailed explanation-3: -When the calcium level is high in the bloodstream, the thyroid gland releases calcitonin. Calcitonin slows down the activity of the osteoclasts found in bone. This decreases blood calcium levels. When calcium levels decrease, this stimulates the parathyroid gland to release parathyroid hormone.

Detailed explanation-4: -The parathyroid hormone produced by the thyroid glands helps maintain the right balance of calcium in the bloodstream and in tissues that depend on calcium for proper functioning. This is especially important for nerve and muscle function, as well as bone health.

Detailed explanation-5: -The parathyroid glands’ function is to maintain serum calcium homeostasis through synthesis and release of PTH. At the bone, PTH inhibits osteoblast activity and stimulates osteoclast activity leading to bone breakdown and calcium release.