shortly explain mechanism of pth hormone on bone kidney and intestine

Answer 1

The parathyroid hormone (PTH) is produced by the parathyroid glands and plays a crucial role in maintaining blood calcium levels.

1. Bone: PTH stimulates bone resorption, which is the breakdown of bone tissue. It does so by activating cells called osteoclasts, which release enzymes that break down the bone matrix. This process releases calcium into the bloodstream, increasing its levels.

2. Kidney: PTH acts on the kidneys to enhance calcium reabsorption. It decreases the excretion of calcium in urine, preventing its loss from the body. Additionally, PTH promotes the conversion of inactive vitamin D into its active form, calcitriol. Calcitriol increases calcium absorption from the intestines and enhances its reabsorption from kidneys.

3. Intestine: PTH indirectly affects the intestine by promoting the production of calcitriol, which increases calcium absorption from the intestines. Calcitriol stimulates the synthesis of proteins that transport calcium across the intestinal cells, allowing it to enter the bloodstream.

Overall, the mechanism of PTH hormone on bone, kidney, and intestine involves increasing calcium release from the bone, enhancing calcium reabsorption in the kidneys, and stimulating calcium absorption in the intestines. This coordinated action helps to maintain appropriate blood calcium levels for optimal body functions.