PSL201Y1 Chapter Notes - Chapter 19,21,6: Osteomalacia, Calcitriol, Parathyroid Gland
Document Summary
The thyroid glands secretes 3 hormones; t3, t4 and calcitonin. T3 and t4 regulate the body"s metabolic rate while calcitonin decreases blood calcium levels in the body. The parathyroid, located on the posterior surface of the thyroid gland secretes the parathyroid hormone (pth) which is an important regulator of calcium levels in the blood. Pth acts on the bones, kidneys and intestines to increase blood calcium levels. It functions in exocytosis, muscle contraction, increases contractility of the heart and blood vessels, formation of bones and teeth and in blood clotting. 99 percent of the calcium found in the body is in the bones. Calcium can be added to the plasma from bone and absorbed via the gastrointestinal tract. It can also be removed from the plasma by bone and the kidneys. The bone provides a reservoir for calcium when calcium levels are low. In the process of resorption, the bone is broke down to liberate calcium ions.
