Question

2. Describe the role of hormones in calcium regulation and how bone, kidney, and the intestines are involved. Describe how this influences bone deposition and resorption.

Answer 1

2. Parathyroid Hormone (PTH) produced by parathyroid gland and Calcitonin, hormone produced by thyroid glands, regulates the calcium levels in blood. PTH is released when calcium levels are low while Calcitonin is released when the calcium levels are high in blood.This regulation is done through 3 modes or mechanisms that is through bones, kidneys and intestine. PTH stimulates or triggers Osteoclasts to break down bones and thus to release calcium from the broke down bone into the bloodstream. Calcitonin, on the other hand inhibits osteoclasts, thus reducing the levels of calcium in blood. PTH increases the resorption of the calcium in the kidney thus inhibiting the loss of calcium through urine and inturn increasing the calcium levels. Calcitonin reduces the resorption of calcium in kidneys. PTH stimulate the production of Calcitriol, which increases the absorption of calcium from the food in the intestine which increases the blood calcium levels . The release of PTH or low levels of calcium in blood will increase the bone resorption whereas release of calcitonin increases bone deposition.