Question

Briefly describe the role of calcium in the bone homeostasis and in skeletal muscle regulation. (think of the role of hormones and events during muscle contraction

Answer 1

Calcium is an important mineral stored in the bones. It, alongwith phosphorus , gives the strength to the skeletal framework. The calcium is laid down by osteoblasts under the influence of calcitonin and vitamin D while osteoclasts cause resorption of bone and remodelling (under the influence of parathyroid hormone) which is required to manage the concentration of calcium ion in blood.

Calcium plays a crucial role in skeletal muscle contraction as well. Once an action potential arrives at a neuromuscular junction, influx of calcium takes place in the muscle cells which causes further release of calcium from the sarcoplasmic reticulum. This released calcium binds to a protein on the myosin binding site on actin , to free it for binding with myosin and contraction to occur.