For example, they can break down our hydroxy appetite and they can release the calcium, the phosphate, back into the blood. So osteoclasts are the cells responsible for resorbing bone and that basically means they break down bone and they break down the extracellular matrix and release the minerals such as calcium and phosphate into the blood. Now, at times that can actually be helpful because let's say our muscle cells require calcium to contract. And if we need our calcium, this is how our bone basically releases the calcium so that the muscles can actually contract. And when we discuss the process of reforming and remodeling our bone, the osteoclast and the osteoblast basically play a crucial role in that process. So the bone is a living tissue, it's continually being reformed.