An osteoclast (from the Greek words for "bone" and "broken")'s a type of bone cell that removes bone tissue by removing its mineralized matrix and breaking up the organic bone (organic dry weight's 90% collagen). This process's known as bone resorption. Osteoclasts and osteoblasts are instrumental in controlling the amount of bone tissue: osteoblasts form bone, osteoclasts resorb bone. Osteoclasts are formed by the fusion of cells of the monocyte-macrophage cell line. Osteoclasts are characteri… (More on Osteoclast)