Confocal micrograph of osteoblast cells labeled with Alexafluor 488 that stains alpha tubulin (green) and phalloidin marking the actin (purple) and DAPI highlighting the nucleus (yellow). Osteoblasts originate in bone marrow and contribute to the production of new bone. These cells build up the matrix of bone structure and as bone is continually being reabsorbed and regenerated these are very crucial cells. Osteoblasts make up bone and osteoclasts break it down.