Osteoclast. Coloured transmission electron micrograph (TEM) of an osteoclast (orange). Osteoclasts are found in cavities, known as Howslip's lacunae, on the surface of bones. They remodel bone, by degrading and reabsorbing it, in response to growth or changing mechanical stress. Osteoclasts are large multinucleate cells. They contain a large proportion of rough endoplasmic reticulum (strands in cell), which manufactures and modifies proteins. To the left of the osteoclast are collagen fibres (purple), which are part of the bone's organic matrix. Magnification: x 5000 when printed at 10 centimetres wide.