Osteoclasts Very large, multinucleated blood monocytes; ruffled border if active Located in depression of resorbed bone - Howship’s lacunae (aka resorption cavities) Function: bone resorption during bone growth and remodeling Digest collagen; dissolve calcium salt crystals Receptors for calcitonin (from thyroid gland) and for OSF (osteoclast-stimulating factor-1)