Figure 3. Transmission electron micrographs of osteoclasts after incubation on bone slices.

A, B: osteoclast shows clear zone (CZ) at extreme left of field, and extensive ruffled border (RB) to centre and right. Between is an area, shown at higher magnification in B, in which the surface of the cell shows no membrane folds, and in which there is close approach of vesicles to the apical surface. C: view of part of an osteoclast in which zones of membrane ruffles are separated by a region of fold-free membrane. Secondary lysosomes are present just above this fold-free region. Bar 2 µm (A) and 1 µm (B, C).