As demonstrated by the multinucleated cell featured in this video, Madin-Darby ovine kidney epithelial cells tend to assume extremely flattened forms in culture. Broad lamellipodia usually encircle the peripheries of the cells, and small, narrow filopodia are periodically extended and contracted. Filopodia can perform both sensory and locomotive roles in the cells, whereas lamellipodia chiefly function in cell migration. MDOK cells, however, do not migrate as actively in culture as many other types of cells.

Cytoplasm is a viscoelastic material, demonstrating both viscous flow and elasticity. The composition of the material varies in different types of cells, as well as in different portions of a particular cell. Notice, during the high-speed playback of the time-lapse sequence the cytoplasm found at the periphery of the cell seems to behave differently than the cytoplasm in the central region of the cell. This is because the cytoplasm located just beneath the plasma membrane is rich in actin filaments, which play a key role in the formation of lamellipodia and other surface protrusions. In contrast, the cytoplasm in the central area of cell is more abundant with intermediate filaments and microtubules.

Morphologic differences in the cytoplasm of the MDOK cell reflect variations in composition. The cytoplasm in the inner compartment of the cell appears to move about in a fluid-like fashion, and numerous dynamic organelles are located within it. This form of cytoplasm is known as plasmasol or endoplasm. The peripheral cytoplasm, however, moves in a different fashion and is usually free from organelles. The material has a gelatinous consistency and is referred to as plasmagel or ectoplasm. Changes in the shape of a cell can cause cytoplasmic shifts that result in some plasmasol transforming into plasmagel and vice versa.