The need for a surface area suficiently large to accommodate
the volume helps explain the microscopic size of most
cells and the narrow, elongated shapes of others, such as
nerve cells. Larger organisms do not generally have larger
cells than smaller organisms they simply have more cells
(see Figure 6.7). A suf ciently high ratio of surface area to volume
is especially important in cells that exchange a lot of
material with their surroundings, such as intestinal cells.
Such cells may have many long, thin projections from their
surface called microvilli, which increase surface area without
an appreciable increase in volume.