In some types cells, the cell
presents differentiations that
necessary for the functions
of the . The main differentiations
the microvilli and structures for
reinforcement adhesion or union
cells (cell junctions).

are multiple external
of the membrane
glove fingers. This is
found in of tissues where is
advantageous to the size of
surface area in with the
exterior, example, in the
(intestinal) epithelium for of
nutrients.

Membrane for
reinforcement of between cells
occur in epithelial tissues
the need for and
impermeability requires to be
“glued” neighboring cells. These
scan be interdigitations,
, tight junctions (zonula
), zonula adherens (adherens
) and gap junctions.