Answer:
At the base of the epithelial tissues is a layer of extracellular tissue that is known as the basement membrane. Whose main function is sustain and variable thickness.
Its layers are:
Basal lamina = composed in turn, by the lucida lamina and the dense lamina. Adipocytes, muscle cells and nerves are often found at the level of this lamina.
Reticular lamina = composed of denser and reticular fibers as well as a large number of proteins. It is also known as external lamina.