MICROANATOMY

Detailed explanation-1: -Epithelial cell polarity Page 27 Epithelia are polarized with apical and basal surfaces. Epithelial have two functionally and biochemically different surfaces. The apical faces external environment or lumen of a tube where it is often involved in absorption or secretion.

Detailed explanation-2: -Simple squamous epithelial cells are thin and flat (the thinnest of all epithelial cell-types), which allows them to have a large surface area that is exposed to the lumen on one side (the apical surface), and to the basement membrane (i.e. basal lamina) on the other (the basolateral surface; Figure 1).