Answer
The basement membrane of the epithelium which lies below the basal surface of the cells has two layers: the basal lamina nearer the cells and the lower reticular layer. Laminin proteins in the basal lamina bind tightly to integrins in hemidesmones of the overlying epithelia, which is thus anchored and supported. In addition to stabilizing the epthelial cells, the basement membrane serves the epithelium in the following ways: it provides a surface along which epithelial cells migrate in growth and wound healing processes; it selectively restricts the movement of large molecules between epithelium and connective tissue; finally basement layer of kidney epithelial cells filter substances from blood.
Work Step by Step
The basal lamina of he basement membrane is closest to the basal layer of epithelial cells. It is secreted by the epithelium and contains the proteins laminin, and collagen, as well as glycoproteins and proteoglycans. It is the binding between the integrins of the epithelial hemdesmones and the laminins of of this layer that physically stabilizes the epithelial layer of cells.
