Also found in: Dictionary, Thesaurus, Medical, Legal.
basal membrane[′bā·səl ′mem‚brān]
in vertebrate animals and man, the boundary film between the epithelium (or endothelium) and underlying loose connective tissue from which it is formed. The basal membrane consists of a diffuse substance and the fibers embedded in it. It serves to strengthen the epithelial layer of cells and prevents its cells from shifting deep into the connective tissue. Impairment of the basal membrane causes the epithelium to grow into the underlying connective tissue (for example, in chronic inflammation and malignant degeneration). The fact that the basal membrane is permeable to some metabolites indicates that it plays a definite part in metabolism.