basement membrane cellular_component A collagen-containing extracellular matrix consisting of a thin layer of dense material found in various animal tissues interposed between the cells and the adjacent connective tissue. It consists of the basal lamina plus an associated layer of reticulin fibers. GO:0005605 GO:0005604 Wikipedia:Basement_membrane lamina densa basal lamina basement lamina GO:0008003 Note that this term has no relationship to 'membrane ; GO:0016020' because the basement membrane is not a lipid bilayer. collagen-containing extracellular matrix