Basalmembrania

Basalmembrania is a term that appears in some texts to denote the basal membrane, a specialized extracellular matrix layer that underlies epithelial and endothelial tissues and separates them from the underlying connective tissue.

The basal membrane, or basalmembrania in some usages, consists of two main components: the basal lamina, secreted by epithelial cells, and the reticular lamina, produced by the underlying stroma. Its primary molecular constituents include laminin, type IV collagen, nidogen (entactin), and proteoglycans such as perlecan.

Function and location: It lines almost all epithelia and endothelial linings, and also forms the glomerular basement membrane in the kidney. It provides mechanical support, acts as a selective filtration barrier, and mediates cell adhesion, polarity, differentiation, and migration through interactions with integrins and other receptors. It also serves as a scaffold for tissue repair.

Clinical relevance: Abnormalities or damage to basement membranes are implicated in diseases such as Goodpasture syndrome (autoantibodies against type IV collagen in kidney and lung), Alport syndrome (COL4 gene mutations affecting the glomerular basement membrane), and various cancers, where basement membrane degradation by proteases facilitates invasion. Diabetes can cause thickening of basement membranes, notably in the kidney and retina.

Terminology: The term basalmembrania is not standard in contemporary anatomy; basement membrane and basal lamina are the preferred terms. In some languages or historical texts, basalmembrania may be used to refer to the same structure.

See also: basement membrane, basal lamina, extracellular matrix, epithelial-mesenchymal transition.