Peruskalvo

Peruskalvo, in English commonly called the basement membrane, is a thin, specialized sheet of extracellular matrix that separates epithelial or endothelial cells from the underlying connective tissue. It provides structural support and helps organize tissues by anchoring cells and guiding their behavior.

The basement membrane typically consists of two layers: the basal lamina and the reticular lamina. The basal lamina is produced mainly by epithelial or glial/muscle cells and contains proteins such as laminins, type IV collagen, nidogen (entactin), and heparan sulfate proteoglycans like perlecan. The reticular lamina is synthesized by underlying connective tissue cells and includes different collagens and proteoglycans. Together, these layers form a continuous, dynamic barrier and scaffold found beneath most epithelial and endothelial surfaces, as well as surrounding certain muscle fibers and Schwann cells.

Functions of the peruskalvo include providing mechanical support, regulating cell adhesion, polarity, and migration, and acting as a selective barrier in processes such as filtration in the kidney glomerulus and the alveolar-capillary membrane in the lungs. It also participates in signaling that influences cell differentiation and tissue repair after injury.

Development and turnover are dynamic: cells synthesize basement membrane components, which are remodeled by enzymes such as matrix metalloproteinases during development and wound healing. Disruption or genetic defects in basement membrane components can lead to diseases, including skin blistering disorders like epidermolysis bullosa and kidney diseases such as Alport syndrome, where the integrity of type IV collagen-containing membranes is compromised.

In summary, the peruskalvo is a crucial, multifunctional component that supports, filters, and coordinates cells within many tissues.