ECMの特殊な形態である基底層

The basement membrane or basal lamina is a specialized form of extracellular matrix or ECM. Its organization and function depend on the cell type to which it is attached.

For example, at the neuromuscular junction, the basal lamina surrounds the muscle cells, separating them from the nerve cells. In contrast, the basal lamina in the epithelium is placed below the cells, separating them from the underlying connective tissue.

In the kidney glomerulus, it is present between sheets of endothelial and epithelial cells, acting as a molecular filter preventing the passage of macromolecules from the blood into the urine.

The basal lamina is mainly composed of type IV collagen, and glycoproteins such as  laminins, entactin and perlecan.

These proteins together act as a bridge by linking the cells to the ECM of the connective tissue.