Glomerular basement membrane
The glomerular basement membrane of the kidney is the basal lamina layer of the glomerulus. The glomerular endothelial cells, the glomeular basement membrane, and the filtration slits between the podocytes perform the filtration function of the glomerulus, separating the blood in the capillaries from the filtrate that forms in Bowman's capsule. The glomerular basement membrane is a fusion of the endothelial cell and podocyte basal laminas, and is the main site of restriction of water flow. Glomeular basement membrane is secreted and maintained by podocyte cells. Layers. The glomular basement membrane contains three layers: The glomerular  membrane consists of mesangial cells, modified pericytes that in other parts of the body separate capillaries from each other. The podocytes adjoining them have filtration slits of diameter 25 nm that are formed by the pseudopodia arising from them. The filtration slits are covered by a diaphragm that includes the transmembrane protein nephrin.