Basic structure of a Glomerulus.

The visceral epithelium (podocytes) is an intrinsic part of the capillary wall, whereas the parietal epithelium lines Bowman space

The glomerular capillary wall is the filtration unit and consists of the following

A thin layer of fenestrated endothelial cells

A glomerular basement membrane (GBM) with a thick, electron-dense central layer, the lamina densa, and thinner, electron-lucent peripheral layers, the lamina rara

The visceral epithelial cells (podocytes), structurally complex cells that possess interdigitating processes. Adjacent foot processes are separated by 20- to 30-nm-wide filtration slits

supported by mesangial cells lying between the capillaries, these cells are contractile and are capable of proliferation, of laying down both matrix and collagen, and of secreting a number of biologically active mediators

glomerular barrier function, discriminates among protein molecules depending on their size (the larger, the less permeable), their charge (the more cationic, the more permeable), and their conformation.