Glomerular capillary wall, consisting principally of a fenestrated endothelium, a basement membrane, and epithelial foot processes. The foot processes form filtration slits spanned by slit diaphragms. Also shown is the endothelial cell coat, or glycocalyx. Some approximate dimensions are (, ): minimum diameter of fenestra, 30 nm; GBM thickness, 200–400 nm (depending on species); width of filtration slit, 40 nm. The glycocalyx thickness is uncertain. Figure is not drawn to scale.