The glomerulus is a tuft of capillaries inside Bowman’s capsule. Blood pressure forces fluids across it selectively permeable membrane (glomerular filtration). The resulting glomerular filtrate in Bowman’s capsule is plasma without cells or proteins.
The glomerular membrane is a specialized filtration barrier composed of endothelial cells, basal lamina, and podocytes. The endothelial cells of the glomerulus are fenestrated capillaries (with pores) that prevent filtration of cells. Filtration slits are formed by podocytes and the basal lamina. They keep large proteins out of the filtrate.
The volume filtered per unit time (typically, 125 ml/min). is the glomerular filtration rate (GFR). GFR is autoregulated: it remains relatively constant over wide range of systemic blood pressure (BP).
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