How is blood filtrated by the glomeruli in the kidneys?

Blood enters the glomerulus from the afferent arteriole at a very high pressure, so the hydrostatic pressure forces the contents of the blood out of the blood vessels, into the Bowman's capsule. However, a filtration barrier is formed by the fenestrated capillaries of the endothelium (which means that the endothelium contains pores which some molecules can pass through), the basement membrane and the podocytes, which are the cells which make up the walls of the Bowman's capsule and wrap around the capillaries of the glomerulus. This means that only smaller molecules are filtered out, whereas larger molecules (such as plasma proteins) and blood cells remain, in a highly concentrated solution.