Effective filtration pressure in glomerulus is maintained due to

The glomerulus is a capillary network within the Bowman's capsules. Blood enters glomerular capillaries through afferent arterioles and leaves through efferent arterioles. The diameter of the afferent arteriole is much more than that of efferent arteriole. This increases the volume of blood in the glomerulus and increases the filtration rate.