Confidence votes 180. The renal cortex is the part of the kidneys which mostly consists of nephrons and blood vessels. Its function is to filter blood and to remove the waste products inside the body.Nephrons are the basic functional units of the kidneys. The process of blood filtration starts in the renal cortex which is referred to as the urine manufacturing facility and contains the functional units of the kidneys know … n as nephrons. Each nephron is supplied with blood from the renal artery via its own individual afferent arteriole.