Labels:daily OCR: CORTEX HE CORTEX is one of three distinct sections that make up each kidney It is also called the renal cortex renal" means kidney) The cortex the darker- colored outer part of each kidney Ir has grainy texture because contains small blood vessels Blood travel into the kidneys in large blood vessels called renal arteries. cortex these arteries split up into many smaller vessels. or capillaries, which lead knot of tightly -coiled capillaries. from this knot that the waste materials that make up urine are filtered from the blood. travels thar