Structure of the kidney, frontal section of a kidney and ureter. From the outside to the inside of the kidney, we find the fibrous capsule (in pink), the renal cortex (in degraded), the renal medulla formed by the renal pyramids (in light burgundy) separated by the renal columns. Each pyramid opens into a renal chalice (beige brown part in the center of the kidney). The calyces open into the pelvis which narrows to form the ureter which passes behind the renal vessels (renal vein and artery). At each end of the renal columns open the renal sinuses with vessels.