has part has part characteristic of has modifier Abnormal renal morphology Abnormal renal medulla morphology The renal pyramids of the adult kidney resemble a cone with a broad base adjacent to the renal cortex and the narrow apex that is termed papilla. The adult renal medulla is made up of 10-18 pyramids. A pyramid consists of the medullary collecting ducts, loops of Henle, vasa recta (straight capillaries) and the interstitium. The main function of the medulla is to regulate concentration of the urine. The urine flows from the collecting ducts into the renal calyces and pelvis. morphology abnormal renal medulla