Ryan P. Smith, MD and Christine Hill-Kayser, MD The Abramson
Cancer Center of the University of Pennsylvania Last Modified:
February 25, 2008 The kidneys are two bean-shaped organs that
are located in the back of the abdomen, and that have many
important functions essential for life. Among the most important
are filtrating the blood, removing waste products from the blood
and ensuring that the electrolytes within the blood are
correctly balanced. In addition, the kidneys produce
erythropoietin, a hormone responsible for the production of (the
oxygen carrying) red blood cells. Each of the kidneys can be
divided into two main functional parts. The outer region of the
kidney is called the cortex The cortex consists of a series of
tubes (called collecting tubules) and is responsible for the
filtration of blood.. The inner region of the kidney is called
the renal pelvis. The renal pelvis contains medullary pyramids
that collect the filtrate (urine) from collecting tubules in the
cortex and send it through the uret