Kidneys
Kidneys are the primary part of the excretory system. There are two kidneys, which are located on each side of your spine at the same level as the liver. The right piece is often a bit lower than the left one. They can be divided into 3 areas: the outer region called the renal cortex, the inner layer called the renal medulla, and the renal pelvis. The main roles of the kidneys are to filter the wastes and excess fluids from the blood and then eliminate them in the urine. [3]
