Overview of Kidney Disorders in Children How do the kidneys
work? The body takes nutrients from food and converts them to
energy. After the body has taken the food that it needs, waste
products are left behind in the bowel and in the blood. The
kidneys and urinary system keep chemicals, such as potassium and
sodium, and water in balance by removing a type of waste, called
urea, from the blood. Urea is produced when food containing
protein, such as meat, poultry, and certain vegetables, are
broken down in the body. Urea is carried in the bloodstream to
the kidneys. Click Image to Enlarge Two kidneys, a pair of
purplish-brown organs, are located below the ribs toward the
middle of the back. Their function is to: Remove liquid waste
from the blood in the form of urine Keep a stable balance of
salts and other substances in the blood Produce erythropoietin,
a hormone that aids the formation of red blood cells Click Image
to Enlarge The kidneys remove urea from the blood through tiny
filtering units called nephrons