Each of these organs contains about 1 million nephrons, which filter blood
Here's how the kidneys filter blood: Blood travels to each kidney through the 
renal ... the nephrons (pronounced: NEH-fronz)  1 million tiny filtering units in 
each... [DOC] [TLE] Your Kidneys and How They Work - WebMD [PAR] Your kidneys are bean-shaped organs, each about the size of your fist.