How do nephrons filter blood

in simple terms. like ur explaining to a 12 year old

nephrons are the basic functional and structural units of your kidneys. each kidney has roughly anywhere between 800,000 to 1 million nephrons in it. their main function is to regulate the concentration of water & other soluable substances (soluble is something that dissolve in water. example: water soluble vitamins) in the blood. it reabsorbs what your body needs and excretes the rest as urine. ( it keeps what your body needs & you pee out what you don't need). nephrons eliminate wastes from your body & also help keep your blood volume & blood pressure under control. there's a long complicated process of how all of this filtering is done & where it goes to get filtered but i've broken it down the best i can.
-hope this helps!

here . . this link has all the info you need:
http://thinkwell.mindbites.com/lesson/41…

I wouldn't want anyone to actually use the internet for what it's intended.