Question

how do kidneys filter blood ?

Answer 1

Kidneys are always working they filter blood mixed with waste product that waste product goes to the bladder and the blood works its way back to the heart.

Answer 2

http://kidney.niddk.nih.gov/kudiseases/pubs/yourkidneys/#kidneys

Answer 3

The kidney contains numerous units called nephrons, these have special components that are called Glomeruli (glomerulus singular) which are supplied by a huge network of blood vessels. The mechanism by which the glomerulus filters blood is complex it involves many ion channels, active pumps, ect . here is an overall picture to what happens ..