Describe the filtration in the kidneys.

Stage 1)renal artery carries oxygenated blood to kidney filtered at high pressure at the start of the nephrons which reabsorbs useful small molecules: glucose, salt ions and water aiding ultrafiltration big molecules like protien can't fit Stage 2)Selective reabsorbtion of molecules which the body needs back into bloodstream as much: glucose, water and ions the body needs Stage 3)molecules not selectively reabsorbed: urea, excess water & ion excreted