our urinary system produces and diposes of urine in four major processes shownin figure 25.7 first duringfiltration the pressure of the blood forces water and other small molecules through a capillary wall intothe start of a kidney tubule forming filtrate two system produces the refine the filtrate. in rebsorption water and valuable solute including glucose salt other ions and amino acids are reclaimed from the filtrate and return to the blood in secreation subtances in the blood are transorted into the filtrate when is an excess of h inthe blood