Question : Kidneys produce about 180 litres of filtrate per day, but the actual urine production is about 1.2 to 1.5 litres per day. How does this reduction take place?

Question : Kidneys produce about 180 litres of filtrate per day, but t

1.	Question : Kidneys produce about 180 litres of filtrate per day, but the actual urine production is about 1.2 to 1.5 litres per day. How does this reduction take place?
Answer» Solution :Though the glomerular FILTRATE is 180 litres per day, 99% of the amount is reabsorbed during the process of SELECTIVE REABSORPTION. Depending upon concentration gradient, there are two PROCESSES, passive transport or osmosis and active transport. Since the renal tubule is surrounded by peritubular capillaries, this absorption is rapid and as per concentration gradient. Similarly large amount of water is reabsorbed by renal tubule. In this way the REDUCTION of the filtrate takes place.