Final answer:
The high volume of 180 liters of filtrate produced daily by the kidneys results in only 1.5 liters of urine because the kidneys reabsorb 99% of the filtrate. This process is regulated by the glomerular filtration rate (GFR) and is crucial for maintaining fluid balance and excreting waste while preventing dehydration.
Step-by-step explanation:
About 180 liters of filtrate is produced daily by the kidneys due to the process of glomerular filtration, which is the rate at which the kidneys filter blood. Though such a high volume of filtrate is produced, only 1.5 liters of urine is excreted. This discrepancy is because around 99 percent of the filtrate is reabsorbed back into the bloodstream. The kidneys efficiently reclaim water, electrolytes, and other substances essential to the body, while excreting metabolic waste products like creatinine, urea, and uric acid in urine. The glomerular filtration rate (GFR) and regulation of water output are crucial for maintaining fluid balance and clearing wastes from the body while preventing dehydration and overload.
The process involves a delicate balance between forces known as hydrostatic pressure and colloid osmotic pressure, with the former generally being greater, enabling filtration to occur. Kidneys function normally across a variety of blood pressures due to autoregulatory mechanisms.