This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
What is glomerular filtration rate? March 2008 
Select and explain. 
A. 100 ml/min, B. 125 ml/min, C. 150 ml/min, D. 175 ml/ min
B: 125 ml/min
Answer: B: 125 ml/min 
Explanation: Ans. B: 125 ml/minThe GFR in an average-sized normal man is approximately 125 ml./min.Its magnitude correlates fairly well with surface area, but values in women are 10% lower than those in men even after correction for surface area. A rate of 125 mL/ min is 7.5 L/h, or 180 L/d, whereas the normal urine volume is about 1 L/d. Thus, 99% or more of the filtrate is normally reabsorbed. At the rate of 125 mL/ min, the kidneys filter in 1 day an amount of fluid equal to 4 times the total body water, 15 times the ECF volume and 60 times the plasma volume.