How much blood passes through the kidney every minute?

• A. 800 mL
• B. 1200 mL
• C. 1600 mL
• D. 200 mL

Answer: (B)

Renal blood flow is the amount of blood reaching the kidneys each minute. In a healthy adult, cardiac output is about 5 liters per minute, and the kidneys receive roughly one-fifth of that. That puts renal blood flow in the neighborhood of 1,000–1,300 mL per minute, with 1,200 mL/min being a common rounded value used in physiology texts. So the best answer reflects about 1,200 mL of blood passing through the kidneys each minute.

Remember this is different from the filtrate produced (glomerular filtration rate, about 125 mL/min) or the urine output. The other options fall outside the typical range for renal blood flow.