Anatomy and Physiology II Practice Test

The kidneys receive approximately what percentage of the total blood pumped by the heart each minute?

1. 10%

2. 15%

3. 20%

4. 25%

The correct answer is: 20%

The kidneys receive approximately 20% of the total blood pumped by the heart each minute, which is crucial for their function in filtering and regulating the body's fluids and electrolytes. Since the heart pumps about 5 liters of blood per minute at rest, the kidneys filter roughly 1 liter of that volume, highlighting their critical role in maintaining homeostasis. This significant blood supply ensures that the kidneys can efficiently perform their processes of filtration, reabsorption, and secretion, ultimately contributing to the regulation of blood pressure, electrolyte balance, and waste excretion. Options indicating 10%, 15%, or 25% do not accurately reflect the proportion of cardiac output directed to the kidneys, as those numbers either underestimate or overestimate the actual volume. Thus, recognizing that 20% is the correct answer illustrates an understanding of the kidneys' importance in the circulatory and excretory functions of the body.