Final answer:
The kidneys receive a significant portion of cardiac output via the renal arteries, which branch from the aorta and further subdivide to supply the nephron's capillary networks in the kidneys.
Step-by-step explanation:
The kidneys receive 25% of the total cardiac output each minute most directly via the renal arteries, which branch out from the aorta.
The renal arteries play a critical role in the renal circulation, ensuring the kidneys perform their main function of filtering waste from the blood. These arteries branch directly from the aorta, the body's largest artery. Even though each kidney is relatively small, they are heavily supplied with blood, receiving about 10% of the heart's total output individually.
As the renal arteries enter the kidneys, they further divide into smaller arteries -- segmental, interlobar, arcuate, and cortical radiate arteries, which lead to the network of capillaries that supply the functional units of the kidneys, the nephrons.
After the filtration process, the renal veins collect the deoxygenated and cleansed blood, which they then carry back to the inferior vena cava. The kidneys' vasculature is designed to maximise their efficiency in filtering and purifying the blood, reabsorbing water and solutes through a secondary capillary bed encompassing the nephron's tubular system.