In frog, the renal portal system transports the blood from

Renal portal system transports blood from lower parts of the body to kidneys. Renal portal system in frog consists of one pair of renal portal veins, each one formed by the union of femoral vein and sciatic vein. It collects blood from leg region and drains it into kidney. It also collects blood from dorsal part of lumbar region through dorso-lumbar vein. Renal portal system helps in blood filtration by draining it into kidney which filters the blood.