Question

Both hepatic and renal portal systems are found in

• A. Amphibians, Reptiles, Mammals
• B. Reptiles, Aves, Mammals
• C. Cyclostomes, Fishes, Amphibians
• D. Fishes, Amphibians, Reptiles

Answer 1

The correct option is D Fishes, Amphibians, Reptiles

The renal portal system is derived from the posterior cardinal veins. Blood from the posterior part of the body flows into the renal portal veins, which passes into the caudal vena cava. The renal portal system is found only in fishes, amphibians, reptiles and birds. Thus, mammals have no renal portal system. All that remains in mammals is the azygous vein, which is an unpaired vein that drains most of the intercostal space on both sides of the mammalian thorax.