Question

Both hepatic and renal portal systems are found in
A. Fishes, amphibians, reptiles
B. Amphibians, reptiles, mammals
C. Reptiles, aves, mammals
D. Cyclostomes, fishes, amphibians

Answer 1

Hint: Lower vertebrates have two portal systems called the hepatic (liver) and renal (kidney) portal systems, which are the regions of the venous system that begin in capillaries in tissues and join to form veins.

Complete answer:
Arteries and veins have been named according to the organ to which they supply blood. Metabolic waste is distributed in the blood and can reach toxic levels if left to accumulate, while the kidneys are supplied through the renal arteries with waste-containing blood. The hepatic portal system is a network of veins that bring blood to capillaries in the liver from the capillaries of the stomach, intestine, spleen, and pancreas. It is a component of the filtration mechanism of the body. Its primary function is to carry deoxygenated blood to the liver to be further detoxified before it returns to the heart.

The system of veins in fish and amphibians that take blood from the tail or hind limbs is the renal portal system. Furthermore, this vein goes into the kidney and separates into capillaries to form a renal portal vein. Kidneys separate nitrogenous waste from this blood. Both hepatic and renal portal systems are found in the case of fishes, amphibians, and reptiles. But only hepatic portal systems are present in the case of mammals.

Hence, option A- Fishes, amphibians, reptiles is the correct answer.

Note: The kidneys remove metabolic waste from the blood to be safely excreted by transferring it to urine. The importance of the hepatic portal system is to store and metabolize nutrients from the digestive tract to the liver after a meal. The role of the renal portal system is to supply renal tubule blood when glomerular filtration is absent or downregulated.