Question

In a frog, the hepatic portal vein is formed by
a. Gastric, intestinal and splenic veins
b. Gastric, renal and hepatic veins
c. Gastric, sciatic and subclavian veins
d. Gastric, femoral and anterior abdominal

Answer 1

Hint: There are two portal systems in frogs. They are the renal portal system and the hepatic portal system. The hepatic portal system of frogs has two main veins. They are the hepatic portal vein and the anterior abdominal vein.

Complete answer:
Let’s briefly talk about the two portal systems in frog, the renal portal system and the hepatic portal system.
> Renal portal system is a portal system that supplies blood to the renal tubules in the kidneys. Blood from each leg (hind limb) is collected by outer femoral vein and inner sciatic vein. In the abdomen, the femoral divides into the renal portal (dorsal) and pelvic vein (ventral). The sciatic vein joins the renal portal vein.

> The hepatic portal system has the hepatic portal vein and the anterior abdominal vein as mentioned in the hint part. The anterior abdominal vein is formed by the fusion of pelvic veins. It receives blood from the urinary bladder and ventral wall of the abdomen.
The hepatic portal vein is formed by the fusion of several branches from the spleen, stomach, pancreas and the intestine. It is made up of the following veins:

> Gastric veins (from stomach), pancreatic vein (from pancreas), duodenal vein (from duodenum), anterior mesenteric vein (from small intestine) and splenic vein (from the spleen). It is concerned with the carrying of blood from the alimentary canal along with the dissolved digested food materials to the liver.

Hence, the correct answer is option (A).

Note: The word hepatic refers to the liver. The importance of hepatic portal system is that the hepatic portal vein collects blood from the alimentary canal (intestine) and passes it to the liver where it breaks down the nutrients, balances it and also metabolizes some materials for easier use by the other parts of the body.