Hint: The hepatic portal system is the venous system consisting of the hepatic portal vein and its tributaries. It is a part of the filtration system of the body. Its principal function is to provide de-oxygenated blood.
> Option A is incorrect. Kidneys are the main responsible for disposing of through our urine of waste products, drugs, and toxins. Therefore, no substances are transported from the kidney to the liver whereas vice-versa transport is possible.
> Option B is incorrect. The liver is an organ that produces waste products from the body, such as urea, which is produced when the excess amino acids are broken down. Too much urea is toxic, so the body needs to rid itself of it. Using the circulatory system, the area is transported from the liver into the kidneys.
> Option C is correct. The portal system starts at the digestive system's capillaries and venules. It collects venous blood from the lower oesophagus, stomach, duodenum, jejunum, ileum, colon, spleen, and passes it through the portal vein to the liver. The portal blood thus contains the substances that are absorbed by the digestive tract.
> Option D is incorrect. The supply of blood to the liver comes through the hepatic artery which delivers highly oxygenated blood from the lungs. Once this blood has been deoxygenated and processed by the liver, it is transported to the central hepatic vena of the liver. Then it leaves the liver and travels toward the heart.
Hence, The correct answer is option (C).
Note: Nearly 75% of total hepatic blood flow is through the portal vein, with the rest coming from the proper hepatic artery. The hepatic system is important because it collects blood from the intestine and passes it to the liver, the center for many chemical reactions related to food absorption into the body and substance control.