Final answer:
The pathway of blood from the aorta to the small intestine to the liver and back to the inferior vena cava is as follows: oxygenated blood is pumped from the left ventricle to the aorta, which carries it to the head and upper extremities, and down to the abdomen. From there, blood from the small intestine enters the hepatic portal system and is taken to the liver for processing. After processing, the blood returns to the heart via the hepatic vein and the inferior vena cava.
Step-by-step explanation:
The pathway of blood from the aorta through the small intestine to the liver and back to the inferior vena cava is as follows:
- Oxygenated blood is pumped from the left ventricle into the aorta, the body's largest artery.
- The aorta carries the blood to the arteries branching off to the head and upper extremities, and continues down through the abdomen.
- The blood from the small intestine, where most absorption occurs, is collected by veins that empty into the hepatic portal system.
- The hepatic portal vein carries the blood to the liver, where nutrients are processed or stored.
- After processing in the liver, the blood circulates back to the heart through the hepatic vein to the inferior vena cava.
This pathway ensures that all blood from the small intestine passes through the liver, explaining why the liver is the most common site for the metastasis of cancers originating in the alimentary canal.