In hepatic portal circulation, what is the primary purpose of transporting blood through the portal vein?

• A. Portal circulation bypasses the liver's detoxification pathways.
• B. Immediate delivery of nutrients to the heart.
• C. Detoxification and nutrient processing before systemic distribution.
• D. Portal circulation delivers oxygenated blood to liver directly via portal.

Answer: (C)

Blood from the gut and spleen arrives at the liver through the portal vein so the liver can screen and process nutrients before anything enters the rest of the body. In the liver, hepatocytes perform first‑pass metabolism: they detoxify drugs and toxins, neutralize pathogens, and convert and store nutrients—making glucose, proteins, and fats available in controlled ways for distribution. This processing ensures that substances entering systemic circulation are balanced and safer for the body. The portal blood is nutrient-rich but relatively low in oxygen, which the hepatic artery supplies to support these metabolic tasks, with processed blood then leaving the liver into the systemic circulation.