Nutrients enter the liver primarily through the portal vein.
The Liver's Blood Supply: A Dual System
The liver receives blood from two main sources, each with a distinct purpose:
- Hepatic Artery: Supplies oxygen-rich blood to the liver.
- Portal Vein: Transports nutrient-rich blood from the intestines. This is the primary route for nutrients to enter the liver.
According to information provided, "nutrients from the intestines come through the portal vein".
Nutrient Delivery via the Portal Vein
The portal vein collects blood directly from the digestive organs (intestines, stomach, spleen, and pancreas) and delivers it to the liver. This blood is rich in:
- Carbohydrates (glucose): Absorbed from digested food.
- Amino acids: Derived from protein digestion.
- Fats (lipids): Although some fats enter the lymphatic system first, many are processed and enter the bloodstream for delivery to the liver.
- Vitamins and minerals: Absorbed from the diet.
Sinusoids: Where the Magic Happens
Once in the liver, the blood from the portal vein (and hepatic artery) flows through specialized blood vessels called sinusoids. These sinusoids allow the liver cells (hepatocytes) to come into close contact with the nutrient-rich blood, enabling them to:
- Process and metabolize nutrients: The liver plays a central role in regulating blood sugar, synthesizing proteins, storing vitamins, and detoxifying harmful substances.
- Store excess nutrients: For later use, the liver can store glucose as glycogen and fats as triglycerides.
- Release nutrients into circulation: When the body needs energy, the liver can release glucose back into the bloodstream.
