The vessels form the hepatic portal vein.

The hepatic portal vein is a blood vessel that carries blood from the gastrointestinal tract, spleen, and pancreas to the liver. It is formed by the merging of the superior mesenteric vein and the splenic vein behind the neck of the pancreas. The hepatic portal vein plays a crucial role in transporting nutrients, toxins, and other substances absorbed from the intestines to the liver for processing and detoxification.

- Gastric vein
- Splenic vein
- Superior mesenteric vein
- Inferior mesenteric vein