Which organ is primarily supplied by the main portal vein?

The primary organ supplied by the main portal vein is the liver. The main portal vein is formed by the convergence of the superior mesenteric vein and the splenic vein, and its major function is to transport nutrient-rich blood from the gastrointestinal tract and spleen to the liver. This blood contains products absorbed from digested food, as well as substances that need to be metabolized or detoxified by the liver before entering systemic circulation.

The liver plays a crucial role in various metabolic processes, including the regulation of blood glucose levels, the synthesis of proteins, and the detoxification of harmful substances. The portal vein ensures that these substances are delivered directly to the liver for processing.

In contrast, the spleen, pancreas, and gallbladder do not receive their primary blood supply from the main portal vein. The spleen, for instance, receives its blood supply primarily from the splenic artery, while the pancreas is supplied by various pancreatic arteries. The gallbladder is mostly supplied by the cystic artery, which branches off from the right hepatic artery. Therefore, the liver stands out as the primary organ receiving blood directly from the main portal vein.