# The Hepatic Portal System --- The **hepatic portal system**, sometimes called **splanchnic circulation** is a system of [[blood vessels|portal veins]] that bring all of the nutrient-full blood from the [[digestive system|gastrointestinal tract]], as well as the red blood cell recycling of the [[spleen]] straight to the [[liver]]. When blood travels down from the heart into the digestive system, that blood is oxygen-rich but nutrient-poor. Part of that blood is delivered directly to the liver via the hepatic artery, the rest goes to the digestive organs like the stomach, spleen, and intestines, etc. All the micronutrients (amino acids, simple sugars) that get broken down there enter into the portal vein. This is a large portion of the blood entering the liver, and it's oxygen-poor but nutrient-rich. Once at the liver it is filtered in the [[liver|lobules]] and drained back out into the hepatic veins. ![[hepatic portal system.png]] Once filtered, the blood is released back into the regular [[cardiovascular system]] via the [[blood vessels#The Great Vessels|inferior vena cava]]. ## Portal Hypertension **Portal hypertension** is [[hypertension]] that develops within the hepatic portal system. Although this is not the only portal system in the body (for example the [[pituitary gland#Anatomy|hypophyseal portal system]] between the hypothalamus and pituitary gland), but it is definitely the largest by a huge factor, and the other ones are too small to risk developing hypertension in any meaningful way. Portal hypertension is pretty dangerous, and can lead to conditions such as: - [[esophageal varices]] - the backup of blood can cause [[collateralization]] to form, which can result in EV. - [[ascites]] - [[hepatic encephalopathy]] - caput medusae - like [[varicose veins]] on the abdomen ### TIPS A **transjugular intrahepatic portosystemic shunt** or **TIPS** procedure can be done, where a shunt is placed inside the body of the liver connecting the portal vein to the hepatic vein directly. This acts as a pressure release and allows that backed up blood to bypass the liver. This relieves the portal hypertension, but unfortunately can worsen any [[hepatic encephalopathy]] seeing as ammonia in the blood can bypass the liver. ![[TIPS.png]] ___