What is the main purpose of the hepatic-portal circulation?

Answer 1

Hepatic Portal Circulation The veins of the hepatic portal circulation drain the digestive organs, spleen, and pancreas and deliver the blood to the liver via hepatic portal vein. As blood percolates through the liver, some of the nutrients are stored or processed in various ways for release to the general circulation. The liver in turn is drained by the hepatic veins that enter the inferior vena cava. The inferior mesenteric vein, draining the distal part of the large intestine, joins the splenic vein, which drains the spleen, pancreas and stomach. The splenic vein and the superior meseteric vein, which drains the small intestine and the proximal colon, unite to form the hepatic portal vein. The left gastric vein, which drains the lesser curvature of the stomach, drains directly into the hepatic portal vein. Hepatic Portal Circulation The veins of the hepatic portal circulation drain the digestive organs, spleen, and pancreas and deliver the blood to the liver via hepatic portal vein. As blood percolates through the liver, some of the nutrients are stored or processed in various ways for release to the general circulation. The liver in turn is drained by the hepatic veins that enter the inferior vena cava. The inferior mesenteric vein, draining the distal part of the large intestine, joins the splenic vein, which drains the spleen, pancreas and stomach. The splenic vein and the superior meseteric vein, which drains the small intestine and the proximal colon, unite to form the hepatic portal vein. The left gastric vein, which drains the lesser curvature of the stomach, drains directly into the hepatic portal vein.

Answer 2

The portal venous system is responsible for directing blood from parts of the gastrointestinal tract to the liver. Substances absorbed in the small intestine travel first to the liver for processing before continuing to the heart. Not all of the gastrointestinal tract is part of this system. The system extends from about the lower portion of the esophagus to the upper part of the anal canal. It also includes venous drainage from the spleen and pancreas. Many drugs that are absorbed through the GI tract are substantially metabolized by the liver before reaching general circulation. This is known as the first pass effect. As a consequence, certain drugs can only be taken via certain routes. For example, nitroglycerin cannot be swallowed because the liver would inactivate the medication, but it can be taken under the tongue and thus is absorbed in a way that bypasses the portal venous system. Blood flow to the liver is unique in that it receives both oxygenated and deoxygenated blood. As a result, the partial pressure of oxygen (pO2) and perfusion pressure of portal blood are lower than in other organs of the body. Blood passes from branches of the portal vein through cavities between "plates" of hepatocytes called sinusoids. Blood also flows from branches of the hepatic artery and mixes in the sinusoids to supply the hepatocytes with oxygen. This mixture percolates through the sinusoids and collects in a central vein which drains into the hepatic vein. The hepatic vein subsequently drains into the inferior vena cava. Large veins that are considered part of the portal venous systemare the: * Hepatic portal vein * Splenic vein Roughly, the portal venous system corresponds to areas supplied by the celiac trunk, the superior mesenteric artery, and the inferior mesenteric

Answer 3

That probably means the portal venous system of the abdomen. Here you receive the blood from the gastrointestinal tract. In this case the blood is rich in nutrition. Such nutrition rich blood is presented to liver for the metabolism. Other wise the blood would have diluted the nutrition and part of the cardiac out put would have gone to liver for metabolism.

Answer 4

Upon uptake, most solutes will be exported on the other side of the mucosal cells and then find themselves in the blood stream. A peculiarity of the intestines consists in the fact that all blood drained from them is first passed on to the liver via the portal vein before being released into the general circulation. This serves a twofold purpose:

1. It gives the liver a chance to take excess amounts of substrates (glucose, amino acids) out of circulation and to store and process them. This helps to maintain stable blood nutrient concentrations, which is important for the well-being of the more sensitive and fastidious cells in the rest of the body.
2. The bacteria in the large intestine produce ammonia and other toxic metabolites, which are cleared by the liver. In patients with liver failure, these toxic metabolites spill over into the systemic circulation, which will among other things lead to disturbances of cerebral function.

The liver has a particular tissue structure that enables it to exchange solutes with the blood very efficiently. While in most organs the blood is contained in blood vessels with clearly defined boundaries and walls, the liver has a sponge-like structure that permits direct contact of the blood plasma with the liver cells.

Answer 5

With the liver being the metabolic brain, the hepatic portal system allows the liver to get a first chance at making metabolic decisions on whether the body is in the well-fed or fasting states. Subsequent insulin or glucagon secretion will then put the body into either a glucose sparing or glucose storing mode

Answer 6

Hepatic portal circulation is mainly responsible for blood to be available for helping in the digestive process.

Answer 7

In human anatomy, the hepatic portal system is the system of veins comprising the hepatic portal vein and its tributaries.

Answer 8

It allows the liver to process and detoxify nutrient-rich blood from most abdominal organs.