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The portal vein is not a true vein, because it conducts blood to capillary beds in the liver and not directly to the heart. It is a major component of the hepatic portal system , one of three portal venous systems in the human body; the others being the hypophyseal and renal portal systems.
The hepatic artery provides 30 to 40% of the oxygen to the liver, while only accounting for 25% of the total liver blood flow. The rest comes from the partially deoxygenated blood from the portal vein. The liver consumes about 20% of the total body oxygen when at rest. That is why the total liver blood flow is quite high, at about 1 litre a ...
The human hepatic portal system delivers about three-fourths of the blood going to the liver.The final common pathway for transport of venous blood from spleen, pancreas, gallbladder and the abdominal portion of the gastrointestinal tract [2] (with the exception of the inferior part of the anal canal and sigmoid colon) is through the hepatic portal vein.
The causes for portal hypertension are classified as originating in the portal venous system before it reaches the liver (prehepatic causes), within the liver (intrahepatic) or between the liver and the heart (post-hepatic). The most common cause is cirrhosis (chronic liver failure). Other causes include: [1] [10] [11] Prehepatic causes. Portal ...
Portal vein thrombosis (PVT) is a vascular disease of the liver that occurs when a blood clot occurs in the hepatic portal vein, which can lead to increased pressure in the portal vein system and reduced blood supply to the liver. The mortality rate is approximately 1 in 10.
The right hepatic vein is the longest and largest of all the hepatic veins. It drains the liver segments VI and VII in their entirety, and variably participates in the drainage of segments V and VIII; the extent of drainage of the latter two segments by the right hepatic veins as opposed to the middle hepatic vein and possible variant accessory veins determines the calibre of the right hepatic ...
In the developed world, the most common cause is liver cirrhosis. [4] Other causes include cancer, heart failure, tuberculosis, pancreatitis, and blockage of the hepatic vein. [4] In cirrhosis, the underlying mechanism involves high blood pressure in the portal system and dysfunction of blood vessels. [4]
Blood from the superior portion of the rectum normally drains into the superior rectal vein and via the inferior mesenteric vein to the liver as part of the portal venous system. Blood from the middle and inferior portions of the rectum is drained via the middle and inferior rectal veins.