Raised blood pressure in the PORTAL VEIN entering the LIVER. This results in increased pressure in the veins of the oesophagus and upper stomach and these grow in size to form varices – dilated tortuous veins. Sometimes these varices rupture, causing bleeding into the oesophagus. The raised pressure also causes ?uid to collect in the abdomen and form ASCITES. The commonest reason for portal hypertension is cirrhosis (?brosis) of the liver (see LIVER, DISEASES OF). THROMBOSIS in the portal vein may also be a cause. Treatment requires the cause to be tackled, but bleeding from ruptured vessels may be stopped by injecting a sclerosant or hardening solution into and around the veins. Sometimes a surgical shunt may be done to divert blood from the portal vein to another blood vessel.... portal hypertension
A vein or collection of veins which ?nish at both ends in a bed of capillary blood vessels. An important example is the hepatic portal system, comprising the portal vein and its tributaries. Blood from the stomach, pancreas, spleen and intestines drains into the veins that join up to comprise the portal vein into the liver, where it branches into sinusoids.... portal system
The vein which carries to the LIVER, blood that has been circulating in many of the abdominal organs. It is peculiar among the veins of the body in that it ends by breaking up into a capillary network instead of carrying the blood directly to the heart – a peculiarity which it shares only with certain small vessels in the kidneys. The PORTAL SYSTEM begins below in the haemorrhoidal plexus of veins around the lower end of the rectum; from this point, along the whole length of the intestines, the blood is collected into an inferior mesenteric vein upon the left, and a superior mesenteric vein upon the right side. The inferior mesenteric vein empties into the splenic vein, and the latter, uniting with the superior mesenteric vein immediately above the pancreas, forms the portal vein. The portal vein is joined by veins from the stomach and gallbladder, and ?nally divides into two branches which sink into the right and left lobes of the liver. (For their further course, see LIVER).
The organs from which the portal vein collects the blood are the large and small intestines, the stomach, spleen, pancreas, and gall-bladder.... portal vein
This is a type of circulatory bypass used when substances in blood or fluid need to be kept out of the general flow. A portal system begins in capillaries and ends in capillaries, and nothing leaves it undocumented. The hypothalamus sends hormones into the portal system between it and the pituitary, and the pituitary responds to it by secreting its own hormones, but dissolving the hypothalamus ones. Blood that leaves the intestinal tract, spleen, and pancreas (partially) goes into the liver’s portal system and does not leave that organ until it has been thoroughly screened and altered.... portal circulation
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