portal circulation

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Related to Portal venous system: portal hypertension, portal circulation

por·tal cir·cu·la·tion

1. circulation of blood to the liver from the small intestine, the right half of the colon, and the spleen through the portal vein; sometimes specified as the hepatic portal circulation;
2. more generally, any part of the systemic circulation in which blood draining from the capillary bed of one structure flows through a larger vessel(s) to supply the capillary bed of another structure before returning to the heart; for example, the hypothalamohypophysial portal system.

portal circulation

Etymology: L, porta, gateway, circulare, to go around
the pathway of blood flow from the GI tract and spleen to the liver via the portal vein and its tributaries. Also called hepatic portal circulation.
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Portal circulation

por·tal cir·cu·la·tion

(pōr'tăl sĭr'kyū-lā'shŭn)
1. Circulation of blood to the liver from the small intestine, the right half of the colon, and the spleen through the portal vein; sometimes specified as the hepatic portal circulation.
2. More generally, any part of the systemic circulation in which blood draining from the capillary bed of one structure flows through a larger vessel(s) to supply the capillary bed of another structure before returning to the heart, e.g., the hypothalamohypophysial portal system.
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HEPATIC PORTAL CIRCULATION

portal circulation

1. Blood flow from the abdominal organs that passes through the portal vein, the sinusoids of the liver, and into the hepatic vein before returning to the heart from the inferior vena cava. This pathway permits the liver to process and to detoxify substances entering the body from the gastrointestinal tract.
2. A portal system between the hypothalamus and the anterior pituitary gland. The hypothalamus secretes releasing or inhibiting hormones into the blood; they are carried directly to the anterior pituitary and stimulate or inhibit secretion of specific hormones.
See: Hepatic Portal Circulation illustration
See also: circulation

circulation

movement in a regular or circuitous course, returning to the point of origin, as the circulation of the blood through the heart and blood vessels. See also circulatory system.

antegrade circulation
circulation in the normal direction of flow.
artificial circulation
is maintained in cardiopulmonary arrest by cardiac compression.
collateral circulation
circulation carried on through secondary channels after obstruction of the principal channel supplying the part.
coronary circulation
that within the coronary vessels, which supply the muscle of the heart.
cutaneous circulation
cutaneous vessels are innervated by sympathetic adrenergic vasoconstrictor fibers; vasodilation is an important mechanism for losing heat after the body has been warmed.
enterohepatic circulation
the cycle in which bile salts and other substances excreted by the liver in the bile are absorbed by the intestinal mucosa and returned to the liver via the portal circulation.
extracorporeal circulation
circulation of blood outside the body, as through a hemodialyzer or an extracorporeal circulatory support unit.
fetal circulation
circulation of blood through the body of the fetus and to and from the placenta through the umbilical cord. See also fetal circulation.
hepatic circulation
includes the hepatic arterial blood supply and the supply from the portal vein; drainage is via the hepatic veins to the caudal vena cava.
lymph circulation
see lymph.
maternal circulation
the circulation of the dam during pregnancy, including especially that of the uterus.
micro-circulation
neonatal circulation
circulation in the newborn immediately after birth; the umbilical vessels contract forcing blood into the fetal veins; the foramen ovale closes, the ductus arteriosus narrows and eventually closes at day 1 to 2 after birth.
ocular circulation
consists of the uveal and retinal blood vessels supported by the aqueous humor and vitreous body.
placental circulation
consists of the umbilical arteries, the vessels of the placenta proper and the umbilical veins; approximates the fetal corporeal circulation in volume.
portal circulation
a general term denoting the circulation of blood through larger vessels from the capillaries of one organ to those of another; applied especially to the passage of blood from the gastrointestinal tract, pancreas and spleen through the portal vein to the liver.
pulmonary circulation
the flow of blood from the right ventricle through the pulmonary artery to the lungs, where carbon dioxide is exchanged for oxygen, and back through the pulmonary vein to the left atrium. See also pulmonary circulation.
splenic circulation
flow of blood through the splenic artery and arterioles to either the capillaries, e. g. white pulp, or the highly permeable sinuses of the red pulp. Splenic venous blood drains into the portal vein and passes through the liver before re-entering the general circulation.
systemic circulation
the flow of blood from the left ventricle through the aorta, carrying oxygen and nutrient material to all the tissues of the body, and returning through the superior and inferior venae cavae to the right atrium.
circulation time
the time required for blood to flow between two given points. It is determined by injecting a substance into a vein and then measuring the time required for it to reach a specific site.

portal

1. an avenue of entrance; porta.
2. pertaining to an entrance, especially the porta hepatis.

portal-azygos anastomosis
a form of portacaval shunt with the portal vein bypassing the liver and emptying directly into the azygos vein.
portal biliary bacterial circulation
a continuous normal circulation of bacteria brought to the liver in the portal vein from the gut and excreted back into the gut via the biliary system.
portal canal
tissue space situated between three or more hepatic lobules; carries the blood and lymphatic vessels and connective tissue.
portal-caval
see portacaval.
portal circulation
circulation of blood from the capillaries of one organ to those of another; applied especially to the passage of blood from the gastrointestinal tract and spleen through the portal vein to the liver. See also circulatory system.
portal of entry
the pathway by which bacteria or other pathogenic agents gain entry to the body.
portal fibrosis
see biliary fibrosis.
portal hypertension
see portal obstruction.
portal obstruction
obstruction of portal venous blood flow through external pressure on the portal vein, by abscess or tumor or by hepatic fibrosis constricting the hepatic vascular bed, causes interference with digestion and absorption and eventually venous return so that ascites and diarrhea develop.
portal system
an arrangement by which blood collected from one set of capillaries passes through a large vessel or vessels and another set of capillaries before returning to the systemic circulation, as in the pituitary gland and liver.
Includes the hepatic portal system consisting of portal vein and its tributaries from the stomach, intestine, pancreas and spleen, the vessels into which the portal vein divides in the liver and the hepatic veins that enter into the caudal vena cava.
portal systemic shunt
see portacaval shunt.
portal triad
anatomically close association of interlobular bile duct, branches of hepatic artery and portal vein.
portal vascular anomalies
see portacaval anastomosis.
portal vein
a short, thick trunk formed by the union of the caudal mesenteric and splenic veins; at the porta hepatis, it divides into successively smaller branches, following branches of the hepatic artery, until it forms a capillary system of sinusoids that permeates the entire substance of the liver.
portal vein obstruction
acute, complete obstruction causes a syndrome similar to that of intestinal obstruction without signs suggesting liver involvement; partial occlusion causes shrinkage and eventual atrophy of the relevant section of the liver.
portal vein rupture
rare complication of epiploic foraminal herniation; sudden death from internal hemorrhage results.
portal venule absence
a congenital defect resulting in the development of multiple shunts within the liver, hepatoportal fibrosis and ascites, general immaturity and hepatic encephalopathy.
References in periodicals archive ?
Long term management requires decompression of the portal venous system.
He said that portal hypertension is a major complication of chronic liver disease and is manifested through an increase in the blood pressure within a system of veins called the portal venous system.
It usually develops secondary to infection in the drainage area of the portal venous system (1), (2).