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Hepatic portal vein

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Title: Hepatic portal vein  
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Hepatic portal vein

Hepatic portal vein
The portal vein and its tributaries. It is formed by the superior mesenteric vein, inferior mesenteric vein, and splenic vein. Lienal vein is an old term for splenic vein.
Details
Latin vena portae hepatis
Drains from
Gastrointestinal tract, spleen, pancreas
Source
splenic vein, superior mesenteric vein, inferior mesenteric vein
Drains to
liver sinusoid
Identifiers
MeSH A07.231.908.670.567
Dorlands
/Elsevier
v_05/12851372
Anatomical terminology

The hepatic portal vein is a blood vessel that conducts blood from the gastrointestinal tract and spleen to the liver. This blood is rich in nutrients that have been extracted from food, and the liver processes these nutrients; it also filters toxins that may have been ingested with the food. 75% of total liver blood flow is through the hepatic portal vein, with the remainder coming from the hepatic artery proper. The blood leaves the liver to the heart in the hepatic veins.

The hepatic 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 only two portal venous systems in the body – with the hypophyseal portal system being the other.

The hepatic portal vein is usually formed by the confluence of the superior mesenteric and splenic veins and also receives blood from the inferior mesenteric, gastric, and cystic veins.

Conditions involving the hepatic portal vein cause considerable illness and death. An important example of such a condition is elevated blood pressure in the hepatic portal vein. This condition, called portal hypertension, is a major complication of cirrhosis.

Contents

  • Structure 1
    • Portacaval anastomoses 1.1
    • Accessory hepatic portal veins 1.2
  • Function 2
  • Clinical significance 3
    • Portal hypertension 3.1
    • Pylephlebitis 3.2
  • History 4
  • References 5
  • Additional images 6
  • External links 7

Structure

Tributaries of the hepatic portal vein[1]

Measuring approximately 8 cm (3 inches) in adults,[2] the hepatic portal vein is located in the right upper quadrant of the abdomen, originating behind the neck of the pancreas.[3]

In most individuals, the hepatic portal vein is formed by the union of the superior mesenteric vein and the splenic vein.[4] For this reason, the hepatic portal vein is occasionally called the splenic-mesenteric confluence.[3] Occasionally, the hepatic portal vein also directly communicates with the inferior mesenteric vein, although this is highly variable. Other tributaries of the hepatic portal vein include the cystic and gastric veins.[1]

Immediately before reaching the liver, the portal vein divides into right and left. It ramifies further, forming smaller venous branches and ultimately portal venules. Each portal venule courses alongside a hepatic arteriole and the two vessels form the vascular components of the portal triad. These vessels ultimately empty into the hepatic sinusoids to supply blood to the liver.[1]

Portacaval anastomoses

The portal venous system has several anastomoses with the systemic venous system. In cases of portal hypertension these anastamoses may become engorged, dilated, or varicosed and subsequently rupture.

Accessory hepatic portal veins

Accessory hepatic portal veins are those veins that drain directly into the liver without joining the hepatic portal vein. These include the paraumbilical veins as well as veins of the lesser omentum, falciform ligament, and those draining the gallbladder wall.[3]

Function

The hepatic portal vein and hepatic arteries form the liver's dual blood supply. Approximately 75% of hepatic blood flow is derived from the hepatic portal vein, while the remainder is from the hepatic arteries.[3]

Unlike most veins, the hepatic portal vein does not drain into the hepatic vein.

Clinical significance

Portal hypertension

Increased blood pressure in the portal vein, called portal hypertension, is a major complication of liver disease, most commonly cirrhosis.[5] Stigmata of portal hypertension include those of chronic liver disease: ascites, esophageal varices, spider nevi, caput medusae, and palmar erythema.[6]

Pylephlebitis

Pylephlebitis is infection of the hepatic portal vein, usually arising from an infectious intraabdominal process such as diverticulosis.[7][8]

History

References

  1. ^ a b c Henry Gray (1901). Anatomy, Descriptive and Surgical (16 ed.). Philadelphia: Lea Brothers. p. 619. 
  2. ^ Harold M Chung; Chung, Kyung Won (2008). Gross anatomy. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 208.  
  3. ^ a b c d Plinio Rossi; L. Broglia (2000). Portal Hypertension: Diagnostic Imaging and Imaging-Guided Therapy. Berlin: Springer. p. 51.  
  4. ^ Benjamin L. Shneider; Sherman, Philip M. (2008). Pediatric Gastrointestinal Disease. Connecticut: PMPH-USA. p. 751.  
  5. ^ Dooley, James; Sherlock, Sheila (2002). Diseases of the liver and biliary system. Oxford: Blackwell Science.  
  6. ^ Key Topics in General Surgery (2 ed.). Informa Healthcare. 2002.  
  7. ^ Plemmons RM, Dooley DP, Longfield RN (November 1995). "Septic thrombophlebitis of the portal vein (pylephlebitis): diagnosis and management in the modern era". Clin. Infect. Dis. 21 (5): 1114–20.  
  8. ^ Perez-Cruet MJ, Grable E, Drapkin MS, Jablons DM, Cano G (May 1993). "Pylephlebitis associated with diverticulitis". South. Med. J. 86 (5): 578–80.  

Additional images

External links

  • Anatomy photo:38:12-0109 at the SUNY Downstate Medical Center - "Stomach, Spleen and Liver: The Visceral Surface of the Liver"
  • Anatomy image:7959 at the SUNY Downstate Medical Center
  • Anatomy image:8565 at the SUNY Downstate Medical Center
  • Anatomy image:8697 at the SUNY Downstate Medical Center
  • Cross section image: pembody/body8a - Plastination Laboratory at the Medical University of Vienna
  • figures/chapter_30/30-2.HTM — Basic Human Anatomy at Dartmouth Medical School
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