Hepatic portal vein
The hepatic portal vein (often portal vein for short) is a portal vein in the human body that drains blood from the digestive system and its associated glands. It is one of the main components of the hepatic portal venous system.
Structure
It is formed by the union of the
and divides into a right and a left branch before entering the liver.
Note that the portal vein drains blood into the liver, not from the liver. The blood entering the liver from the portal vein, after being cleaned by the liver, flows into the inferior vena cava via the hepatic veins. The inferior mesenteric vein usually does not directly connect to the hepatic portal vein; it drains into the splenic vein.
Portal vein branches into many generation of vessels that open into hepatic sinusoids. Blood is recollected into the hepatic vein and enters the inferior vena cava.
Tributaries
The tributaries of the hepatic portal vein include:
Physiology
Almost all of the blood coming from the digestive system drains into a special venous circulation called the portal circulation. This is because it contains all the nutrients and toxins that have been absorbed along the digestive tract from ingested food. Before these absorbed substances can go into the systemic circulation (the main blood circulation in the body), it must be filtered first to remove or "detoxify" toxic substances first. This filtering and detoxification is one of the functions of the liver.
Role in disease
Increased blood pressure in the portal vein, portal hypertension, occurs in liver disease (mainly cirrhosis), and may lead to various complications (ascites, esophageal varices, spontaneous bacterial peritonitis). A disruption of the hypothalamo-pituitary portal veins is referred to as Pickardt syndrome (suprasellar failure).
Portacaval anastomosis
The portal venous system has several anastomoses (portacaval anastomosis) with the systemic venous system. These are of consequence because in cases of portal hypertension these anastamoses may become engorged, dilated, or varicosed and subsequently rupture.
See also
- Portal vein
- Portal venous system
Additional images
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|
Veins of the torso |
| Coronary |
coronary sinus (great cardiac, left marginal, small cardiac, middle cardiac, posterior of the left ventricle, oblique of the left atrium) • anterior cardiac (right marginal) • pulmonary |
Thorax/
SVC |
brachiocephalic: inferior thyroid - thymic - internal thoracic (anterior intercostal, superior epigastric) - left superior intercostal - supreme - vertebral - internal jugular - subclavian (axillary: lateral thoracic, thoracoepigastric) - pericardiacophrenic
azygos: right superior intercostal - bronchial - intercostal/posterior intercostal 5-11 - accessory hemiazygos/hemiazygos - superior phrenic |
| Vertebral column |
vertebral venous plexuses (external, internal) • spinal (posterior, anterior) • basivertebral • intervertebral |
Abdomen/
IVC |
to IVC (some to renal vein on left): inferior phrenic - hepatic - suprarenal - renal - gonadal (ovarian ♀/testicular ♂, pampiniform plexus ♂) - lumbar - common iliac
to azygos system: ascending lumbar (subcostal) |
| Pelvis/common iliac |
median sacral vein
external iliac: inferior epigastric - deep circumflex iliac vein
internal iliac - posterior: iliolumbar - superior gluteal - lateral sacral
internal iliac - anterior: inferior gluteal - obturator - uterine ♀ (uterine plexus ♀) - vesical (vesical plexus, prostatic plexus ♂, deep of penis ♂/clitoris ♀, posterior scrotal ♂/labial ♀) - vaginal plexus/vein ♀ - middle rectal - internal pudendal (inferior rectal, bulb of penis ♂/vestibule ♀) - rectal plexus |
Portal system/
portal vein |
splenic: short gastric - left gastroepiploic - pancreatic - inferior mesenteric (superior rectal, left colic)
superior mesenteric: right gastroepiploic - pancreaticoduodenal - jejunal - ileal - middle colic - right colic - ileocolic (appendicular)
direct (cystic, left gastric/esophageal, right gastric, paraumbilical) |
| fetal |
ductus venosus • umbilical |
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