| Research Abstract |
The "hepatic hilum" represents the site where the portal vein, hepatic artery, bile duct, lymphatics, and nerves are collectively found on the concave surface, whereas the "hepatic counterhilum" is the site where hepatic veins open into the vena cava. The paraostial hepatic tissue is enriched in hepatic aterial branches and lymphatic vessels.
Structural components of hepatic hilum in pig fetus develop at different stages. The portal vein is consistently found with primitive bile ductular profiles. At crown-rump length 11.7cm, the hepatic artery invaded the hilum and portal tracts in close relationship with bile duct which now has developed into the typical biliary tract surrounded by connective tissue. Lymphatics were then recognized in close vicinity. Nerves were first seen at CRL 20cm.
The hepatic counterhilum is arterial predominant. Portal circulation is decreasing. Circular musculature of portal vein is thickened so that the contraction causes the lumen to reduce in caliber. Some po
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rtal venules are being obliterated due to mononuclear cellular infiltration, other have vanished from the tract. Hepatic artery departs from the tract as an isolated artery and supplies the hepatic vein's wall with oxygenated blood. The longitudinal muscles of the hepatic vein are highly developed which accounts for its increased intramural tension. Atrophied lobules are encountered numerously.
Under experimental pathologic conditions, rat with endothelin-1 perfusion portally was found with significantly increased portal pressure and shrunken liver. The resistance site in the portal system was identified to be the distal segment of the preterminal portal venule of 40-80 mum diameter. The terminal branch, which is poorly developed or equipped with smooth muscle, the inlet venule, and the sinusoid did not show sign of contraction. Near large portal tract were observed cavities that resulted from expansion of perisinusoidal spaces.
In chronic portal hypertension of mouse with Schisrosoma mekongi infection, the hepatomegaly is found with parasites residing in the portal vein at hepatic hilum. Ova of 30-40 mum are distributed along the peripheral braches of portal vein, being surrounded by lymphocytic infiltration intermingled with hepatocyte degeneration and granuloma formation (200-400 mum). The hilum is relatively less involved in the infiltration. Less
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