| 概要 |
We used scanning electron microscopy to observe the development of the ductus venosus in the fetal rat liver. At day 13 of gestation, the vascular system in the liver was already formed and the umbili...cal vein had branched many capillaries to the parenchyma of the liver and was connected to the posterior vena cava directly by one small ductus venosus. At day 14 of gestation, the umbilical vein bulged at its terminal part and bifurcated into the ductus venosus, which joined the posterior vena cava, and a branch that anastomosed with the vitelline vein. The ductus venosus had no branches and subsequently enlarged and then degenerated just before birth. The bulging part of the umbilical vein and its branches degenerated in the later stages of gestation. The vitelline vein developed to form the capillaries of the liver and the intestinal venous system. In the SD rat liver, the ductus venosus was therefore established by development of the terminal part of the umbilical vein, which anastomosed directly with the posterior vena cava.
ラットの肝臓内静脈管の発生分化を走査型電子顕微鏡で観察を行った.胎齢13日では肝臓内毛細血管はすでに形成されており,月齊静脈は肝臓実質内に毛細血管を分枝し,細い静脈管を介して後大静脈に合流していた.胎齢14日では,膀静脈終末部は膨大し,この膨大部は二分岐し,1本は後大静脈に連絡する静脈管で,他の枝は卵黄嚢静脈に連絡する吻合枝であった.静脈管は胎齢20日頃までは成長し,分娩直前になると退化を始めていた,また,静脈管から分枝する毛細血管は認められなかった.膀静脈終末部の膨大部は胎齢後期になると退化していた.卵黄嚢静脈は腸管の静脈を形成し,肝臓内では多くの毛細血管に分枝していた.ラットの肝臓では,後大静脈に直接吻合する1本の膀静脈終末部から静脈管が分化すると考えられる.続きを見る
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Mendeley出力
fam95_1_p009