When viewed under a microscope, the liver is seen as large network of units called hepatic lobules. The hepatic lobule is very small and looks like a six-sided cylinder. 

    the lobule itself is surrounded by connective tissue and has 5 to 7 clusters of vessels around its edges. These vessels include a branch of the portal vein, a branch of the hepatic artery, and a bile duct. 

    A central vein runs through the middle of the lobe and is surrounded by cords of liver cells that radiate out in all directions. Between these cords are wide thinwalled blood vessels called sinusoids. All of the blood drains into a hepatic vein which then circulates throughout the body. 
 
    在顯微鏡下，肝臟是由肝小葉為單位的網狀結構。肝小葉非常小，是六棱柱體。 

    小葉的周圍是結締組織，邊緣圍繞著5-7串脈管，有門靜脈、肝動脈和膽小管。 

    小葉的中央由中央靜脈穿過，周圍被向四周呈放射狀排列的肝細胞索包圍。在索之間是擴大了的毛細血管叫血竇。所有的血液都流入肝靜脈參與體循環。