Many acini form the parenchyma of the lobule. The acinus is the functional unit of the liver.  Obviously the liver cells close to the terminal portal vein receive a blood richer in oxygen and nutrients than those located near the central vein,therefore the cells in these different zones perform different biochemical functions.  Also they respond differently to injuries.  By convention we call the area around the central vein zone 1 (Z1), the area near the terminal portal vein zone 3 (Z3)and the area in between, zone 2 (Z2).

Figure 5 - Acini Forming Lobules