All the components are given their power supply from Vdd and GND lines. You may observe in the pin configuration of chips that there are several Vdd and Gnd pins. This is done for the better power handling of the chip.
There are signals in the chip like the precharge signal, which when asserted, all the lines draw a lot of current. This can lead to a "Voltage droop" and a "Ground Bounce". This can harm the logical immunity of the chip as well as other circuits, if it is not decoupled properly. The multiple Vdd and Gnd pins help to reduce this harmful phenomenon.