Arithmetic Logic Unit: Performs calculations with data from registers. Typically can be set to add, subtract, multiply and compare data.
Control Unit: Instruction decoder and register. Extracts instructions from memory and sends them to the registers and ALU for execution.
Registers: Flip flops that latch the data from the ALU or data bus.
Address bus: Sends an address to memory.
Data bus: Sends data to memory and receives data from memory.
Read and Write lines: Tell whether to load data from a particular memory location or write data to that memory location.