What is the role of a motherboard in terms of how components communicate with the processor (via the system busses).

Therefore, for each component, which communication bus is involved and what is the route that data takes from the component to the processor, including; 

* The bus name
* Whether bus is serial or parallel
* The name of any bridges involved
* Also, what is the the role of
a bridge

The components are:

* **Internal components**:
Floppy Drive, Hard Drive, CD/DVD
Drive, Memory, Processor Power
supply, Graphics card & Sound card
* **External devices**: Monitor, Keyboard, Mouse (PS2 & USB),
Printer, Pen Drive

I have absolutely no idea of what the routes are and how motherboards communicate, could someone give me a start here? Thanks.