Where is the air intake on the mac?

I was just getting ready to move to a new place and while packing up, there was a lot of dust blown out from some of the older objects in my room. Of course, my mac was exposed and then i started thinking: my desktop PC gets super dusty, but i can clean that out easily. However, my macbook only has one air vent that i see blowing out however, i dont see where air is being taken in.

Anyone have any tips regarding caring for a mac that took in a lot of dust? where is the air intake on a macbook also?