Hey could someone explain what this is.

Was cleaning some parts today and wondered what this was. Couldnt find anything in the fantastic Haynes haha and iv tried searching the net but its hard when I'm not sure what I'm looking for. But anyway when I took it of it was clogged up on the part and on the intake manifold.
Intake manifold

Part

What does it do.
What would the clogged up holes be a result of and what implications would they have on the car.
Appreciate your help.