Hi i got my oil dipstic popping up, which tells me my PCV valve is broken

ok i ve read bout replacing it..which ofcourse sounds bad for me

but what broken PCV valve can lead to and what does it actually do and how it works?
also the rubber tube going to it cracked terribly...can this one cause oil dipstic popping up? or i would have oil all around the crack? (which i dont have)

any links? or maybe someone can be kind enough to tell me bout it?

cheeeeers