Destruction of the introjected good parent

Hello,

I'm reading a text for my classes and I have a problem with one expression. Can you help me with this one, please?

The sentence reads: "You know,” Henry said, “We’ve been talking about this sort of thing in my psychology class. When people are criticized or rejected, they experience it as.... uh.... the destruction of the introjected good parent..... In fact, I just started writing a paper about it."

What is the introjected good parent?

The whole text is here: http://truecenterpublishing.com/tcp/defense_lunch.pdf

Thank you