what the essential difference between akka and ThreadPool+BlockingQueue in ONE Process?

We know Akka is one implementation of actor pattern. Without Akka, I usually implement a simple actor pattern using ThreadPool+BlockingQueue. So the message is offered into the queue, and the works(actors) take the message from the Queue, then do what they should do. Of course, this kind of implementation can be only in just ONE process.

So as to in one process,

1. What's the essential difference between these two(Akka vs. ThreadPool+BlockingQueue)
2. Moreover, what's the difference between actor pattern and producer-consumer model?