Even this is a very broad description. You could deal with offenders' primary care and overseeing medication (i.e. dealing with substance abuse) in a prison, but also work in the psychology department, where having a mental health or learning disability background will obviously be more useful, and do a completely different job.
However people i have spoke to that have worked in prisons teaching have said to be prepared for a challenging environment!
Im hoping i can find more on my travels over the internet ...
I'm not exactly sure which area I would like to work yet, I'm only in my first year of my degree so I've got a while to decide yet