I studied red eared sliders in my biology course. It was interesting to say the least, but horrible as I had to dissect one. I found tumors on her pancreas, so her death saved her from a life full of pain and suffering.
I have a few diagrams which are a little more in depth than what jenaero posted, they may be helpful to some of you:
I also have pictures of the labeled parts on a real turtle. These pictures were from my book, and are for instructive purposes only. I will not post the pictures here as
they are graphic and I would not want to subject you all to that. I will provide the links to them, for those of you who may be interested in that sort of thing.
http://tinypic.com/r/w72a29/5http://tinypic.com/r/2vdr03a/5http://tinypic.com/r/f25575/5http://tinypic.com/r/xfaji8/5http://tinypic.com/r/2m2jkp1/5[admin edit = bolded warning]