hmm, i'm not sure i can help, but i'll try....
my experience with this has been that only some lecturers will cover how certain things function, and others have told us that this is info that we should already know and maybe just review it before we get to that subject - so in answer to your question, for my school it wasn't relearning, we built upon the knowledge we got from our pre req's. i am very thankful to my a&p instructors, as they gave me a solid base which of course you constantly use in nursing (keep your notes!)
i know that feeling of it "just not sinking in"....prior to nursing, i had trouble also, but over time, i discovered things that helped me remember things - have you tried index cards, taping the lectures or making recordings of your own voice with key points? i also relisten to the lectures and rewrite notes to catch anything i might have missed
best of luck to you,