If you want to learn how the organ systems work, that's physiology. I liked Boron in med school, if you want a basic understanding just read the subtitles and figures.
The basic stuff doesn't change drastically with time, and you can get older versions of the books cheaply.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.