OP: Since I just went through the year of physiology you're about to sink yourself into, I would not recommend buying Boron. I did, and it's sitting on my shelf, looking sleek, sexy, and unopened.
I used Costanzo, because our friends state-side seem to prefer it. It's not a bad read, but my favorite books to read for all the physiology stuff were as follows:
1. Heart = Lilly's book on Cardiac Pathophysiology or whatever
2. Lung = Pulmonary Physiology (Lange) and Pulmonary Pathophysiology (Lange) The latter is dense, and difficult to read, but if you really try at it, it's a valuable text. I didn't have the time to use it very well though.
3. Kidney = Vander's Renal Physiology (Lange) - this book is absolutely FANTASTIC. If you really want to nail kidney physiology to the wall, and don't want to rely on UBC's wonderfully watered down teaching, this is a great great resource. Highly recommended.
4. HDI = not exactly physiology, but buy Levinson's Lange book on Microbiology (can't recall exact title). It's fantastic, complete, lots of questions at the back etc. A very very good resource for a block that they don't really bother teaching at UBC. But then again, infection isn't an important part of medicine at all...right?
*If you read the above books, and know the material inside and out, you don't have to attend a single lecture, and you'll be miles ahead of classmates trying to slog their way through horribly disorganized and pathetic teaching materials*
5. PRIN - Internet. I never read a chapter out of any textbook. If some of the lecture notes don't make sense (and there are plenty that won't), then you do some reading. Costanzo might be of particular use here in regards to the muscle physiology that you'll be covering; especially the smooth muscle pharmacomechanical coupling which is explained wonderfully horribly.
If you want any more gory details, PM me. Anyone who likes Calvin and Hobbes enough to avatar it is a friend of mine 🙂