I took physiology first and it worked well for me. I think the best option is taking them at the same time because of the amount of material that overlaps but that would be a lot of work. I found having taken physiology made anatomy easier. In physiology, knowing basic anatomy will be fine when learning mechanisms and such. All the detail you go over in anatomy is overkill when it comes to what you actually need in physiology.
I say take Physiology first.