Phys would not be one of those classes to opt to take online...
Human Physiology courses also count towards the prereq, and I can't imagine a school not offering that. I'm studying for specialty boards right now and we use Guyton.
I agree with Shortnsweet. I really would not suggest taking that class online if you can help it. I am pretty sure vet schools accept human anatomy and physiology. I took 2 semesters of that and I had no problem applying to any of my schools. Does your school offer that?