For the cadavers we get, we're told that it's a privacy thing for why we can't know where ours come from. It's obviously owner privacy cause if it's a St. Bernard that died at X clinic, you could probably figure out who the owners were if you know who to talk to.
Because of my degree, I had to take human A+P and it's not bad once you get used to it. We didn't get to do the dissections (reserved for upper classmen), but we had four cadavers and there were about 5 of us per cadaver in the class. I was fine until the day they uncovered the face. Doing fine, got through lab. But on the walk back to my dorm, I went pasty white and had to run back to my suitemates' room and sit on one of their beds holding a trash can up to my face. I didn't get sick, but it was a weird experience. After that, no problems. I rationalized it that the person wanted us to do this with their body. I actually really liked the class.