I had no idea that there were so many sphincters in the body. I always thought there was just one, or, at the most, two with one being at the top of the throat and one being at the other end.
I guess the body just works without you needing to be aware of all the little things that it's doing. I actually heard a scientist on a show the other day say that there were basically enough neurons in the human digestive system to make up an entire cat brain. And that's pretty impressive.