Hello Physics Forum. Long time lurker, I've decided to make an account for myself to participated in such an awesome community. Now, my question is, why do humans vomit when the appendix gets infected? Does the bacteria that invades the deteriorating gut wall really travel far up the intestines and through the pyloric sphincter? Also, how come food doesn't easily get stuck in appendix opening (since the way it's shape looks like anything could get lodged in there)?