What's the difference between an appendix and a cecum, and what are their functions?
The cecum is a visceral landmark that delineates the change from the small intestine to the large intestine. It's essentially a road sign letting you know where you're at, and is not a organ of itself.
The appendix is a small, previously thought "superfluous" fleshy worm-shaped organ at the junction between the small and large intestines. Recent research posits that the appendix is sort of a harbor for a person's gut flora that can re-populate the intestines should the existing bacteria die or get removed (diarrhea being the most common cause). It can also become infected, inflamed, and require surgery to remove (Appendicitis).