The appendix is a small pouch off the large intestine. The wall of the appendix contains lymphatic tissue that is part of the immune system of making antibodies. Removing the appendix doesn’t cause any harm because there are several other areas in the body that contain similar tissue-the spleen, lymph nodes, and tonsils. The spleen and the tonsils can also be removed.
From: Why do Men Have Nipples?
by: Mark Leyner and Billy Goldberg, M.D.