The vermiform appendix: not a useless organ.

The appendix has often been seen more as a nuisance rather than an important part of the human anatomy. Early misconceptions have led to the indiscriminate removal of the appendix from the body. Long thought to be an evolutionary remnant of little significance to normal physiology, the appendix has more recently been identified as an important component of mammalian mucosal immune function, particularly B-lymphocyte-mediated immune responses and extrathymically derived T-lymphocytes. This structure helps in the proper movement and removal of waste matter in the digestive system, contains lymphatic vessels that regulate pathogens, and lastly, might even produce early defences that prevent deadly diseases. The appendix is one of the guardians of the internal environment of the body from the hostile external environment.