What the hell is the appendix and why do we have it?

The appendix is a blind ended tube connected to the cecum (a pouch-like structure of the colon) and is located near the point where the small intestine and large intestine meet (lower right corner of the abdomen). It is about 10 cm in length and 7 to 8 mm in diameter. No one knows exactly why we have an appendix, but some have suggested theories.

One possible explanation, proposed by Charles Darwin, is that it was once used for digesting leaves as primates. Over time, we have eaten fewer vegetables and more meat, so this organ became smaller to make more room for our stomach. Herbivorous animals, for example, have a very long cecum. It may be that the appendix is a vestigial organ used by our ancestors but is no longer needed by us.

A second notion contends that the appendix provides a safe haven for good bacteria until they're needed. So if your gut is affected by diarrhea or another illness, the good bacteria in the appendix can take over to keep you healthy. But in societies with modern medical care and good hygiene, the bacteria don't give any added benefit and thus renders the appendix useless. According to this hypothesis, the lack of germs in modern society may cause the immune system to overreact and attack the good bacteria stored in the appendix. Then the inflammation that comes with appendicitis may obstruct the intestines. So actually, the appendix does more harm than good in a society like ours.

Another theory is that it helps maintain homeostasis in fetuses around the 11th week of development.

At any rate, there have been no discernible negative side effects after the removal of the appendix.