The appendix is a funny body part (so are our sphincters, by the way, but that’s a topic for a different article). Most people go their whole life without ever noticing its function. Then there are those lucky ones who are sent to the hospital for an emergency appendectomy when the little sucker becomes so inflamed, it could rupture. Who knew such a small organ could do so much damage? Did you know the appendix is no longer than 2-4 inches long? It’s tiny. It’s actually a very small pouch attached to your colon right at the juncture of the small and large intestines.

For years, many people thought (and many still think) that the appendix is a perfect example of a vestigial organ — an organ in our bodies that humans needed to function thousands of years ago but that is no longer needed now.

In 2007, that assumption was turned on its head by researchers at Duke University. They posited that the appendix is actually a “safe house” for good bacteria in case bad things happen to the digestive system. For many years before this research was published, the lead scientists in the study had been looking at the gut and established the presence of what is called a biofilm — a thin, mucusy layer that contains protective bacteria. During a tumultuous bout with a disease that causes diarrhea, the biofim in the intestines (along with everything else) is flushed out, but the good bacteria in the appendix remain safe. Once the intestines have been cleard of their contents, the good bacteria repopulate the gut before more harmful bacteria can move in.

Thank goodness for sanitation

In modern societies, where sanitation is paramount, it’s possible that the good bacteria hiding in the appendix never sees the light of day (or light of gut, I should say) and therefore the appendix could be seen as seemingly useless. It is perhaps only called upon to perform this lifesaving function in the absence of modern health and sanitation practices.

In 2011, this theory was given ever more credence when researchers at Winthrop University Hospital in Mineola, N.Y., concluded that the appendix was serving a useful function in patients infected with the bacterium Clostridium difficile. In patients with an appendix, the recurrence of the bacteria was only 11 percent, but in patients who had had their appendix removed, the recurrence of the bacteria was a whopping 48 percent — thus leading them to conclude that the appendix may indeed serve an important function: harboring good bacteria for when the body’s digestive system needs it most.

All of this is based on what has long been known of the appendix — that it is home to immune system tissue called lymphoid tissue. Lymphoid tissue’s function in the digestive system is to protect the gut against pathogens. Other parts of the digestive tract that have lymphoid tissue are the tonsils, esophagus, adenoids and the stomach. Up until these studies, though, it was never clear what purpose the lymphoid tissue served in the appendix.

So is the appendix just an appendix or is it part of the story itself? Some would argue that without the appendix in the back of a textbook, it would be hard to navigate. So it is for our bodies, friends.

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Why do we have an appendix?
Is it just a vestige of a mysterious organ, or does it actually serve a purpose today?