Sometimes a study comes out and you have no option but to get excited because the topic is simply…


Okay, so maybe the appendix isn’t exactly what you might consider headline news. After all, it’s long been considered an evolutionary artifact with no real use in humans. Yet, in the city of Glendale, Arizona, a research team at Midwestern University have revealed this tiny organ may indeed serve a valuable purpose.

It may be a safe house for friendly bacteria…

skeptical(Yeah, I know it sounds sketchy…)

This theory has been around for about a decade but no one has ever been able to explain it in a credible manner. Thankfully, that’s what the researchers as Midwestern University set out to do in a very systematic and painstaking way.

They took genomic information from 533 different species, all of which had some indication of an appendix. Some of them were definitive while others were more sketchy in nature. Some of the more obvious ones (and one non-existent one in G) can be seen here…

(Can you guess which animals they are?)

With the species in place, the team then went about organizing them in a timeline of evolution in the hopes of finding some reason for this intestinal tag. They did this by comparing a variety of different gastrointestinal structures, such as the cecum area. Scores were made based on the shape, size, and function of each part of anatomy. Then environmental factors were thrown into the mix, such as latitude and longitude, population density, and diet.

By the time it was all said and done, I’m sure they were not in the mood for….

ribbit2(Singing and Dancing…)

But, the results paid off as they were able to develop several links between evolution and the appendix. Most were anatomical in nature but one significant link got me in the mood for some MALT!

malt2(Not that kind…)

The appendix is rich in two forms of immune tissue, gastrointestinal associated lymphatic tissue (GALT), and mucosal associated lymphatic tissue (MALT).

kermit2(Get it?)

Both these immune types are specifically designed to help us deal with whatever comes into the gastrointestinal tract. Having more GALT & MALT can also be good for our friendly bacteria. The cells in this area help to stimulate the growth of several beneficial species through a variety of chemical cross-talk mechanisms.

In essence, having that appendix might help ensure you have a healthy and diverse microbial population that is…

telus-frog(Sitting Pretty…)

Of course, all of these theories are still up for debate. Even this study suggests there are many questions to be answered before we can truly say the appendix is a microbial safe haven. Yet, this study adds to the theory that as we evolved through time, our bodies learned how microbes are for the most part our friends and wanted to be sure we loved them biologically.

Now if only we could love them emotionally like we do….

frog-kiss(You get the idea…)

For more on the paper, which sadly is not open-access but I felt definitely worth discussing, you can read more at ScienceDaily: Appendix may have important function, new research suggests.

Oh, and as for those intestinal drawings, here are the answers:
(A) Wombat (Vombatus ursinus);
(B) Brushtail possum (Trichosurus vulpecula);
(C) Rabbit (Oryctolagus cuniculus);
(D) North American beaver (Castor canadensis);
(E) Rock hyrax (Procavia habessinica);
(F) Orangutan (Pongo pygmaeus);
(G) Bush-tailed phascogale (Phascogale tapoatafa).