The Function of Your Appendix


The appendix has so far been thought to be completely useless to humans. The only thing it seems to do well is get inflamed and threaten to burst, creating all sorts of havoc in your body. However, it appears that there actually is a reason for its occasionally inconvenient existence.

The appendix is an organ that makes up a part of your gastrointestinal (GI) tract. The GI tract is a group of complex organs, each designed to help your body absorb and digest food. Your appendix is located in the lower right part of your abdomen, and is a thin, roughly four inch long tube, attached to a part of your large intestine called the cecum. The cecum is a small pouch typically considered to be the beginning of the large intestine. Charles Darwin presumed that the appendix was a shrivelled up portion of the cecum. He came to this conclusion as the cecum is much larger in herbivores compared to modern humans. Thus, he assumed that our distant ancestors also had a large ceca which allowed them to dine on leaves like herbivores do today.

However, as these ancestors moved on to having more of a fruit based diet; the cecum shrank but was not completely eliminated, resulting in the appearance of the appendix. However, as we examined the appendix more closely, we found that it was made up of material that was quite different to the cecum and could therefore not be a part of it.

Thereafter, people assumed that it simply was an organ that had a purpose originally, but is no longer useful today, labelling it as a vestigial organ. However, the modern argument is that if this was the case, evolution should have eliminated this organ already. Thus, a study was conducted by researchers at Midwestern University, which examined the evolution of 553 mammal species over 11 million years.

It attempted to pinpoint where the appendix had emerged as a new trait as well as well as when it disappeared entirely. In order to support the common belief that the appendix was just a vestigial feature with no real benefit, the researchers would have to see a trend indicating that it only evolved a few times while disappearing quite regularly. However, the evidence pointed to another conclusion, as it had appeared to evolve between 32 and 38 times, disappearing only six times. This indicated that the appendix was in fact of use to certain mammals, concluding that it could not be defined as vestigial.

Therefore, many scientists believe that it does provide us with some function.

This was indicated through other studies which found that the appendix contains a type of tissue associated with the lymphatic system. The lymphatic system’s primary function is to carry white blood cells throughout the body in order to fight infections. Thus, recently scientists have been able to discover that this lymphatic tissue in the appendix encourages the growth of some beneficial gut bacteria.

This healthy gut bacteria usually plays an important role in human digestion and immunity. Thus, the ‘safe house’ theory was developed, illustrating how the appendix protects this bacteria in its long tube-like structure, only to emerge when certain diseases wipe out the gut bacteria that were already in the GI tract. Therefore, once the immune system has fought off the infection, the bacteria exits the appendix and re-colonises the GI tract.

This theory was further supported as people who have had their appendix removed are more likely to suffer from bacterial infections. However, most people still tend to live a long and healthy life after an appendectomy which points to both how the immune system probably picks up after its absence, and to perhaps the effectivity of modern medicine.

However, if you are still not convinced by the appendixes value and would rather take it out now than risk it bursting, know that it is also useful for reconstructive surgery. If the urinary bladder ever has to be removed, a section of the intestine is formed into a replacement bladder, with the appendix used to recreate the ‘sphincter muscle’ so that the patient remains continent or able to retain urine.

It can also be used as a replacement for a diseased ureter, which allows urine to flow from the kidneys to the bladder. Thus, even if it’s inherent uses are not much of an advantage in modern times; it can still be used if healthy as a backup of sorts. Therefore, although Darwin may have prematurely disregarded the appendix, this long dismissed organ is finally getting some deserved recognition for keeping us relatively healthier which can finally balance out it’s overwhelming negative press for giving almost one in 20 people appendectomies.