Why do we have an appendix?


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The human evolution cannot be considered perfect. While it has managed to shape us into the most advanced species on the face of Earth, it has left a few “gaps”, on our body itself, which makes us think whether this evolution was fruitful at all.


Inspite of evolution, which has a tendency of eliminating parts of our body that we no longer require – such as a tail, as found in other primates – there are a few parts of the body which have resisted being eliminated. These parts of the body are called VESTIGIAL ORGANS.

The Oxford English Dictionary defines vestigial organs as “structures remaining or surviving in a degenerate, atrophied, or imperfect condition or form”. In layman terms, a vestigial organ is one that serves little to no function in the body now, but could have been of biological significance at an earlier stage of the human evolution.

Organs on the human body which exhibit vestigiality (i.e., the ability to exist as a vestigial organ) are appendix, wisdom teeth and tailbone (called the coccyx). The vestigial organ that has perplexed scientists since the invention of X-Ray imaging is that of the APPENDIX.

What is the appendix?

Appendix is a thin, four-inch tube, with a finger-like structure, placed at the junction of the small and large intestine. The removal of appendix, called appendectomy, is a well-known procedure; it is performed due to inflammation of the appendix, triggered by unknown causes.

human body

As mentioned before, the appendix is widely considered as a vestigial organ, especially because it’s function is not known yet. Scientists from all over the world have been hypothesizing about the essential role of the organ, but a consensus has not been formed.

The reason for the curiosity harboured within the scientific community with respect to the function of the appendix can be attributed to the fact that it is a part of the digestive tract – one of the vital organ systems of the body. Thus, it is assumed that the appendix must play a role in digestion, or any other accessory processes.


Proposed Functions of the Function of the Appendix

  1. Gut Microflora

One of the popular theories that surfaced was that of the appendix containing “good bacteria”. It is a well-known fact that the human body harbours millions of bacteria, especially in the digestive tract – these bacteria are called the gut microflora. These microbes help the digestive enzymes in breaking down of the ingested food into smaller substances for better absorption of biological material.


The theory surrounding the appendix suggested that it acts as a “fall-back” system for the gut microflora. After a severe digestive disease – such as diarrhea or dysentery – the gut microflora are highly diminished, thus extending the recovery process. Here is where the appendix steps in.

Since the appendix is a tube-like structure, it is often described as being like a sac or a pouch. Assuming it does harbour good bacteria, they’re enclosed in the sac and would perhaps be saved from the invasion of pathogens in the rest of the digestive track. In order to replenish the gut microflora, the appendix transfers the good bacteria in itself to the digestive system. So, the gut microflora can be repopulated.

This theory has been backed by the fact that people who have had appendectomy may take longer to recover from illness such as diarrhea than people who have an intact appendix. It is thus suggested by doctors that the appendix be removed only in case of appendicitis or an appendix tumour.

  1. Immune Response

A less known theory is that the appendix contains lymphoid cells, cells which play a crucial role in the immune system of our body. Lymphoid cells are mostly originated from the lymph organs, named the thymus and the bone marrow, but this theory is suggestive of the fact that the appendix possessed “extrathymically-derived lymphocytes” – referring to the fact that these cells have not originated from the lymph organs, but rather from some other source. However, this theory seems to be less credible than the one pertaining to the gut microflora.


Following this discussion, it can be concluded that the appendix can no longer be considered a vestigial organ – despite it’s little function. Since nearly everything present in and on our body has served a purpose to be advantageous to the individual, it can be assumed that the appendix is too. If scientists continue to work on the function of appendix via all the modern instruments, one can hope that it’s role in the body – be it in digestion or immune response – is confirmed soon.

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