Monday, November 26, 2007

Appendix Isn’t Totally Useless

For quite some time now scientists have believed that the appendix has no apparent function since it cannot be removed without causing any noticeable effects to the person who has had it removed.

The appendix is a small finger-like projection connected to the cecum. On average the appendix is about 10 cm in length, but can vary from 2 cm-20 cm. It is found in the lower right quadrant of the abdomen, and is corresponds with a point on the surface know as McBurney’s Point. Before now the appendix has been said to be just a vestigial structure, meaning that it has no known purpose.

Recent studies at Duke University Medical Center that there are beneficial bacteria in the appendix that can aid digestion can ride out a bout of diarrhoea that completely evacuates the intestines and afterwards repopulate the gut. The appendix makes a good home for bacteria because they can remain their undisturbed until they are need.

There are immune cells found in the appendix and with this new research has lead researchers to believe that the immune system cells in the appendix are there not to destroy but to protect these potentially important bacteria from harm.

There is a biofilm that is found on the inside of the bowels consists of microbes, mucous and immune system molecules that are able to live together on the lining of the intestine. The Immune molecules are there to protect and nourish the “good” bacteria that are living in these colonies. More importantly these biofilms are the most pronounced in the appendix and become less prevalent as you move away from it. By allowing the "good" bacteria to grow we are preventing "bad" bacteria from growing in their place, thus protecting us from potentially harmful diseases and illnesses.

The function of the appendix might be more visible if it wasn’t for modern health care and sanitation. In diseases that cause severe diarrhoea this can be very beneficial. Due to the position of the appendix it is very difficult for anything to enter it, so when the entire contents of the bowels are removed, including the biofilm, the bacteria are safe from harm. They are now able to emerge from the appendix and repopulate the get before any “bad” bacteria has a chance to take over. However with the advances in modern health care and sanitation practices these “good” bacteria may have very little effect on our health, but in countries where diseases like these are a serious problem because their medical system isn’t a good as ours, this bacteria may be very important.

One possible for the reason of the high occurrence of appendicitis in industrialized societies may be because of what scientists call the “hygiene hypothesis” which states that “people in "hygienic" societies have higher rates of allergy and perhaps autoimmune disease because they -- and hence their immune systems -- have not been as challenged during everyday life by the host of parasites or other disease-causing organisms commonly found in the environment. So when these immune systems are challenged, they can over-react.” This over-reactivity of the immune system could lead to the inflammation of the appendix that has been associated with appendicitis. This could lead to the obstruction of the intestines that causes acute appendicitis, in which case the appendix needs to be removed.

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1 comment:

Dominic B. said...

I heard about this on the very popular CBC show Quiks and Quarks sometime in October. To unserstand this a bit more I think one has to dig a bit further. This interview with Dr. William Parker is, to my own taste, a bit weak and does not really explore and cover what it should cover. I like Bob MacDonald as a science journalist but it seems to me that this interview was not as good as the other he usually does. Hear for yourselves by downloading this MP3 file: