Sunday, February 19, 2012

The Most Dangerous of Worms

"The modern king has become a vermiform appendix - useless when quiet, when obtrusive in danger of removal"

Austin O'Malley

For this post's quote, I nearly went with "Usul, we have wormsign the likes of which even God has never seen!"
In a way, it's actually more apt.

Last month, I had the opportunity to perform my very first emergency appendicectomy after having observed and assisted only once (a couple of months ago at that), and right before scrubbing in, I spent a couple of minutes reading an online step-by-step guide on how to do it. Most of my superiors agree that a house officer should assist in at least three appendicectomies before going for it, but lucky for me, the medical officer who was supervising me did not ask if I've fulfilled that informal quota. Having Caesared a baby out of a mother's womb before, slaying a little worm really felt safe in comparison. Incidentally, the worm Ouroboros had bitten its tail and came full circle - when I was 5 years old, an appendix tried to take me out. Now after 5 years of med school, I served my cold, cold revenge and took one out.

However, this post is not about my mostly ad libbed journey through my medical training. It's about the vermiform appendix, which is basically Latin for "worm-like extra-bit".

The Gastrointestinal Tract Simplified
You'll notice that "worm-like extra-bit" is a very accurate description.

Appendicitis refers to the inflammation of the appendix, and it happens when its teeny-tiny opening into the caecum gets blocked by something. That something may be a bacterial or viral infection, parasitic worms, cancer, swallowed foreign objects, or a faecolith (which literally means "shit stone"). Depending on which part of the world you live, how old you are and which gender you belong to, there's about 6 to 16% chance that your appendix will try to kill you in this lifetime - and 27 out of 10,000 times, it will actually succeed, even in spite of the full force of modern medicine. Just owning one is a possible mortal hazard waiting to happen. So why oh why are we equipped with a self-destruct mechanism hanging uselessly off our large intestines?

If you believe that God created us in the form we now inhabit, then you must also believe that God is a blithering halfwit who can't even build an alimentary canal without accidentally installing a killswitch. However, if you understand evolutionary biology, you'd recognise the appendix as a vestigial organ serving none to non-essential functions as suggested by its high variability in shapes, sizes, orientations and positions and evidenced by homologous structures in other animals. The appendix is basically part of the caecum writ pathetic, and in herbivorous mammals, their caeca are capacious and contains cellulolytic bacteria which aides in digesting plant material. In animals less dependent on vegetation for food (such as us humans), most of our caecum is a shrunken worm-like structure. In fact, some carnivores have their entire caecum reduced to an appendix vermiformis. Further proof that the appendix is a vestige of our evolutionary heritage is that our ape cousins like orang utans have larger appendices while our most closely phylogenetically-related species, the chimpanzees, has an appendix very similar to ours. Rhesus macaques, which is considered lower primates compared to chimps and orangs (and is more distantly related to us than either), don't even own an appendix but instead, have a broad caecal end much like other herbivores. We are technically in the process of losing our caeca, and the appendix is what we get out of it.

Okay, those of you who paid attention in 2009 saw the internet exploded with scientific news of a possible function for the human appendix. To understand this, you must first understand that our guts are commonly filled with helpful, "good" bacteria which lives symbiotically with us, helping us digest food, teaching our immune system how to fight, and fending off so-called pathogenic "bad" bacteria. When our gastrointestinal tract does get invaded successfully by non-native microorganisms and everything is being washed out in a diarrhoeal holocaust for example, the appendix functions as a kind of bomb shelter for the local friendly bacteria where they wait out the shitstorm, ready to recolonise our colons (heh) as soon as conditions are right for them again.

Some creationist cretins who denies evolution touted this particular bit of research as ahah! proof! that since the appendix has a function, it is therefore not a vestigial organ and that God is awesome while Darwin smells.

They neglected to note, however, that the paper in question actually supports evolution. It aimed to explain why the appendix, being the peril disproportionate to its perks to higher primates, is still being conserved in their bodies. It is an interesting bit of medical science, but one of its senior authors accidentally stuck some feet into his mouth and, much to the glee of creationists everywhere, said:

"Maybe it's time to correct the textbooks. Many biology texts today still refer to the appendix as a vestigial organ."

Wrong. A vestigial organ, by definition, doesn't mean that something is useless. Evolutionary vestiges refers to any diminished structures that played a larger physiological role in a species' ancestor than in present. Charles Darwin himself wrote of vestigiality in On the Origin of Species as much: "an organ, serving for two purposes, may become rudimentary or utterly aborted for one, even the more important purpose, and remain perfectly efficient for the other." In the case of the human appendix, it is the reduced part of the plant-digesting powerhouse of a caecum our evolutionary forerunners used to have in their employ i.e. vestigial. Maybe this narrow annex of the caecum have found new life as a reservoir for our gut flora in times of disease but so what? This happens all the time in evolution and we even have a term for it: exaptation. Feathers are the classical example of this process. It first evolved to keep theropod dinosaurs warm (yes, velociraptors were covered in feathers), and was then coopted for display and flight in their avian descendants.

And you know what? What minuscule function the vermiform appendix does perform for us doesn't seem to be all that important after all. Countless patients undergo appendicectomies every day around the world, all to no apparent ill-effects to their health. I mean look at me: 20 years without an appendix and still counting. You don't see me dying just because occasionally, water spouts out of my ass instead of crap after some bad sushi. But if I didn't have that appendicectomy 20 years ago, I very well could have.

So there you go: is God an omni-incompetent nincompoop or did evolution happened? You decide.

k0k s3n w4i


Liz said...

You should do illustrations for biology/medical text books! I'd read them....for the diagrams xD

Atlantisian said...

That's interesting. I never have great appreciation towards the vestigial (although they are parts of my flesh and organ). In fact they caused me nothing but trouble. I had a few "suspected" appendicitis incidents, and my dear wisdom tooth had given me nothing but headaches, migraine, sleepless night and kidney burnout (too much of pain killers). And i'm seriously considering surgical removal for the wisdom teeth. Maybe you can do some justice to them as well?

nicoletta said...

there, we were once meant to graze like sheep. what's the human body doing - making an evolutionary shift out of sheepdom and toward godlessness?

did an evolutionary course and remembered that a person dropped out of it pretty soon just because the lecturer said on the first day, you can't use evolution to explain the existence of God, and vice versa.

k0k s3n w4i said...

Liz: i'm too lazy to do that. just look at the picture in this post: i was too lazy to draw all the small intestinal loops in the middle.

Atlantisian: all my wisdom teeth erupted properly except my lower left one which was still lost somewhere beneath my gum. i wrote about the appendix this time because i just performed an appendicectomy - ask me again if my lost molar start giving me trouble ;) if you're interested in knowing more, there's some links i can direct you to.

nicoletta: poetic. don't think i heard that one before, haha. i think it's true that you can't explain god using evolution (because there's no evidence for god, much less evidence for his/her evolutionary heritage), but you can totally explain evolution using god - as catholics do worldwide. i believe that the church's position is that god guided the evolution of humanity. but then again, evolution doesn't need that extra layer of non-explanation. it reminds me of something napoleon once said to pierre-simon laplace: "they tell me you have written this large book on the system of the universe, and have never even mentioned its creator." laplace famously replied: "je n'avais pas besoin de cette hypothèse-là." in english, that was "i had no need of that hypothesis."