Leftovers...

Three years ago, my appendix burst. The pain started in early evening; an intense throbbing around my umbilicus. I assumed it was payback for the gargantuan Caesar salad I had scarfed a few hours earlier, so I threw back an Alka-Seltzer and went to bed.

But the pain intensified and spread throughout my belly, eventually forcing me to kneel before the porcelain and surrender the salad. I spent the night writhing in bed.

By morning, the pain had migrated south, spreading along the base of my abdomen. I assumed it was a virus, slowly working its way through my GI tract. I walked around clutching my belly for two days before finally giving in and driving myself to the ER. (I blame my former profession for the procrastination. In the arena of firefighting, there is no worse stigma than being deemed a candy-ass.)

After a quick scan, they diagnosed the problem, whisked me off to surgery, removed the offending organ, and I was on the slow path to recovery. The doc said I was lucky to survive. By the time they cut me open, the appendix was a shredded mess, my belly a mass of infection. Complications would send me back to the hospital a week later, but I eventually recovered and the scar is barely noticeable.

My case is hardly unique. According to the University of Maryland Medical Center, over 70,000 appendectomies are performed each year in the U.S. And even with modern medicine, thousands still die, primarily from lack of proper diagnosis and prompt treatment.

But why is this? Why do we tote around an organ than has such potential to kill? And what the hell does this small appendage do, anyway?

For decades, we’ve heard the appendix is most likely a ‘vestigial’ organ - an evolutionary leftover. A body part that once functioned but, for some reason or another, has been dragged along the evolutionary path despite the fact that it no longer serves a purpose.

We are not the only species that possess such relics. There are cave-dwelling fish that still retain their eyes, despite being completely blind and spending their entire lives in the dark. Remnants of leg bones can be found buried deep in the hind musculature of pythons and boas, And even some whales retain vestigial legs; a throwback to when they once walked on land.

We humans are no different. In fact, the appendix is not the only vestigial organ we possess. Evidence of our evolutionary journey can be found on our skin, in our mouths, and even on our skeleton.

Let's start with the skin. When the hairs on your body stand on end – what we commonly call ‘goosebumps’ – you're exhibiting a carryover reaction from when our bodies were once covered with dense hair. By making the hair follicles erect, animals appear larger and more threatening. Think of a hissing cat in a defensive posture. And although we now lack the fur, the reaction persists.

Next come the teeth. Our dental arcade is reminiscent of the larger jaws of our ancestors. But over the course of evolution, our mouths have gotten smaller. Check out the jaws of the robust australopithecines; they were virtual nut crackers.  Ours, not so much. Our smaller jaws can no longer accommodate a full arcade, which explains why dentists make such cushy livings extracting wisdom teeth.

Our skeletons retain evidence of our primate kin. What were once our tails have been reduced to a few small bones that taper from the end of our spines. The coccyx is but a mere nubbin of its former self.

Even some of our responses are programmed from an earlier era. For instance:

You’re walking down a dark alley when suddenly, a man steps from an alcove wielding a knife. Your body automatically responds. Heart rate jumps, respirations increase, and the pupils dilate as a hearty dose of adrenalin is dumped into your bloodstream. Worst case scenario, you wet yourself.

All of this is part of the ‘fight or flight’ response, which is initiated by the amygdala – that region of your brain responsible for kicking your ass in gear when you’re faced with a perceived threat. This reaction and all its associated reflexes harken back to a time when we confronted physical danger on a regular basis. That same australopithecine was lucky to make it to adulthood without becoming a tasty morsel for a hungry leopard.

But back to the appendix… It turns out that little blob still has a purpose, even in our modern bodies. We now know it plays an important role in embryological development, producing compounds that maintain homeostasis within the developing fetus. In adults, it assists in the maturation of lymphocytes (white blood cells important for fighting infection) and even helps direct these cells to areas of the body in need of protection.  

So perhaps it’s not so vestigial after all. Who knows… maybe we’ll discover one day that our coccyx has some magical power. Stay tuned!

Here's a cool little video on the evolution of 'fight or flight' (although I take offense at the pterodactyl flying in the sky just before the caveman appears. Shame on University of Texas!)