29 August 2011

5 body flaws

The human body is both extremely complex and remarkably efficient. Yet, wonderful as it is, it certainly isn’t perfect. We take a look at five design flaws.


The human body is both extremely complex and remarkably efficient. Yet, wonderful as it is, it certainly isn’t perfect. In this article we look at five design flaws.

Many of the body’s design flaws spring from the fact that the human body is the product of a long process of evolution. Whereas evolution produces efficiency, it certainly doesn’t produce perfection. The key is that rather than designing from scratch, evolution can only re-arrange and build on what is already present.

1. The wisdom in wisdom teeth
Anyone who has had trouble with their wisdom teeth would know that these third molars bring nothing but pain. The reason for this is quite simply that we do not have enough room in our mouths.

Our distant ancestors, with their slightly longer jawbones, may have had room for them. But in the mouth of the modern human, wisdom teeth often end up having nowhere to grow to and become stuck (compacted) and have to be removed.

Wisdom teeth may have helped our distant ancestors chew all that harsh unprocessed foods, but today, they are little more than an example of outdated design that most people can do without.

2. The appendix
Even though it has been extensively researched, scientists have not managed to identify any clear function for the human appendix. But whereas we do not know what it is good for, we certainly know how life-threateningly harmful it can be.

Between five and ten percent of people will develop acute appendicitis in their lifetimes. When this happens, the appendix fills with pus and has to be surgically removed.

Interestingly, other mammals seem to have a similar structure to the human appendix, which they use for certain kinds of digestion. This strongly suggests that, like our wisdom teeth, our appendixes are inherited from our distant ancestors.

In addition, recent studies have suggested that removing the appendix may reduce the chances of developing ulcerative colitis. Add the fact that no adverse effects have been noticed from removing the human appendix, and the case for a design flaw is very strong.

3. Looking the wrong way?
We know that our eyes are certainly not the best in the animal kingdom. But whereas a suboptimal design seems to serve our purposes well enough, the human eye, as those of other vertebrates, nevertheless seems to be rather strangely laid out.

Our eyes are essentially wired backwards with the light-sensitive cones and rods (the eye’s 'film') situated behind a webbing of blood vessels and nerve fibres and facing away from the light.

One consequence of this design is that the nerves have to travel through the eye, which is why the human eye has a blind spot at its centre. By contrast, an animal like the squid has its eyes wired the correct, or more obvious, way around with the photoreceptors pointing toward the light.

In addition, the connection between the optic nerve and the retina is surprisingly fragile – something which makes the retina prone to detaching as we age.

4. Down the wrong pipe
Another aspect of the human body that is widely considered to be an example of questionable design is the way in which air and food briefly share the same pipe. In essence, this is why we can choke on our food.

A number of scientists have suggested that it may have been a better design to keep the trachea (air pipe) and oesophagus (the pipe food travels down) completely separate. Instead, these two cross, which is why food can go “down the wrong pipe” - something that can be fatal.

A small valve, or flap, called the epiglottis, helps close the trachea when swallowing food. While this does solve the problem most of the time, it certainly isn’t a perfect solution.

Furthermore, in children, the epiglottis can become infected, which can lead to severe inflammation. Though this can be easily treated, it can be very dangerous when treatment is not available.

5. Haemorrhoids
Haemorrhoids refers to a condition where veins in and around the anus become inflamed. They can at times be itchy and painful, and are usually first suspected when blood is noticed in the stool.

Possible causes include a genetic predisposition, the increased pressure in the rectum during pregnancy and straining during bowel movements. By the age of 50, an estimated 50% of adults would have experienced haemorrhoids.

There are strong suggestions that squatting during bowel movements may have a protective effect, something which suggests that modern toilets are at least part of the problem.

Either way, exposing veins to the kind of pressures and friction present in the rectum is certainly not good design.

Not adapted for longer life
Just as haemorrhoids suggest that our bodies have not adapted to modern toilets, a number of other body flaws also involve our inability to adapt to our changing circumstances.

One of the major changes of the last few hundred years, is that human beings are getting much older. This means we are more aware of how our eyes, ears, backs, hips and brains fail to stand up to the passing of time.

But, the mere fact that we are living longer suggests that we are doing a good job of adapting to the weak spots in our design. Whether it is using vaccines to train our bodies to spot infections, or wearing glasses to see better, we are certainly making progress.

But inguinal hernias, cancer, labour pain, autoimmune diseases (where the body attacks itself) are all still with us. All of which suggests that in terms of plugging the gaps in the design of the human body, we have a long way to go. – (Marcus Low, Health24)

Reviewed by Prof Don du Toit, head of anatomy at Stellenbosch University

Olshansky, SJ. If humans were built to last. Scientific American. March 2001.
Theobald, D. The vestigiality of the human vermiform appendix. December 2006.

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