Apr 28 2014
As my last blog post, I wanted to blog about something that was actually really interesting to me. I came across an article that I found interesting because it was about organs that the human body no longer needs. It was just interesting to me, personally, because I thought everything in our body was needed and important.
Apparently, there are organs in our body that are basically useless. These organs are called vestigial organs, which are parts of the body that once had a function but are now more-or-less useless. An example of a vestigial organ is the vomeronasal organ (VNO), which resides in the nasal lining or roof of the mouth and can detect pheromones. In mammals, there is something that closely resembles a VNO in their nose. It is considered irrelevant because according to the article, if one were to study the anatomy of the VNO there are no cells that look like the sensory cells in other mammalian VNO’s. There are no nerve fibers connecting this particular organ to the brain. The molecules that bind incoming chemical signals are pseudogenes, which basically makes them inactive. Therefore, the human VNO is non-functional.
Goose bumps are another example of being vestigial. Goose bumps occur when muscles at the base of hair follicles in the arms and legs contract and pull the hairs upright. This is supposed to create a thin layer of insulating warm air. The reason for goose bumps to be considered vestigial is because since the human hairs are so small and tiny, it doesn’t function well enough to create a layer of warmth. Another example of a body part being vestigial is the tail bone in humans. It is known what a tail is supposed to function as for animals such as cats and dogs, but in humans it has taken another form of function. Its purpose in humans is to to be an anchor point for the muscles that hold the anus in place.
Lastly, another example of vestigial organs are wisdom teeth. Because humans body sizes changed rapidly, our jaws became too small to keep all our teeth, which causes overcrowding in the mouth. Over time, humans’ diets have also changed to being softer and more processed, meaning there is less wear in the back molars. With less wear in the back molars, there means for less space for the last teeth to erupt, the wisdom teeth. Since wisdom teeth are not being needed anymore, impacted wisdom teeth are being extracted regularly. As a result of this, there may be an evolutionary trajectory to losing wisdom teeth altogether.
In conclusion, I found this article to be really intriguing because my whole life I thought every organ and part of the body was a necessity. It is crazy to think that our body creates things that can be useless even though our DNA is told to make these various organs and body parts. This article just goes to show that there are so many interesting things about the body that we are still learning.