Hiccups
http://www.scientificamerican.com/article.cfm?id=this-old-body
http://www.scientificamerican.com/article.cfm?id=what-causes-hiccups
The information in this article summary is from the second half of the article "The Evolutionary Origins of Hiccups and Hernias" and the full response of William A. Whitelaw in "What Causes Hiccups?".
Hiccups vary from short annoyances to long-term, problematic conditions. Persistent or dramatic hiccups can be caused by various disorders. Some causes include expansion of the stomach and movement of stomach acid into the esophagus, disease or irritation in the thorax, irritation of the phrenic nerve, and neurological lesions. Any hiccup, whether from a severe, prolonged problem or a short annoyance, results from a spasm or sudden, strong, contraction of the muscles in the throat and chest. The "hic" sound comes when, after the contraction begins, one sharply inspires air as the epiglottis closes.
Since hiccups are rarely isolated events, but rather occur consistently for quite some time, there is believed to be a "central pattern generator" somewhere in the brain. This means that, like those for breathing, coughing, and walking, there is a neuronal circuit that generates hiccups. The CPG for hiccups is a conditional oscillator because while it sends a reoccurring signal to cause a hiccup, it sends this signal only under certain conditions.
Observations of hiccups in a variety of animals and in the fetus body suggest that the CPG for hiccups comes from a previous stage of evolution. One bodily activity in animals similar to the hiccup in the humans is the tadpoles' use of gill ventilation. The tadpole, with both lungs and gills, cannot suck air into its lungs. The tadpole uses the pressure pump action of the mouth to fill the lungs and to push water through the gills. When breathing air, the tadpole closes its nose, mouth, and passage to the gills in order to compress the mouth cavity and force air into the lungs. It breathes water by closing the glottis and forcing the water out the gills. When pushing water through gills, tadpoles must keep water from the lungs. Therefore, while the tadpole inspires, the glottis closes. This is essentially the same action happening in the human body during a hiccup.
Along with connecting humans to an amphibian history, hiccups demonstrate a connection to a history shared with fish. Major nerves used by humans in breathing are inherited from fish. The phrenic nerves travel from the base of the skull in humans, through the chest cavity, and through the diaphragm. Anything interrupting these nerves can inhibit breathing. If these nerves are irritated hiccups can result. The unfortunate design of humans' phrenic nerves comes from fish who have gills closer to the neck instead of a diaphragm a good distance below it. Humans' shared history with animals like tadpoles and fish seems to reveal once useful and necessary mechanisms that now cause unnecessary, annoying, and even problematic issues.
The discussions in the two articles I read are presented in a clear and extreme evolutionary perspective. The arguments and information in the articles have challenged me to think of an adequate response correctly defending my faith and belief in creationism. I believe God created each species of animal as unique from other species and humans as different from all other animals. Different living species, as this article discusses, have evident similarities in both structure and function. While this may seem to point to evolution, I believe this fact shows that the essentially same structure or action used to help one living thing can create problems for another. This structure or action did not evolve from one creature to another, but is rather used in a different way producing different effects. I believe the authors of these articles stress ways similar structures and actions in animals and humans cause problems for humans. However, they neglect to discuss potential problems similar elements could cause in the animals. The articles discuss the mechanisms and structures involved in hiccups which are logical and useful in amphibians and fish, while cumbersome in humans. I find myself wondering if there are structures or mechanisms afflicting an animal species while similar structures or mechanism cause no such harm in humans.
The idea that an element similarly found in two different beings could cause harm to one and help another seems to reflect a larger connotation involving various aspects of life. For example, just as the same mechanism that helps tadpoles breathe causes unwanted hiccups, the same mouth that speaks kind, uplifting words can tear someone down with unkind, harmful words. Our creator choose to use similar elements in different species of his creation. The mechanisms useful for the tadpole and the nerve logical for the fish are both seen in the humans with seemingly less use and logic. Our creator also choose to give each person the ability to use his or her mind, mouth, and tongue to speak both kind and harmful words. The same mouth used kindly can be seen at a different time used harmfully. While our hiccups are not a matter of free will and personal choices, they can be seen, like unkind words, as an unbeneficial use of a mechanism that can be beneficial in other circumstances.
1 Comments:
I had never heard that evolutionists think that hiccups come from gills in evolution. That was actually interesting to me. It bet it was frustrating for you to read an article so heavily based in evolutionary philosophy. It is interesting to me how there are so many things in the body that can't be explained yet lke hiccups and the appendix.
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