Why, when we hurt our finger, do we put it in our mouth?

Posted on Jan 12, 2021      137

When we pinch it, cut it, hit it with a hammer, etc., we instinctively pull our finger to our mouth: we put it there, or at least start blowing on it. So why do we do this?

To answer this simple question, science has had to go quite a long way in studying the human nervous system. Back in the 17th century, scientists speculated that there were receptors throughout the human body that signaled the brain about tissue deformation. These signals are interpreted by the brain as pain. It took a long time before neurons, the principles of the nervous system, and the transmission of nerve impulses were discovered.

One of the most interesting stimuli for scientists, strongly influencing the emotional state of a person, is the sensation of pain. Therefore, it is not surprising that the methods of transmission of pain sensations have received a great deal of attention in science. In 1965, two researchers Patrick Wall and Ronald Melzack developed a theory they called the “Gate control theory of pain”. It tells us that there are several types of axons (branches of nerve cells through which impulses are transmitted), some of which open so-called “gates” through which pain signals are transmitted to nerve cells, while others close these “gates. Our pain sensations are determined by the efficiency of these neurites. The theory states that the axons blocking the influx of pain signals can be activated by a physical action: vibration of a certain frequency, massage or temperature.

What do we do when, for example, we hit our knees painfully against something hard? We immediately start rubbing it instinctively: of course, this will not benefit the irritated tissue after the strike, but it activates those axons that reduce the transmission of nerve impulses that are transformed into painful sensations. The same is true of the injured finger - squeezing it with your lips or the flow of air affects the nerve endings, which reduce the pain sensation. Over tens of thousands of years of evolution, we have learned to do this instinctively, without thinking about the reasons, but it is only recently that man could understand the essence of his actions.