Yawn
The causes of yawning are still not fully known. A common view is that a person starts to yawn in a poorly ventilated room with a deficiency of oxygen, has been refuted by scientists. Experiments have shown that people who were given more oxygen or carbon dioxide, yawning the same.
As shown by numerous studies, with the state of sleepiness, fatigue, boredom in the brain of the braking process begins to dominate the excitation process. As a result, slowed and some body functions, including breathing. It is rare, less deep, because of which accumulate in the blood carbonic acid and other products of metabolism. Influencing the respiratory centers of the brain, they provoke a yawn.
During deep slow breaths blood enriched with oxygen. A muscle strain in the mouth, face, neck, participating in the act of yawning, increases the velocity of blood flow in the vessels of the head. This improves blood flow to brain cells, and metabolic processes in them are more active. In addition, yawning, people are often stretched, straining muscles of hands, legs and especially the back. Signals from the strained muscles come into the reticular formation, one of the main functions of which is to maintain the tone of the cerebral cortex. These pulses activate the reticular formation, and she, in turn, stimulates the neurons of the cortex, as if forcing them to shake off the slowdown. Thus, yawning activates, though very briefly, the activity of the brain.
If you yawn the most tense jaw muscles, and they have a direct impact on vision. Yawn very useful to those who suffer bruxism, grinding his teeth in his sleep. During the day many times, from the soul, it is necessary to yawn, stretch, thus making a deep breath and noisy breathing out – it relieves muscle tension jaw.
When you fly in an airplane, from the pressure difference ears. And as the middle ear cavity Eustachian tube is connected to the pharynx, the yawning equalizes pressure.
Yawning – is not only a symptom of boredom or sleepiness, but also a complicated operation to regulate the temperature of the brain, say U.S. researchers. According to professor of psychology at the University of New York Andrew Gallup, the human brain like a computer: “overheating”, he begins to work worse and causes a yawn, which provides blood flow and colder air. The result is improved functioning of the brain. Scientists also argue that contrary to popular belief, yawning is not conducive to falling asleep, but rather, helps ward off sleep and invigorate the body.
Specialists from many years working with test pilots and parachutists, not once noticed that before senior departures, many of them began to yawn.
In situations with strong emotional
tension, danger, spontaneously activated ancient mechanism: man instinctively stops breathing. And then turn on another mechanism – yawn. At the same time a deep breath at oxygenating their blood, it enters the brain to the muscles, maintaining state of readiness to act.
We know that yawning is contagious: one is to begin to yawn, and all around pick up. The fact is that yawning is easily emerges as the imitative reflex. This reflex causes us not only to yawn, and smile if someone nearby laughing.
U.S. scientists also found that thin and prone to introspection, people are more prone to yawning.
Psychological tests have shown that people who are immune to yawn at the same time are more stringent in nature.