Yawning is very important business
Yawning helps keep the brain cool, and the sinuses play a role in that process by acting as bellows, according to Gary Hack, of the University of Maryland School of Dentistry, and Andrew Gallup, of Princeton University.
Yawning occurs not because you are tired, bored, or even need oxygen, they argue. Instead, they say, yawning helps to regulate the brain's temperature.
"The brain is exquisitely sensitive to temperature changes and therefore must be protected from overheating," the authors write. "Brains, like computers, operate best when they are cool."
The scientists propose that the walls of the human maxillary sinus (pictured in green above) flex during yawning like a bellows, which in turn facilitates brain cooling. They noted that the actual function of sinuses is still the subject of debate, and this theory may help clarify their purpose.
They said their theory that yawning helps cool the brain has medical implications. For example, excessive yawning often precedes seizures in people with epilepsy and pain in people with migraine headaches.
Doctors may be able to use excessive yawning as a way to identify patients with conditions that affect temperature regulation.
"Excessive yawning appears to be symptomatic of conditions that increase brain and/or core temperature, such as central nervous system damage and sleep deprivation," Gallup said in the news release.
The above story is extracted by The Zestfulness Team from materials in the University of Maryland at Baltimore, news release, Nov. 14, 2011
The article has been published in the current edition of the journal Medical Hypotheses: Gallup AC, Hack GD. Human paranasal sinuses and selective brain cooling: A ventilation system activated by yawning? Med Hypotheses. 2011 Dec;77(6):970-3. Epub 2011 Sep 8.Zestzfulness pages are AnswerTips-enabled, allowing you to access definitions and fast facts on obscure words, slang and scientific jargons. Simply double-click anywhere and get instant definitions.