On Tue, 20 May 2008 05:46:33 GMT, WingedMessenger <Boy@FlyingHigh.com>
wrote:
>"::darkshadows::" <blood@thirsty.net> wrote in
>news:btb434h2b7cfi6n7t65daiumfd03hocr0i@4ax.com:
>
>>
>>
>> Why do we yawn?
>>
>>
>> animals for that matter, yawn.
>>
>> evidence to support these beliefs.
>>
>> Scientists do not purport to know all of the biological mechanisms of
>> the yawn, but tend to agree that a yawn is an involuntary respiratory
>> reflex, which regulates the carbon dioxide and oxygen levels in the
>> blood.
>>
>> Technically, a yawn is the reflex opening of the mouth followed by the
>> deep inhalation and slow exhalation of oxygen.
>>
>> The very act of yawning is but one of a number of involuntary reflexes
>> controlled by the spinal and nerve centers.
>>
>> Scientists speculate that the onset of a yawn is triggered either by
>> fatigue, or by sheer boredom as, at those times, breathing is shallow,
>> and little oxygen is carried to the lungs by the oxygen-toting
>> cardiovascular system.
>>
>> When one yawns, his or her alertness is heightened, as the sudden
>> intake of oxygen increases the heart rate, rids the lungs and the
>> bloodstream of the carbon dioxide buildup, and forces oxygen through
>> blood vessels in the brain, while restoring normal breathing and
>> ventilating the lungs.
>>
>> This quite plausible theory of yawning falls short of explaining many
>> aspects of yawning. Scientists explain away the "contagious" nature of
>> yawning, that is when one person's yawn triggers another nearby to
>> yawn, as due to the power of suggestion, but are at a loss when
>> attempting to explain why yawning occurs excessively in patients with
>> lower brainstem damage or with multiple sclerosis.
>>
>> Other unlocked mysteries include why fetuses in the womb yawn, when it
>> is a well-known fact that they do not intake oxygen into their lungs
>> until after live birth, or why individuals with high concentrations of
>> oxygen in their blood streams yawn.
>>
>> Until these questions are answered, do not assume that a person who
>> yawns in your presence is bored with what you are saying, or suffers
>> from exhaustion. Simply be pleased that he or she is not bored to
>> death.
>>
>>
>
>Let him yawn in peace, is nothing sacred LOL.
>
>Mercury.
It would be if it were not for all the flies he is catching.
darkshadows
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