i know we yawn when we're tired but what IS a yawn anyway n what causes it?
2007-06-04 07:20:18 · 15 answers · asked by Cayleigh B 2 in Health ➔ General Health Care ➔ Other - General Health Care
The Physiological Theory -- Our bodies induce yawning to drawn in more oxygen or remove a build-up of carbon dioxide. This theory helps explain why we yawn in groups. Larger groups produce more carbon dioxide, which means our bodies would act to draw in more oxygen and get rid of the excess carbon dioxide. However, if our bodies make us yawn to drawn in needed oxygen, wouldn't we yawn during exercise? Robert Provine, a psychologist at the University of Maryland, Baltimore County, and a leading expert on yawning, has tested this theory. Giving people additional oxygen didn't decrease yawning and decreasing the amount of carbon dioxide in a subject's environment also didn't prevent yawning.
The Evolution Theory -- Some think that yawning is something that began with our ancestors, who used yawning to show their teeth and intimidate others. An offshoot of this theory is the idea that yawning developed from early man as a signal for us to change activities.
The Boredom Theory -- In the dictionary, yawning is said to be caused by boredom, fatigue or drowsiness. Although we do tend to yawn when bored or tired, this theory doesn't explain why Olympic athletes yawn right before they compete in their event. It's doubtful that they are bored with the world watching them.
The simple truth is that even though humans have been yawning for possibly as long as they have existed, we have no clue as to why we do it. Maybe it serves some healthful purpose. It does cause us to draw in more air and our hearts to race faster than normal, but so does exercise. There's still much we don't understand about our own brains, so maybe yawning is triggered by some area of the brain we have yet to discover. We do know that yawning is not limited to man. Cats, dogs, even fish yawn, which leads us back to the idea that yawning is some form of communication.
2007-06-04 07:23:37 · answer #1 · answered by Shaunda W 3 · 0⤊ 0⤋
We yawn when our brain needs more oxygen which is why when we have to concentrate for long periods of time we yawn more. If you rub the top of your cheek bones with 2 fingers on each side you can make your self yawn which is meant to be good for you if you are about to start a long task or one that requires a lot concentration. YAWN! They are catching too!
2007-06-04 07:24:29 · answer #2 · answered by Anonymous · 0⤊ 0⤋
When we breathe shallowly at a regular pace, over a period of time, the alveoli (or small sacs in our lungs where oxygen exchanges with carbon dioxide) at the edges of the lung don't get expanded fully and collapse. This is called "atalectasis". As this happens more and more, carbon dioxide gradually builds up in the bloodstream (because it is harder for it to "find" an alveolus to use to "escape" out of).
The increase in carbon dioxide levels triggers a sensor in the brain to yawn -- which causes the diaphragm to pull down more than usual, which causes the lungs to expand more fully, which pulls the alveoli open again -- which allows the carbon dioxide to be fully released.
Thus, a yawn.
The more tired we are, the more shallowly we breathe.
Notice, when you exercise, you are breathing pretty deeply -- and you don't generally yawn.
2007-06-04 07:27:30 · answer #3 · answered by julia.hoover 3 · 0⤊ 0⤋
A yawn is a reflex of simultaneous inhalation of air and stretching of the eardrums, followed by exhalation of breath. Hypothesized causes of yawning: 1. The deep inhalation during a yawn is a means of preventing alveolar collapse. 2. The deep inhalation while yawning stretches type II alveolar pneumocytes, which release the surfactant dipalmitoylphosphatidylcholine (DPPC) into the layer of fluid on the alveolar surface. 3. A means of cooling the brain. 4. An action used as an unconscious communication of psychological decompression and stress after a state of high alert. 5. An excess of carbon dioxide and lack of oxygen in the blood. 6. A way of displaying (or indicative of) apathy. 7. Tiredness. 8. A means of equalizing middle ear pressure. 9. Need of food or hunger/ appetite due to reduced level of glucose supplied to the brain. 10. To cool the body, such as after repeated exercise. 11. To moisten and lubricate the sclera and cornea of the eye, or stimulate the tear ducts. 12. To purge the lymphatic system before or after sleep
2016-05-21 02:30:08 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Even if you show the word to someone on a piece of paper, 9 times out of 10..they will actually do it, see for yourself.
YAWN
2007-06-05 02:37:58 · answer #5 · answered by Shaun of Egg 2 · 0⤊ 0⤋
Yeah!! Lack of oxygen!! But why do people yawn when they see somebody else yawn?
2007-06-04 07:33:00 · answer #6 · answered by Polar Molar 7 · 0⤊ 0⤋
Lack of oxygen makes us yawn
2007-06-04 07:29:37 · answer #7 · answered by Anonymous · 0⤊ 0⤋
When we yawn its our body asking us for more fresh oxygen.. when we yawn our body draws in a... sharp intake of breath this delivers more oxygen around the body and brings us back to life again.. there you know now lol xxxxxxxxx
2007-06-04 07:24:07 · answer #8 · answered by Anonymous · 1⤊ 0⤋
You yawn for two reasons. One is the lack of enough sleep ans two is lack of oxygen intake to your lungs.
2007-06-04 07:25:37 · answer #9 · answered by milldoc 3 · 0⤊ 0⤋
your question made me yawn NOT because its boring but even when i think about yawning i do it!!!!x
2007-06-04 07:23:27 · answer #10 · answered by BscHons 6 · 0⤊ 0⤋