What is it that makes us yawn?

Answer 1

we always think that yawning is caused by lack of sleep. but i've read in a science book somewhere, i forgot the title, it means that you need more oxygen in your body,specifically your brain, which triggers our yawning reflex. i don't know the medical term for yawning, anyway, that's the real deal about it.

Answer 2

need for more oxygen or a psychological response
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Interesting Yawning Facts
The average yawn lasts about six seconds.
Your heart rate can rise as much as 30 percent during a yawn.
55 percent of people will yawn within five minutes of seeing someone else yawn.
Blind people yawn more after hearing an audio tape of people yawning.
Reading about yawning will make you yawn.
Olympic athletes often yawn before competition.

Answer 3

THE TRUTH IS that we don’t completely understand why people, or animals for that matter, yawn. It’s widely assumed that yawning occurs because we are tired or bored or because we see someone else doing it, but there isn’t any hard evidence to support these beliefs.

The most plausible explanation, and the one that is taught in medical school, is that we yawn because oxygen levels in our lungs are low. Studies have shown that during normal, at-rest breathing, we don’t use anywhere near our lung capacity; for the most part, we just use the air sacs at the bottom of the lungs. If the air sacs, called alveoli, don’t get fresh air, they partially collapse and the lungs stiffen a bit. As a result, it’s believed, our brain prompts the body to either sigh or take a yawn to get more air into the lungs.

But certain aspects of yawning remain even more mysterious. Fetuses, for instances, have been observed yawning in the womb, yet it’s known that they don’t take oxygen in through their lungs. And yawning seems to be a symptom of multiple sclerosis and other medical conditions, for reasons unclear.

Another puzzling phenomenon is that some male animals, men included, yawn in association with penile erection (although it’s presumptuous to assume they’re bored with their sex lives).

Answer 4

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

Answer 5

Other people yawning.

Answer 6

when you yawn it means your brain needs oxygen

Answer 7

yawning is caused by the lack of o2 in your brain..

Answer 8

lack of oxygen t othe brain

Answer 9

lack of oxygen to the brain.

Answer 10

Need for sleep hunger