why do we yawn?

Question

i no y we yawn i was just wondering if any 1 else out there has the write answer

Answer 1

A yawn (synonyms chasma, oscitation from the Latin verb oscitare, to open the mouth wide[1]) is a reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or from lack of stimulation. Pandiculation is the term for the act of stretching and yawning. Yawning is a powerful non-verbal message with several possible meanings, depending on the circumstances. It is also claimed to help increase the state of alertness of a person. The exact causes of yawning are still unknown.

Causes of yawning
1. An indication of tiredness, stress, over-work, or boredom.
2. An action indicating psychological decompression after a state of high alert.
3. A means of expressing powerful emotions like anger, rejection, apathy, or tedium.

A yawn can express strong anti-social messages, and so in some cultures people try to mute or mask them by placing a concealing hand over the yawning mouth.

A previous long-standing hypothesis is that yawning is caused by an excess of carbon dioxide and lack of oxygen in the blood. The brain stem detects this and triggers the yawn reflex. The mouth stretches wide and the lungs inhale deeply, bringing oxygen into the lungs and hence to the bloodstream. It is almost certain, however, that this hypothesis is not correct. One study has documented that this effect does not exist.[2]

A more recent hypothesis is that yawning is used for regulation of body temperature. Another hypothesis is that yawns are caused by the same chemicals (neurotransmitters) in the brain that affect emotions, mood, appetite and other phenomena. These chemicals include serotonin, dopamine, glutamic acid and nitric oxide. As more of these compounds are activated in the brain, the frequency of yawning increases. Conversely, a greater presence in the brain of opiate neurotransmitters such as endorphins, reduces the frequency of yawning. Patients taking the serotonin reuptake inhibitor Paxil (Paroxetine HCl) have been observed yawning abnormally often. Another theory is that yawning is similar to stretching. Yawning, like stretching, increases blood pressure and heart rate while also flexing many muscles and joints. It is also theorized that yawning helps redistribute an oil-like substance which coats the lungs and aids breathing. Some have observed that if you try to stifle or prevent a yawn by clenching your jaws shut, the yawn is unsatisfying. As such, the stretching of jaw and face muscles seems to be necessary for a good yawn.

Some movements in psychotherapy such as Re-evaluation Counseling or co-counselling believe that yawning, along with laughter and crying are means of "discharging" painful emotion, and therefore can be encouraged in order to promote physical and emotional healing.

Contagiousness
The yawn reflex is often described as contagious: if one person yawns, this will cause another person to "sympathetically" yawn.[3] The reasons for this are unclear; however, recent research suggests that yawning might be a herd instinct.[4] Other theories suggest that the yawn serves to synchronize mood behavior among gregarious animals, similar to the howling of the wolf pack during a full moon. It signals tiredness to other members of the group in order to synchronize sleeping patterns and periods of activity. It can serve as a warning in displaying large, canine teeth. This phenomenon has been observed among various primates. The threat gesture is a way of maintaining order in the primates' social structure. The contagion of yawning is interspecific, for example a human yawning in front of a pet dog can incite the dog to yawn as well. Oddly, sometimes sympathetic yawning may be caused by simply looking at a picture of a person or animal yawning, or even seeing the word "yawn".

You could get more information from the link below...

Answer 2

Why do we yawn? Dr. Barry Make, a pulmonologist at National Jewish Medical and Research Center in Denver, says the answer is not because we are tired or bored — although that’s the common perception. Read on for his explanation.

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.



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 3

Richard b I'll have to say that many women respond to penile erection by yawning too. This question has made yawn - why is yawning suggestible?

Answer 4

An indication of tiredness, stress, over-work, or boredom.
An action indicating psychological decompression after a state of high alert.
A means of expressing powerful emotions like anger, rejection, apathy, or tedium.

Answer 5

Isn't it due to lack of oxygen to the brain? ... although if that is the case why are yawns contagious ;o)

xx

Answer 6

It's a unconditioned response signal from the brain that usually happens from lack of sleep. Some people do it when they're bored, but that too is unconditioned because, in that case, it is caused by external stimuli around the person.

Answer 7

look i dont know the answer,but the answer that came form the person saying it comes from our animal instincts is general ,that is assuming that we come from aniamls and that the theory of evolution has been proved ,so u cant say we came from animals that wd be saying that the theory of evolution has been proved which it hasnt ,it has been disproved though,its jus a theory remember,thats if we r talking truthfully or jus goin to believe wot they say there are many things unansewred,hence the theory of evolution ..

Answer 8

It forces us to take a big breath and brings in more oxygen to our lungs then into our bloodstream then to our brain to help wake us up.

Answer 9

Because of a lack of oxygen

Answer 10

To take in more air and therefore more oxygen than normal breathing.