How came when you yawn you get tears in your eyes?
543983
same thing for me too,,its regular and you cant do any thing about it..
337700
From a lack of oxygen. Yawning is when your blood circulation slows down i.e at high altitude average people yawns at least 7 times per minutes.\n\nAlso a sign that adrenaline is slowing down and if inactive, the body will shut down.  Involuntary but necessary, seeing people doing so reminds us that the body needs it...
378590
People yawn when the level of carbon dioxide in their blood is a little too high, this is bad and eventually can cause unconsciousness.  To stop this you yawn, yawning means you take in a big gulp of oxygen and expel carbon dioxide.  They are thought to be contagious because if I see you yawning my brain thinks.. uh oh there is too much carbon dioxide in this room that person is already feeling the effects, to protect myself I will yawn too!\n\nBy the way you also yawn if you're tired because you're breathing naturally slows which makes carbon dioxide build up more easily.  You will yawn when you are tired to expel this excess carbon dioxide!
3436
Tears drain away from each eye along two channels marked by a tiny opening at the inner edge of each lid. The channels lead to the lacrimal sac at the side of the nose, which is why your nose runs when you cry. Yawning exerts pressure on the lacrimal sac causing normal tearing.
321997
Cause when you yawn, you are thought to release carbon dioxide, and when somebody else gets the carbon dioxide, then they have to release it.  Another theory is, a long time ago when humans first existed, it meant it was time to go to sleep, so everyone would know toy go to sleep.  Isn't that so cute?  ^.^
142620
No..A yawn is something your body does when it needs a little more oxygen. Like if you were in a small area your body will yawn to get as much oxygen it can and remove the carbon dioxide .. all you have to do is take a deep breath and go about your business..
1174829
because our bodies are low on oxygen... we yawn to take in a big gulpl of fresh oxygen to awaken our sleepy oxygen deprived brain... you know it does a body good.
304410
I can't remember where I heard this but someone told me it's an empathetic response. Like the more in tune you are to others feelings, the more likely you are to yawn when you see someone else do it.
819788
Sympathetic yawning is a good answer.  But a yawn is actually a deep inhale, it may be that for some reason there is a slightly lower amount of oxygen in the air and that particular location and you are both simply trying to get more air.
397407
Though the other answers are right (that yawning occurs to signal tiredness when the brain demands extra oxygen due to slipping performance), I would like to add another related comment.\n\nI recently read in the newspaper that scientists are discovering that yawning is a signal of compassion.  Researchers conducted studies in which participants watched videos of people yawning and the researchers measured the time between the yawn of the person on the video and the ensuing yawn of the study participant.  They then somehow effectively linked this elapse to compassion; what they stated was that the quicker you yawn after you see someone else yawn, the the more compassionate you are.\n\nRegretfully, I don't know the web address of the article, which I found intriguing, but I think it is worth your time to investigate.
14485
At the corner of our eye is a tube leading to the nose, at the top of which is a small container called a lachrymal sac. This sac is full of tears. When we yawn the muscles in our face squeeze this sac and tears spill out from the eyes.  This also explains why your nose runs when you cry.
1159613
Ahhh... the age old question. lol\n\nThere are a number of theories. One is that when someone yawns, they take oxygen out of the air, and we need the oxygen so we yawn to get the oxygen we need. I'm not sure about that one. I think its just a joke.\n\nA more likely theory is that it relates back to the herd instinct. You know, monkey see, monkey do.
792582
A yawn is in response to too much CO2 in the blood stream.  When you yawn there is a negative feed back loop in operation which tells the diaphram to contract (take a breath) because there is too much CO2......the yawn actually increases CO2.\nThe sneeze is due to irritation in the beginning of the respiratory tract, it expells such things as dust, bacteria and other irritants from your nose and sinuses.\nA hiccup is a sligh malfunction or mistiming if you will of the glottis which is a membrane that closes in your throat to prevent food from going into your lungs when you swallow.  Whenyou ge tthe hiccups it starts to close while you are taking a breath or expelling a breath.  It just takes a bit of time for your body to reset when it closes
309172
padillio is right. it is just a mental thing, and she is also right in saying that it is because of a lack of oxygen. it is also associated with being tired b/c when you're body is fatigued or tired, you're breathing slows down and you get a lack of oxygen. yawning is an involuntary muscle movement to make you breath heavily and take in more oxygen. anyway, that's pretty much it.
411411
Crying or weeping is increased production of tear due to strong emotional stress or pain. This practice is not restricted to negative emotions; many people have been known to cry when extremely happy. \n\nIn humans, emotional tears can be accompanied by reddening of the face and sobbing — cough-like, convulsive breathing, sometimes involving spasms of the whole upper body. Tears brought about by emotions have a different chemical make up than those for lubrication. As one of your other readers have pointed out crying releases a lot of stress and carries with it harmful chemicals away from your body.\n\nHave you not heard the phrase, "cry your heart out"... it makes good sense to cry out your feelings as it is bad to hold in emotions.... they say holding back really builds up toxins that can even lead to cancer.
643005
A yawn is a reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or from boredom. The word "yawn" has evolved from the Middle English word yanen, an alteration of yonen, or yenen, which in turn comes from the Old English geonian. 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.\n\nCauses of yawning\nAn indication of tiredness, stress, over-work or boredom. \nAn action indicating psychological decompression after a state of high alert. \nA means of expressing powerful emotions like anger, rejection or apathy. \nA sign that one is not breathing deeply, and not receiving enough oxygen through the body. \nA 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.\n\nA 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 documented that this effect does not exist ("Yawning" by Robert R. Provine, pages 532-539, American Scientist, November-December 2005, Vol 93, No. 6). [1]. 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.\n\nAnother theory is that yawning is similar to stretching. Yawning, like stretching, increases blood pressure and heart rate while also flexing many muscles and joints. 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.\n \nThe yawn reflex is often described as contagious: if one person yawns, this will cause another person to "sympathetically" yawn.[2] The reasons for this are unclear; however, recent research suggests that yawning might be a herd instinct.[3] 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, thus proclaiming, "don't attack while I am sleeping..." The contagion of yawning is interspecific (i.e., try yawning in front of your dog). Yawning in public is generally regarded as impolite in the West, but came into fashion in polite French society for a brief period in the late 18th century. 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".\n\nAdelie Penguins employ yawning as part of their courtship ritual. Penguin couples face off and the males engage in what is described as an "ecstatic display," their beaks open wide and their faces pointed skyward.\n\nYawning in Popular Culture\nCertain superstitions surround the act of yawning. The most common of these is the belief that it is necessary
829322
1- During a yawn, there is a slight increase in pressure inside the skull (likely caused by slight increases in the amount of oxygen taken in during a deep yawn). This causes the cerebrospinal fluid (CSF), the fluid that surrounds the brain and flows through the brain's ventricle system, to be forced out faster than normal. That fluid enters the lachrymal (tear) system. That increase in fluid pushes out the tears.\n\n2 - the more simplistic reason may be that when you yawn you scrunch up a bunch of facial muscles. That causes the tear glands and ducts to be squished, forcing out some tears.\n\n\nTalks about yawning as well:\nhttp://en.wikipedia.org/wiki/Yawn#Causes_of_yawning