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Why do people shed tears when they yawn? Why do you close your eyes and shed tears when you yawn?

Xiaobian has always been very curious, why in yawning when eyes will be closed, but also tears. Yawn on yawn, why will it involve tears? Next and Sihai Xiaobian together to rise knowledge.

Why do people shed tears when they yawn? Why do you close your eyes and shed tears when you yawn?

There is a lacrimal gland in the orbit above the two eyes. In addition to sleep, the lacrimal gland is secreting tears all the time. Usually, the lacrimal gland secretes very few tears. These tears flow into the nasal cavity through the lacrimal passage, so people can hardly feel their tears.

When a person yawns, he opens his mouth wide, and a stream of gas rushes out of his mouth. At this time, the pressure in his mouth is very high, and the pressure in his nose also increases. The passage of tears is temporarily blocked, so he has to burst into tears.