UC知道翻译一下,请不要用软件!
来源：百度知道 编辑：UC知道 时间：2024/06/08 00:21:03
人的眼泪时时刻刻都在分泌，在眼球表面流动。可是平时分泌的泪液很少，而且是紧沿着眼球表面和眼皮里面微细空隙中流动，所以，你不会觉得泪水在流动。
然而，在你眨眼的一刹那间，这些眼球表面的泪水就被吸到眼泪的下水道——鼻泪管里去了。别小看这条不太长的细管子，它却是眼泪通到鼻腔的唯一要道。泪腺不断分泌泪水，鼻泪管不断排泄泪水，所以平时人是不会流泪的。
人在打哈欠的时候嘴巴张得很大，尺可能多地让气呼出体外，为的是呼出二氧化碳，吸进氧气。随着打哈欠的动作一股气体有力地从嘴巴呼出。面颊部、舌和咽喉部肌肉紧张收缩，这时口腔及鼻腔的压力增大。鼻腔压力增高的结果就会一时性地阻挡鼻泪管排泄泪水的工作，“下水道”不通，泪水流不下去，积在眼睛里的泪水就越来越多。就会两眼泪汪汪的，最后夺眶而出，流到脸上来了。
其实，不仅打哈欠会流眼泪，人在大笑、打喷嚏、咳嗽、呕吐时，也会引起这样的流泪，道理也都是相同的。
Sleepy time Association giving the sky. Jury is a fight, the Federation of tears in the eyes of the bark, why would people giving tears?
The secretion of tears all the time, the surface flow in the eye. But rarely peacetime tear secretion, but tight along the eyeball and eyelid inside surface micro-flow gap, so you will not find in tears flow.
However, in a twinkling of an eye you blink of an eye, the eye surface fresh tears were tears on the sewer - nasolacrimal duct again. Other belittle this not too long a small tube, it is tears - the only thoroughfare to the nasal cavity. The lacrimal gland secretion of tears, the nasolacrimal duct excretion tears, so usually the people will not shed tears.
When people in Nepal very big-mouth, feet and more likely to allow gas exhaled in vitro in order to exhaled carbon dioxide, sucked into oxygen. Along with giving a gas moves from the mouth forcefully exhaled. Cheek, tongue and throat muscles tense contract