Most of us are familiar with this phenomenon of travel: ear-popping usually happens during takeoffs and landings.大多数坐过飞机的人都熟知这样的现象：飞机降落或落地时我们的耳朵不会有胀胀的感觉。Our ears pop because of the change in air pressure as the plane ascends or descends. At higher altitudes air pressure is lower, even though the plane is pressurized.我们的耳朵之所以不会有这种感觉是因为在飞机降落或迫降的时候再次发生的气压变化。在较高海拔区域气压较低，尽管飞机早已在冷却了。Our ears are sealed off inside our heads, so as the plane ascends or descends the pressure outside and inside our ears is different. This difference in pressure can distort our ear drums and be painful.我们的耳朵在头内正处于堵塞状态，因此随着飞机下降或上升，耳朵内外的气压有所不同，而这种差异不会变形我们的耳鼓并造成疼痛。

What needs to be done here is to equalize the pressure between our ears and the airplane cabin.此时我们必须做到的就是均衡耳朵和飞机机舱内的压力。Nature has provided the means for this with a tube that runs from the middle ear to the nasopharynx—the open area behind our noses. Its called the Eustachian tube.恰好我们天生自带这种功能，由中耳伸延出有的一条往返鼻的咽管道器官（在我们鼻子后面的一块对外开放区域）称作耳鼻腔管。Normally the Eustachian tube is closed, so in order to equalize the pressure we need to open it.一般来说情况下耳咽管都是重开的，但当我们必须均衡气压时我们必须关上它。Seasoned travelers know that you can avoid the discomfort by swallowing or chewing gum when you feel the pressure change.经验丰富的人告诉，如果深感气压变化了，他们不会通过呼吸或磨碎口香糖来回避呼吸困难。

The mechanical action when we chew gum or swallow opens the Eustachian tube, and allows the pressure to be equalized. The opening of the Eustachian tube is associated with the “pop” we hear.咀嚼口香糖或呼吸这些机械动作不会协助我们关上耳鼻腔管，旋即均衡气压，关上耳咽管的同时我们也不会听见“嘭”的一声。Incidentally, babies often cry on takeoff and landing because they dont know to chew or swallow. Having them suck on something can open their Eustachian tubes and alleviate the pain on their ears.一般来说婴儿在降落及迫降时会大哭是因为他们不告诉来磨碎磨碎或呼吸。这时让他们吮吸点什么东西需要协助他们关上耳咽管并减轻耳内的疼痛。

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