在眼睛上眼睑的外上方有一个泪腺,眼泪就是泪腺分泌出来的液体。鼻子和眼睛之间有一个通道,叫鼻泪管。在人们感到伤心或委屈的时候,常常会哭得一把鼻涕一把泪。这是因为,眼泪由泪腺分泌出来后,先经过上下泪小管进到泪囊,再经过鼻泪管进入鼻腔。平时,泪腺分泌的眼泪比较少,我们感觉不 There is a lacrimal gland on the outside of the eyelids on the eye, and tears are the liquid secreted by the lacrimal glands. There is a passage between the nose and the eye called nasolacrimal duct. When people feel sad or grievances, often cry a snot a tear. This is because tears were secreted by the lacrimal gland, the first through the lacrimal duct into the lacrimal sac, and then through the nasolacrimal duct into the nasal cavity. Usually, tear secretion of tears less, we do not feel