As we all know, tears are a colorless, clear, slightly salty liquid that comes out of the eyes. Snot is a colorless or white liquid secretion that comes out of the nose.
But how do tears and snot mix together? There is a phenomenon you must be familiar with: when crying, not only to wipe the tears but also to wipe the snot. The sadder you cry the more tears flow, and the more snot. As the saying goes, “a snotty nose and a tear” is a vivid depiction of this phenomenon. It can be seen that for a long time, people have been paying attention to the relationship between tears and snot.
There is a very thin tube between the eyes and the nose, called the nasolacrimal duct. The eyes and nose are connected to each other by the nasolacrimal duct. The nasolacrimal duct is about 15-20 mm long, and tears flow continuously into the nasal cavity through this duct. This flow is not simply a natural phenomenon of water flowing downward, but rather a “pump” effect. A lot of muscles around the eyes, these muscles are scattered alternately contracted and relaxed, thus generating the effect of positive and negative pressure, that is, the pumping effect, scattered tears pumped into the nasal cavity. Therefore, it is normal for tears to drain into the nasal cavity. However, we usually do not feel the tears flowing into the nasal cavity, because these tears are quickly mixed with the liquid in the nasal cavity to humidify the air daily through the nasolacrimal ducts to the nasal cavity.
However, when the nasolacrimal duct becomes blocked, the tears cannot flow into the nasal cavity and can only spill outward from the eyes. This is often caused by dacryocystitis, which narrows and blocks the nasolacrimal duct. So that no matter what time also regardless of whether there are emotional changes will have tears out of the eyes, do not know the details of the people also think that the love of emotional performance!