Some snots are actually tears. These tears are produced by lacrimal glands, some of which flow to lacrimal canaliculus, and then flow to nasal cavity through nasolacrimal duct, becoming a part of nasal mucus.
A small part evaporated, a small part dried up and became booger, but most of it was swallowed by us. There are cilia on the nasal mucosa, which will swing back and forth and the nose will be sent back to the pharynx. Because the nasal cavity and esophagus are connected, most nasal mucus is swallowed unconsciously by us.
A healthy person's nose has to handle hundreds of milliliters of snot every day! Goblet cells produce a large number of mucins. After mucin is released outside the cell, it absorbs a lot of water, and its volume can expand 600 times! The goblet cells only need to produce 1 ml mucin a day, which is enough to meet the normal needs of the nasal cavity.
A healthy person's nose handles hundreds of milliliters of snot every day. But we don't have runny noses every day. Where did you get so many runny noses? A small part evaporated, a small part dried up and became booger, but most of it was swallowed by us.
There are cilia on the nasal mucosa, which will swing back and forth and the nose will be sent back to the pharynx. Because the nasal cavity and esophagus are connected, most nasal mucus is swallowed unconsciously by us. Although it sounds disgusting, it is harmless to human body. Besides water, there are protein, carbohydrates, salt and some exfoliated cells.
Protein in nasal mucus is mainly mucin, which is a kind of glycoprotein, covered by a "sugar coating" composed of carbohydrates, so that it can absorb a lot of water. Other protein in nasal mucus include antibodies and lysozyme, which can kill bacteria and viruses. These ingredients will be digested and absorbed by the gastrointestinal tract as nutrients. Of course, nasal mucus also contains sticky dust, pollen and microorganisms, but these impurities can be treated by gastric acid and will not cause trouble to the body.