The nasal cavity is the front station of the respiratory system. Breathing is gas exchange inside and outside the body, inhaling gas with high oxygen content and discharging metabolic waste gas with high carbon dioxide content. In fact, although the respiratory tract of the human body grows in the body, it is "outside the body". There are some differences in temperature, humidity and content of air in vitro and in vivo. The moist environment in the nasal cavity can play the role of heating and humidification.
In different latitudes and climatic environments around the world, the structure of human nose and even nasal cavity is slightly different. Europe is cold, and cold will stimulate lung function, which may lead to sudden stop of lung function in extreme cases. Therefore, Europeans have longer noses and deeper nasal cavities, which can be heated to higher temperatures when air flows past. In contrast, Africans have a flatter nose and a smaller nasal cavity.
The flow of gas will also increase the evaporation of water, and the nasal mucosa may dry and die due to lack of body fluids, so the nasal epithelium is often updated to maintain the integrity of the nasal mucosa. At the same time, these mucus components can attach to the dust particles in the gas, and also make some bacteria attached to the dust particles unable to enter the human body, which is the physical barrier of human immunity.
Therefore, the components of nasal mucus are mucus normally secreted by human body, epithelial cells shed from nasal cavity, old particles and some microorganisms, and the content is very rich. The frequency of nasal application is very high, and people breathe about 20 times a minute, so a lot of nasal mucus is produced every day, about 1000ml, but most of it is swallowed unconsciously by us. Even if some harmful bacteria remain, they will be destroyed by gastric acid because they enter the stomach. Nasal cavity plays an important role in preventing respiratory diseases, relying on mucus.
When the cold is cold, the nose is white and thin, and when the wind is hot, the nose is thick and yellow. In fact, different pathogens that infect the upper respiratory tract lead to different colors and other characteristics of nasal mucus. There is no obvious difference in the amount of nasal mucus in a normal person's day, but those with rhinitis or pharyngitis have more nasal mucus and sputum, mainly because of bacterial lesions in the nasal cavity and pharyngeal gorge, which constantly stimulate the mask to secrete mucus.
The nasal cavity plays a role in breathing, human immunity and sense of smell. Mucus produced by mucous membrane is a measure to ensure the normal execution of these functions. As long as a certain amount of nasal mucus is produced or will be produced, whether it is ancient or modern, the quantity and nature of nasal mucus is one of the important basis for judging some respiratory diseases.