(1) Warming effect: mainly depends on the heat dissipation of nasal mucosa blood vessels. It's similar to the principle of air conditioning, except that instead of condensate or something, it's boiling blood. And the three turbinates are arranged like fins. When the air passes through here, the blood will quickly heat the air. Nerve reflex can also regulate vasodilation or contraction, and control the temperature change by regulating blood flow to keep it relatively constant. According to scientists' research and measurement, in winter, outdoor air at minus 7℃ can be heated to 28.8℃ through the nasal cavity. In spring, the outside air of 12℃ can be heated to 35.6℃ by nasal cavity. How, the efficiency of the nose is very high!
(2) Humidification: The air contains moisture, but it is still too dry for the human body and does not meet the needs of the human respiratory tract. Humidification of nasal cavity can meet this need. The humidification of nasal cavity is also accomplished through nasal mucosa. In addition to blood vessels, mucous membranes also contain many mucus glands, which secrete liquids like sweat glands of the skin. This secretion activity can basically ensure that only 40% humidity air outside will reach 98% when it is sucked into the throat. Some scientists have also measured that the water secreted by the turbinate mucosa one day and one night can fill more than two beer bottles (1000 ml or more). Enough!
(3) Filtering and cleaning: The nose has four lines of defense to deal with air containing dust, bacteria, viruses or molds. The first line of defense is the nose hair in front of the nose hole, which, like thorns in the hole, can block the larger dust. The second line of defense is reflex sneezing. Sneezing doesn't just happen after a cold. It also happens after the nasal cavity is stimulated by foreign bodies (such as dust), which is the process of expelling foreign bodies. So when sneezing, don't point your nose at others. This is unhealthy and impolite. The third line of defense is the most important, that is, cilia movement in mucosa. There is a layer of mucus blanket on the surface of mucus cilia, which can stick bacteria or dust particles and send them to the back nostril for discharge. For example, cilia in nasal mucosa are like aquatic plants in rivers, and the mucus blanket on its surface is like water. They always swing or flow in one direction, sending things floating on the water downstream. The fourth line of defense is lysozyme, interferon and secretory IgA contained in mucus layer. They are like fungicides in water, which can inhibit many bacteria and viruses! After the baptism of the above four lines of defense, the polluted air will become clean.
2, the respiratory function of the nose. The nose is used to breathe first, so how does air pass through the nasal cavity?
There is a place behind the nasal vestibule called nasal threshold, which is an annular "threshold" surrounded by structures such as the front end of the inferior turbinate, and is the narrowest place of the nasal cavity. When air passes through it, it will feel resistance. Doctors call it "nasal resistance". The role of nasal resistance, one is to prolong the inhalation time, and the chest cavity expands faster than the speed of gas entering the lungs, thus forming negative pressure in the chest cavity, helping the lungs to expand and inhale more air; When exhaling, air stays in the lungs for a longer time, which is helpful for gas exchange in the lungs; The second is to participate in nasal lung reflex and nasal heart reflex. The so-called nose-lung reflex and nose-heart reflex are the problems of the nose, which affect the function of the heart and lungs in some ways. For example, some people have allergic rhinitis and bronchial asthma; Some people have a stuffy nose and increased respiratory resistance, which affects lung ventilation. At the same time, the amount of blood returning to the heart is insufficient, and the cardiac output is also reduced accordingly. Visible nose is still very important!
In addition, when the air passes through the nasal threshold, it will be divided into two ways. One goes straight into the lungs. It is an important part of our oxygen exchange. Because of its large contact area with the nasal cavity, it is also the part that plays the role of heating and humidifying. Doctors call this airflow route laminar. The other route is under the nasal cavity tumbling, which doctors call turbulence. It mainly assists the settling of harmful particles in the air, and plays a role in filtering and cleaning the nose.
3. Other functions of the nose. Besides protecting human body and respiratory function, nose should smell fragrant and smelly, which is the function of smell. When talking and singing, the nasal cavity and paranasal sinuses can also resonate, producing rich nasal sounds, which is the resonance function of the nose. In addition, the turbinate circulation is beneficial to sleep and turn over, relieving fatigue. Sinus can also reduce the weight of the skull, cushion the impact of violence on the brain, maintain head balance and so on.