The nose is an important part of our face, located in the second ring of the face within the prime location, is the door of the human respiratory tract. The nose is also called the “king of the face”, Chinese medicine has “the upper diagnosis in the nose, the lower examination in the abdomen”, which shows the importance of the nose for our body. When people think of the nose, they naturally think that the nose is not just breathing and smelling. In fact, the nose has many powerful functions, much more than just breathing and smelling so simple. The nose is divided into 3 parts: the external nose, the nasal cavity and the paranasal sinuses. The nasal cavity is a narrow cavity with a narrow top and a wide bottom, starting from the anterior nostril and ending at the posterior nostril, connected to the nasopharynx, with a large area of nasal mucosa and curved complex nasal passage, containing special olfactory cells and a rich capillary network, cilia, nasal mucosa contains a wealth of mucus glands. Plasma glands, mixed glands and cup cells can secrete a certain amount of liquid, making the mucous membrane surface covered with a mucus blanket that keeps moving with the movement of cilia. The sense of smell arises from the mucous membrane in the nose with olfactory function, which is medically called the olfactory zone. The nasal septum separates the nasal cavity into two cavities, the left and the right, and each side of the nasal cavity includes two parts: the nasal vestibule and the intrinsic nasal cavity. The nasal cavity is connected to the outside world through the nasal aperture forwards and backwards through the nasopharynx, called the posterior nasal aperture. Each side of the nasal cavity is further divided into two parts: the nasal vestibule and the intrinsic nasal cavity. The structure of the nose is so complex that it naturally has many functions: 1, breathing function. Breathing is the most important function of the nose, air through the nose, we can feel the presence of air, but through the mouth we can not feel the presence of air. 2.Sense of smell function. There are olfactory cells on the top of the nasal cavity. When airflow brings odor particles to the mucous membrane of the olfactory area, it will stimulate the olfactory cells and produce the sense of smell. When there is inflammation in the nasal cavity, the mucous membrane of the nasal cavity will swell and the mucous membrane of the olfactory area will also swell, and the airflow through the nasal cavity will be weakened, which will affect the sense of smell, so when the cold is serious, we will have the feeling of “deaf nose”. 3.Filtering and cleaning function. The nasal cavity can clean and filter the inhaled air, through the oscillation of the cilia on the surface of the nasal mucosa, to achieve the effect of “dust removal”, so that the air entering the lungs becomes clean. 4.Heating and humidifying function. In winter or cold season, the nose can warm up the cold air and humidify the dry air. 5.Resonance function. Sound from the throat through the nasal cavity, the acoustic flow in the nasal cavity hitting back, producing a resonant effect, so that the sound becomes moist and bright. Once the nasal congestion, this resonance effect will be weakened, so rhinitis or cold, the sound will become “buzzing mumbling”. 6, reduce the weight of the head, protect the head. Because the nasal cavity is cavity, the sinuses are also cavity structure, which greatly reduces the weight of the head, and this hollow structure from the mechanics of its resistance to external forces greatly enhanced, just like airbags, can reduce the impact of external impact on the brain. 7.Reflex function. Reflexes of the nose to form the nasal cycle, the nasal cycle has the characteristics of regular changes, a cycle of 2-7 hours apart, the nasal cycle prompted people to repeatedly turn over during sleep, helping to lift physical fatigue. 8, excretion of excess tears. There is a small hole on the inside of the eye leading to the nose, called the nasolacrimal duct, its role is precisely to excrete these tears, under normal circumstances, these tears through the nasolacrimal duct into the nasal cavity, in the form of nasal snot, and when crying, tears will flow into the nasal cavity in large quantities.