The olfactory organ consists of the left and right nasal cavitiesnasal cavityIt is connected to the outside world through the nostrils, with a nasal septum in the middle. The mucosa on the surface of the nasal septum is connected with the mucosa covering the inner wall of the entire nasal cavity.The function of olfactory sense is to make the human body feel different smells.
The olfactory epithelium is surrounded by Schwarzschild cells, which is where the olfactory center is located.The supporting cells of the nasal mucosa surround the Shuerze cells.Schwarzschild's cells belong to bipolar cells and have two cytoplasmic extensions: dendrites and axons.The dendrites are composed of a cylindrical part and mucosal buds with olfactory cilia, which constitute the starting point of olfaction.The dendrites infiltrate into the supporting cells to reach the surface of the nasal mucosa, and the axons pass through the ethmoid plate to the brain.
The inhaled air contains some substances that can cause the sense of smell. These substances pass through the nasal mucosa to reach the epithelial tissue and contact the olfactory cilia;The olfactory cilia stimulate the end of the cytoplasmic extension, the membrane of the mucosal bud, and transmit this olfactory stimulus to the cytoplasm of the Shuelleri cells.Substances that can cause smell must meet the following conditions: easy to volatilize, soluble in water, soluble in oil
At present, the operation of olfaction cannot be explained clearly. The popular saying is that there are some pits in the olfactory cell membrane. When the smell of substances enters any of the pits, the structure of the cell membrane will change. This change is the beginning of olfactory perception.Each olfactory cell contains an olfactory receptor;There are seven types of human olfactory receptors, each responsible for the perception of different smells.
When we stay in the place with special smell for a long time, we will completely adapt to this smell without feeling it. This phenomenon is called olfactory organ adaptation, which is commanded and controlled by the olfactory cells of the nasal mucosa and the central nervous system.
2、 Olfactory ability
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Different people have great differences in the olfactory sensitivity of the same odor substance. Some people even lack the olfactory ability that ordinary people have. We usually call it olfactory blindness.Even for the same person, the olfactory acuity varies greatly under different circumstances.For example, some diseases have a great impact on the sense of smell. Cold and rhinitis can reduce the sensitivity of the sense of smell.The obvious changes of temperature, humidity and air pressure in the environment also have a great impact on the olfactory sensitivity.
Smell is not so easy to classify as other senses. When describing smell, it is still named after the things that produce smell, such as rose fragrance, meat fragrance, putrid smell
When several different odors are mixed and act on the olfactory receptor at the same time, different situations can occur. One is to produce a new odor, the other is to replace or mask another odor, and it may also produce odor neutralization. The mixed odor will not cause olfaction at all.
Taste and smell organs are two entrances for our body to communicate with the external environment.Therefore, they bear certain vigilance tasks.People's keen sense of smell can prevent harmful gases (war poison gas bombs, liquefied petroleum gas...) from entering the body.
In terms of nutrition, people make different responses to different foods according to the analysis activities of the analyzer and the synergistic activities of smell and taste.
In the case of hearing and vision impairment, olfaction as a distance analyzer is of great significance.Blind and deaf mute people use smell just like normal people use sight and hearing. They often recognize things according to smell, understand the surrounding environment, and determine their own direction of action.
