In fact, this organ is paired, that is, there are two nasal cavities. They are separated from each other by the nasal septum. On the front, each opens the nostril, and on the back it is connected with the nasopharynx with special holes. However, it so happened that these two departments are combined in a speech under the name “nasal cavity”.
Its structure is more complicated than it seems to an ignorant person. The walls of the nasal cavities, the bottom and the roof of the cavity are rigid due to the bone, cartilage and connective tissue of high density. It is because of this structural feature that the cavity does not subside when inhaled.
Each nasal cavity is divided into two parts: the vestibule is an enlarged area directly behind the nostrils, the respiratory cavity is the narrowed part located immediately behind the vestibule. The epidermis, which lines the cavity from the inside, contains a lot of hair follicles, as well as sweat and sebaceous glands. Why exactly is the nasal cavity lined? Its functions are cleansing, increasing humidity and air temperature, therefore it is so abundantly humiliated by blood vessels. Hair can trap large particles in the inhaled air.
In anticipation of the stratified squamous epithelium belongs to the non-keratinous type, then it becomes a multi-row cylindrical ciliated, goblet cells begin to appear in it. The epithelium becomes part of the mucosa lining the respiratory part of the nasal cavity.
Own plate of the mucosa here is adjacent to the periosteum or perichondrium, depending on whether this mucous membrane covers the bone or cartilage. The basement membrane that separates the respiratory epithelium from the lamina propria is much thicker than most other types of epithelium.
The epithelial surface is moistened with mucus, which is produced by goblet cells and glands from its own plate of the mucosa. Up to 500 ml of mucus is produced per day. The latter is mixed with particles of dirt and dust that adhere to it, and thanks to the cilia it moves to the oral cavity. Cleansing the nasal cavity in many respects depends on the condition of the cilia, if they suffer from a disease or injury, this process can be severely disturbed.
In some places near the vestibule there are lymphatic follicles that perform an immune function. In the own plate of the nasal mucosa there are a lot of plasma cells and lymphocytes, sometimes granular leukocytes also come across. They “protect the frontiers” of the body, protecting us from intrusions, because the nasal cavity often becomes the gateway to infections.
However, the cavity "works" not only with air, on the upper part of the walls, as well as the roof of the back of each area there are special cells that make up the organ of smell.
There are two olfactory zones, one in each nasal cavity. The mucous there forms a special organ, thanks to which we are able to smell. The peculiarity of this sensory organ is that the bodies of neurons are located there on the surface, which makes them really vulnerable. Therefore, with injuries to the nose or chronic diseases, a person may lose their sense of smell. We lose another about one percent of our sense of smell for every year of our lives, which is why this important feeling is so disturbed in older people.
Along the lateral plate of each cavity, there are three bone plates located one above one, like small shelves. They are slightly curved downward, therefore, they are called nasal concha.
The sinuses (sinuses) that are located in the bone cavities are also associated with the nasal cavity. The largest is in the upper jaw, smaller sinuses - in the frontal, ethmoid and sphenoid bones. They are filled with mucus and sometimes pus with sinusitis. In this case, drugs are prescribed that make the vessels narrow, and sinus patency increases.
The nasal cavity is complicated, because it should protect us, prepare the air for the lungs and carry out the sense of smell.