The nose is the main organ related to the sense of smell and also serves in breathing and the respiratory system. The nose is located at the centre of the face, in a median position, which constitutes the initial part of the respiratory tract. Involved in the respiratory and olfactory systems, the nose is formed from the bones and cartilage that form the external structure, which is protruding with respect to the front of the face. Within the nose are the fronts of the nasal cavity consisting of two long and winding channels lined with mucosa that open to the outside of the body, into the nostrils.
What is the nose?
The structure of the nose is formed from bone and cartilage: the bony part comprises the nasal bone and maxilla, while the cartilage part is the one that determines the shape of the tip of the nose. The presence of bones and cartilage in the external structure of the nose is clearly distinguishable by examining the back of the nose. Flowing from the tip to the base of the nose, in fact, there is a difference in hardness of the tissue just under the skin, from softer to harder.
There are two nasal passages: their front part opens to the outside of the body through the nostrils, while the rear part communicates with the nasopharynx (i.e. the upper portion of the pharynx) through two openings, known by the name of "choanal". The nasal fossae are covered internally by the pituitary mucosa and divided into two portions: an upper portion (also called olfactory) and a bottom portion (known as respiratory). The respiratory mucosa is characterized by the presence of a vascular network, which allows heating of the air that is inhaled, as well as by the presence of mucus and cilia, which provide humidification and purification of the same inhaled air. On the other hand, the portion of the olfactory mucosa hosts the olfactory cells, the olfactory bulbs and olfactory nerves.
Externally each of the two pits has projections of bone covered with mucous, or lower, middle and upper turbinate. The two nasal cavities are separated by the nasal septum, which is formed by cartilage and bone. The roof of the two nasal cavities consists an ethmoid bone, which separates the nasal cavities from the brain and it is one of the bones that make up the orbit of an eye.
What function does the nose serve?
There are two functions related to the nose: the respiratory and olfactory functions. The nose is a part of the upper respiratory tract: by inhaling, air enters through the nostrils in the nasal cavity, where it is heated, humidified and purified by the action of the mucus and cilia present in the nasal cavities, in order to continue on his way to the lungs. In terms of the olfactory function, the upper wall that covers the two nasal cavities intercepts olfactory signals, which are transmitted to the brain through the bulb and the olfactory nerve.
