Nose

Structure on the face that serves as a passageway for air into and out of the lungs and as an organ of smell.


The facial structure that is the main organ of smell and the primary opening into the respiratory system. The supporting bones of the nose, the nasal bones, protrude from the skull. The nose is not actually a part of the skull, but is made up of a number of cartilages that attach to the nasal bones.


The organ of olfaction, which also acts as an air passage that warms, moistens, and filters the air on its way to the lungs. The external nose is a triangular projection in the front of the face that is composed of cartilage and covered with skin. It leads to the nasal cavity {internal nose), which is lined with mucous membrane containing olfactory cells and is divided into two chambers (fossae) by the nasal septum. The lateral wall of each chamber is formed by the three scroll-shaped nasal conchae, below each of which is a groovelike passage (meatus). The ‘paranasal sinuses open into these meatuses.


In the course of respiration, incoming air enters via the nose and is here warmed, moistened, and filtered before entering the lungs. The nose has a protective function, irritant air being expelled by sneezing. It is also the organ of smell.


The projection in the center of the face that is the organ of smell and the entrance to the nasal cavities. The nose is a triangle composed of and bounded by bone and cartilage covered with skin and lined with mucous membrane. Hairs just inside the nostrils block the entrance of dusts and small insects.


The highest section of the respiratory system and the sensory organ responsible for the sense of smell.


The nose serves as an airway that links the nostrils in the front to the nasopharynx (the upper section of the throat) in the back. Comprising cartilage at the front and bone at the rear, the nasal septum separates this passage into dual chambers.


The nasal bridge takes shape through the fusion of two small nasal bones and cartilage. The upper part of the nasal passage is constructed by bones situated at the foundation of the skull. The lateral walls consist of the maxilla (upper jaw), while the floor is composed of the hard palate. Each wall features three conchae, which are delicate, downward-curving bone plates covered with mucous membrane.


Air-filled cavities lined with mucous membrane, known as paranasal sinuses, connect to the nasal passage. In each wall, there is an aperture for the nasolacrimal duct, which carries away tears. Extending into the upper part of the nasal passage are the delicate, hair-like endings of the olfactory nerves, which play a crucial role in the sense of smell.


An essential role of the nose involves filtering, warming, and humidifying the air that’s breathed in before it continues into the broader respiratory system. Near the nostril openings, tiny hairs catch larger dust particles and foreign objects. The finer dust particles are sifted from the inhaled air by the minuscule hair-like projections on the conchae. The mucus on the conchae moves inward, transporting microorganisms and other foreign substances toward the nasopharynx to be swallowed and eliminated through digestion in the stomach.


The sense of smell is facilitated by the olfactory nerve endings in the nose. These endings are triggered when they come into contact with inhaled vapors, and they subsequently send this information to the olfactory bulb in the brain.


 


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