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Nose

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NOSE ANATOMY

The nose is made up two different sections, the part that elongates from the nasal cavity and projects from the face and the cavity which in at its base and allows for the passage of air. The external portion of the nose is created by skin, cartilage, and two supporting nasal bones. The nasal bones create the basic structure and form the bridge of the nose. The pliable cartilage forms the protrusion, and of course the entire visible package is then covered in skin, nerve ending, and a thin layer of muscle.

NOSE STRUCTURE

The anterior section of the nasal septum is created by septal cartilage. Lateral cartilage on either side and alar cartilages form the basic framework around the nasal cavity, creating the nostrils. The framework for the nasal septum is formed by the vomer and perpendicular plate of the ethmoid bone. Septal cartilage then contributes to the framework of the nasal septum, which segregates the nasal cavity in half laterally. Each of these halves is referred to as a nasal fossa.

The nasal fossa expands anteriorly to create the nasal vestibule. The individual nasal fossas each also widens anteriorly through the nostril. The fossas each communicate with the posterior nasopharnyx via the choana, or the internal nares.

The frontal bone and the two nasal bones create the anterior roof of the nasal cavity. The cribriform plate belonging to the ethmoid bone forms the medial portion, and the sphenoid bone forms the posterior section of the nasal roof. The floor of the nasal cavity is created by the palatine and maxillary bones.

Three boney structures jut out along the internal lateral walls of the nasal cavity. These are referred to as the superior, middle, and inferior nasal conchae or turbinates. In between each conchae are the nasal meatuses, or air passages. The conchae are lined with cilia, technically referred to as the pseudostratified ciliated columnar epithelium. The anterior openings of the nasal cavity are lined with the stratified squamous epithelium. Both regions are amply supplied with mucous secreting goblet cells.

NOSE DIAGRAM

The nose
Image: The Nose

NOSE FUNCTIONS

The nasal cavity performs three basic functions. The conchae are covered with nasal epithelium which is designed to warm the air, cleanse the air, and moisten the air as it in inhaled. The significantly vascular nasal epithelium covers a vast area throughout the nasal cavity. While being highly vascular means that it is effective at warming the incoming air, it also creates the hazards of nose bleeds when it dries out and cracks. The vibrissae are the nasal hairs which line the outer edge of nostril and are responsible for the filtering of macro-particles that may enter the airway and cause difficulties concerning the passage of air.


The combination of the cilia and the moist mucous membrane trap potentially dangerous particles such as smoke, pollen, dust, and other common allergens before it enters the lungs.

The sense of smell, as it relates to the respiratory system, is contributed to by the olfactory epithelium which is located in the upper medial portion of the nasal cavity.

The nasal cavity also contributes to vocalization, as part of the process of voice comes from the resonation of sound against the cavity.
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