The floor of the nasal cavity is composed of the hard palate and the soft palate. The conchae and meatuses trap water during exhalation preventing dehydration. Conchae increase the surface area of the nasal cavity, disrupting the flow of air as it enters the nose and causing air to bounce along the epithelium, where it is cleaned and warmed. The nasal septum is formed anteriorly by a portion of the septal cartilage and posteriorly by the perpendicular plate of the ethmoid bone and the thin vomer bones.Įach lateral wall of the nasal cavity has three bony projections: t he inferior conchae are separate bones, and t he superior and middle conchae are portions of the ethmoid bone. The nares open into the nasal cavity, which is separated into left and right sections by the nasal septum ( Figure 12.2). When discussing the nose, it is helpful to divide it into two major sections:
The major entrance and exit for the respiratory system is through the nose. The oropharynx is a passageway for both air and food.Anatomy (Structures) of the Respiratory System The Nose and its Adjacent Structures This connection is why colds often lead to ear infections. In addition, auditory (Eustachian) tubes that connect to each middle ear cavity open into the nasopharynx. Both the uvula and soft palate move like a pendulum during swallowing, swinging upward to close off the nasopharynx to prevent ingested materials from entering the nasal cavity. The uvula is a small bulbous, teardrop-shaped structure located at the apex of the soft palate. The pharyngeal tonsils are large in children, but interestingly, tend to regress with age and may even disappear.
The function of the pharyngeal tonsil is not well understood, but it contains a rich supply of lymphocytes and is covered with ciliated epithelium that traps and destroys invading pathogens that enter during inhalation. A pharyngeal tonsil, also called an adenoid, is an aggregate of lymphoid reticular tissue similar to a lymph node that lies at the superior portion of the nasopharynx. At the top of the nasopharynx are the pharyngeal tonsils. The nasopharynx is flanked by the conchae of the nasal cavity, and it serves only as an airway. The pharynx is divided into three regions: the nasopharynx, the oropharynx, and the laryngopharynx.
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