The nasopharynx contains the three conchae of the nasal cavity. The top of this structure includes the adenoids or “pharyngeal tonsils” This is a lymphoid nodule like the tonsils we have already talked about and contain lymphocytes that have the capacity to destroy pathogens that come in through the nose. These, like the oropharyngeal tonsils, are larger in children and smaller in adults, sometimes disappearing completely in adults. Other structures of the nasopharynx are the uvula (a teardrop-shaped structure hanging from the soft palate) and the soft palate. These structures will move upward during swallowing in order to keep food from entering the nasal cavity during the act of swallowing. There is also the Eustachian tube, which connects the nasopharynx to the middle ear cavity. The oropharynx is used for both air and food passage. The front of it is the boundary of the oral cavity and is referred to as the “fauces,” while the upper border is the nasopharynx. The epithelium anteriorly changes from ciliated pseudostratified columnar epithelium to stratified squamous epithelium. There are two separate sets of tonsils in this area: the palatine tonsils (on either side of the fauces) and the lingual tonsils, located at the base of the tongue. The laryngopharynx is the lowermost aspect of the pharynx and is located behind the larynx. It is used for digestion and respiration. The anterior part (front part) of the laryngopharynx opens into the larynx. The posterior part (back part) opens into the esophagus.
LARYNX The larynx is made from cartilage. It connects the pharynx to the trachea, sending in just the right amount of air per breath. There are several separate cartilaginous structures that make up the larynx. The thyroid cartilage is located in the front (anteriorly); the epiglottis is above the vocal cords, and the cricoid cartilage is below the cords. The thyroid cartilage is the “Adam’s apple” and is more prominent in men. It is the largest cartilage of the larynx. There are three smaller cartilages that are paired. These are the cuneiforms, the corniculates, and the arytenoid cartilages. Figure 96 shows what the structures of the larynx look like:
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