The anterior wall consists of the base of the tongue and the epiglottic vallecula the lateral wall is made up of the tonsil, tonsillar fossa, and tonsillar (faucial) pillars the superior wall consists of the inferior surface of the soft palate and the uvula. It opens anteriorly, through the isthmus faucium, into the mouth, while in its lateral wall, between the palatoglossal arch and the palatopharyngeal arch, is the palatine tonsil. The oropharynx lies behind the oral cavity, extending from the uvula to the level of the hyoid bone. It also contains some muscle fibres called salpingopalatine muscle The tensor veli palatini is lateral to the levator and does not contribute to the fold, since the origin is deep to the cartilaginous opening. the salpingopalatine fold, a smaller fold, in front of the salpingopharyngeal fold, extending from the superior part of the torus to the palate and containing the levator veli palatini muscle.the salpingopharyngeal fold, a vertical fold of mucous membrane extending from the inferior part of the torus and containing the salpingopharyngeus muscle.Two folds arise from the cartilaginous opening: On its lateral wall is the pharyngeal opening of the auditory tube, somewhat triangular in shape and bounded behind by a firm prominence, the torus tubarius or cushion, caused by the medial end of the cartilage of the tube that elevates the mucous membrane. The anterior aspect of the nasopharynx communicates through the choanae with the nasal cavities. The opening and closing of the auditory tubes serves to equalize the barometric pressure in the middle ear with that of the ambient atmosphere. The auditory tube, which connects the middle ear to the pharynx, opens into the nasopharynx at the pharyngeal opening of the auditory tube. Polyps or mucus can obstruct the nasopharynx, as can congestion due to an upper respiratory infection. The nasopharynx is lined by respiratory epithelium that is pseudostratified, columnar, and ciliated. Waldeyer's tonsillar ring is an annular arrangement of lymphoid tissue in both the nasopharynx and oropharynx. The adenoids, also known as the pharyngeal tonsils, are lymphoid tissue structures located in the posterior wall of the nasopharynx. It includes the space between the internal nares and the soft palate and lies above the oral cavity. The upper portion of the pharynx, the nasopharynx, extends from the base of the skull to the upper surface of the soft palate. Structure Nasopharynx Upper respiratory system, with the nasopharynx, oropharynx and laryngopharynx labeled at left They are arranged as an inner layer of longitudinal muscles and an outer circular layer. In humans, two sets of pharyngeal muscles form the pharynx and determine the shape of its lumen. The human pharynx is conventionally divided into three sections: the nasopharynx, oropharynx, and laryngopharynx. (The conducting zone-which also includes the nostrils of the nose, the larynx, trachea, bronchi, and bronchioles-filters, warms and moistens air and conducts it into the lungs). In humans, the pharynx is part of the digestive system and the conducting zone of the respiratory system. The flap of cartilage called the epiglottis stops food from entering the larynx. The pharynx carries food to the esophagus and air to the larynx. It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx ( pl.: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively).
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