Position :- The pharynx is the part of the throat that is behind the mouth and nasal cavity and above the esophagus and the trachea, or the tubes going down to the stomach and the lungs.
The pharynx is an organ found in vertebrates and invertebrates, though the structure is not universally the same across all of those species. In humans the pharynx is part of the digestive system and also of the respiratory system.
Parts of pharynx:-The conducting zone also includes :-
Function of pharynx:- They are following—
(1) to filter
(3) moisten air
(4) conducting the lungs
Sections of pharynx:-The pharynx has three sections:-
— The nasopharynx
— the oropharynx
(1)Nasopharynx:-The upper portion of the pharynx, the nasopharynx, extends from the base of the to the upper surface skull of soft palate. It includes the space between the internal nares and the soft palate and lies above the oral cavity. The adenoid is a part of nasal cavity also known as the pharyngeal tonsils.
The lymphoid tissue structures located in the posterior wall of the nasopharynx.
(2)Oropharynx:-The oropharynx lies behind the oral cavity, extending from the uvula to the level of the hyoid bone.
It opens anteriorly , through the isthmus faucium into the mouth.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. Because both food and air pass through the pharynx, a flap of connective tissue called the epiglottis closes over the glottis when food is swallowed to prevent aspiration. The oropharynx is lined by non-keratinised squamous stratified epithelium.
(3)Laryngopharynx:- The laryngopharynx, also known as hypopharynx. The part of the throat that connects to the esophagus.
It lies inferior to the epiglottis and extends to the location where this common pathway divers into the respiratory and digestive pathways.
At that point, the laryngopharynx is continuous with the esophagus posteriorly. The esophagus conducts food and fluids to the stomach; air enters the larynx anteriorly. During swallowing, food has the “right of way”, and air passage temporarily stops