Pharynx, a 5 inch long conical, fibromuscular cavity within the throat is situated posterior to the nasal and oral cavities and posterior to the larynx. This is why the pharynx can be divided into three regions depending on the position. The three regions are nasopharynx, the oropharynx and the laryngopharynx. Only air passes through the nasopharynx, while both food and air pass into the oropharynx. The laryngopharynx, only permits passage of air going to the lungs.
Thick connective tissues and muscle fibers attach the pharynx to the base of the skull. Moreover, in the walls of the pharynx exist both longitudinal as well as circular muscles. The alternating contractions of these muscles cause the bolus to move from the pharynx into the food pipe or esophagus. The pharynx also houses the tonsils and adenoids. The pharynx plays an important role in our bodies. It plays a role in both the respiratory as well as the digestive system.
Function of the Pharynx
The pharynx is a common passageway for air and food, which is why pharynx has dual role. The pharynx opens into two pathways, one that leads to the esophagus or food passage and the other trachea or air passage.
Pharynx Function in Digestive System
It is in the pharynx that the second phase of swallowing takes place. The moistened food bolus is moved to the back of the mouth by the tongue and pushed into the pharynx. Here muscle contractions (circular muscle constrictions) take place and the swallowing reflex is triggered. Part of the swallowing action takes place as a reflex action, while part of it is under voluntary control. The food bolus is then pushed toward the esophagus, which is a muscular tube. This swallowing reflex prevents the food from entering in the wind pipe or trachea. Moreover, the flap-like epiglottis covers the larynx, so that no food enters the trachea. The contraction of the longitudinal muscles in the walls of the pharynx lifts the walls of the pharynx during swallowing. When we swallow food, the food enters only the food pipe and not the wind pipe. However, if we talk while eating, sometimes some food particles can enter the wind pipe and cause us to choke.
Pharynx Function in Respiratory System
The air inhaled from the nose and mouth is taken to the pharynx, from which it is sent to the trachea or wind pipe. The air is then sent to the lungs. The mucus lining in the walls of the oropharynx can change slightly to adapt both food as well as air, thus, the pharynx is also a part of the respiratory system. Any injury or damage caused to the pharynx is seen to impede breathing.
Other Pharynx Functions
The process by which humans are able to make vocal sounds and speak is called vocalization. When air passes through the pharynx and then into larynx, it causes the vocal cords in the larynx to vibrate, thereby helping in the production of sound, which is used for speech in humans.
Equalizing Air Pressure in Middle Ear
The eustachian tube or auditory tube connects the middle ear to the pharynx, at an opening in the nasopharyngeal region. This opening opens and closes, thereby equalizing air pressure in the middle ear to that of the outside atmosphere, so that sound conduction takes place properly.
The pharynx, with all the major functions it performs, is a crucial part of the body. It coordinates both inspiration and swallowing while eating, with the help of a flap called epiglottis. If this coordination is missing, choking and aspiration can occur, which are fatal conditions. When this pharynx gets infected, we suffer from sore throat conditions like pharyngitis, which is nothing but inflammation of the pharynx. No wonder, we find it so difficult to swallow food with a sore throat!
Disclaimer: This article is for informative purposes only, and should not be used as a replacement for expert medical advice.