Book : Human Anatomy
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Posted by: CHELSEA
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Writer CHELSEA

Pharynx

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Overview:

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 (behind the nasal cavities), the oropharynx (behind the buccal cavity) and the laryngopharynx (behind the larynx). Only air passes from the nose through the nasopharynx, while both food and air pass from the mouth into the oropharynx. The third section, that is the laryngopharynx, once again 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 plays an important role in our bodies. It plays a role in both the respiratory as well as the digestive system.

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 extending from the esophagus. This swallowing reflex prevents the food from entering in the wind pipe or 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. 



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