pharynx

Meaning: The pharynx is the muscular throat tube behind the nasal and oral cavities. Inhaled air and swallowed food both pass through it. Air continues through the larynx to the trachea, and food continues into the esophagus. It is divided into the nasopharynx, oropharynx, and laryngopharynx. The Eustachian tube opens into the nasopharynx and helps equalize pressure in the middle ear.

On the MCAT: Questions usually trace the path of air or food, or ask about the swallowing reflex. The voluntary phase begins in the mouth. The pharyngeal phase is a reflex coordinated by the medulla. The soft palate rises to close off the nasal cavity, the larynx rises, and the epiglottis folds over the glottis, so the bolus enters the esophagus instead of the airway. You may need to order the air path (nasal cavity → pharynx → larynx → trachea → bronchi) or predict the result when the epiglottis fails to close, which is choking or aspiration.

Common confusion: Students often assign the pharynx to just one system, or mix it up with the larynx. The pharynx belongs to both the respiratory and digestive tracts. The larynx is the voice box, which contains the vocal cords and the glottis. It lies below the pharynx and forms the entrance to the airway.