Certified Rehabilitation Registered Nurse (CRRN) Practice Exam

In which phase does the swallowing reflex initiate?

1. Oral preparatory phase

2. Oral phase

3. Pharyngeal phase

4. Esophageal phase

The correct answer is: Pharyngeal phase

The swallowing reflex initiates in the pharyngeal phase. During this phase, the act of swallowing is triggered as the bolus (a soft mass of chewed food) reaches the back of the throat (pharynx). When the bolus is pushed to the oropharynx, sensory receptors detect its presence and send signals to the brainstem, which coordinates the swallowing reflex. This reflex causes several actions including the elevation of the soft palate to close off the nasal passage, the closure of the vocal cords to protect the airway, and contraction of the pharyngeal muscles to propel the bolus down toward the esophagus. In contrast, the oral preparatory phase involves the preparation of food for swallowing, where food is chewed and mixed with saliva. The oral phase follows this and primarily focuses on moving the bolus to the back of the mouth, but the swallowing reflex itself does not initiate until the bolus reaches the pharyngeal phase. Finally, the esophageal phase consists of the movement of the bolus down the esophagus, where the swallowing reflex has already been completed. Therefore, the pharyngeal phase is crucial as it signifies the point at which voluntary swallowing transitions to an involuntary reflex action that