Which phase of swallowing involves voluntary control and the action of cranial nerves #5 and #7?

Which phase of swallowing involves voluntary control and the action of cranial nerves #5 and #7?

• A. Pharyngeal Phase
• B. Oral Phase
• C. Esophageal Phase
• D. Digestive Phase

Answer: (B)

The oral phase of swallowing is characterized by its voluntary nature, during which a person consciously decides to chew food and push the bolus towards the back of the mouth to initiate swallowing. This phase involves a coordinated action of several cranial nerves, particularly cranial nerves #5 (trigeminal nerve), which is responsible for the sensation in the face and motor functions such as biting and chewing, and #7 (facial nerve), which plays a critical role in controlling the muscles of facial expression and helps with the movements necessary for manipulating food in the mouth. In contrast, the pharyngeal phase is primarily involuntary, focusing on the reflexive action to propel the bolus through the pharynx, while the esophageal phase further follows as a series of involuntary muscle contractions that move the bolus down the esophagus into the stomach. The digestive phase is not a recognized phase of swallowing in this context, as it refers more broadly to the process of digestion after swallowing has already occurred. Thus, the correct answer highlights the specific characteristics and neural control involved in the oral phase.

The oral phase of swallowing is characterized by its voluntary nature, during which a person consciously decides to chew food and push the bolus towards the back of the mouth to initiate swallowing. This phase involves a coordinated action of several cranial nerves, particularly cranial nerves #5 (trigeminal nerve), which is responsible for the sensation in the face and motor functions such as biting and chewing, and #7 (facial nerve), which plays a critical role in controlling the muscles of facial expression and helps with the movements necessary for manipulating food in the mouth.

In contrast, the pharyngeal phase is primarily involuntary, focusing on the reflexive action to propel the bolus through the pharynx, while the esophageal phase further follows as a series of involuntary muscle contractions that move the bolus down the esophagus into the stomach. The digestive phase is not a recognized phase of swallowing in this context, as it refers more broadly to the process of digestion after swallowing has already occurred. Thus, the correct answer highlights the specific characteristics and neural control involved in the oral phase.