Which cranial nerves coordinate the swallowing reflex?

The coordination of the swallowing reflex primarily involves the glossopharyngeal nerve (cranial nerve IX) and the vagus nerve (cranial nerve X). The glossopharyngeal nerve plays a crucial role in the sensory aspect of swallowing. It provides sensation to the throat and the back of the tongue, which is essential for triggering the swallowing reflex. When food or liquid is sensed in the pharynx, this nerve activates the appropriate reflex mechanisms.

The vagus nerve, on the other hand, is responsible for motor control during swallowing. It innervates the muscles of the pharynx and larynx, helping to facilitate the movement of food from the mouth into the esophagus and preventing aspiration into the airway. This dual action—sensation from IX and motor control from X—is vital for a smooth and effective swallowing process.

In contrast, the other combinations of cranial nerves, while they may have roles in other functions (like the facial nerve for taste or the accessory nerve for head and shoulder movement), do not primarily coordinate the swallowing reflex. Thus, the pairing of cranial nerves IX and X is fundamental to the swallowing reflex, making this the correct answer.