Final answer:
The sensory stimulation that triggers the gag reflex is carried by the glossopharyngeal nerve, while the motor response is controlled by the vagus nerve.
Step-by-step explanation:
The nerve responsible for carrying the sensory end of the gag reflex is the glossopharyngeal nerve (cranial nerve IX). This nerve conveys general sensations from the pharyngeal walls and certain taste stimuli that can trigger the gag reflex. During an examination, when the tongue depressor contacts the lateral wall of the fauces, the glossopharyngeal nerve relays sensations that should initiate this reflex.
In conjunction with the glossopharyngeal nerve, the vagus nerve (cranial nerve X) provides the motor component for the gag reflex. The vagus nerve is responsible for contracting the muscles in the pharynx, which is part of this reflex mechanism integral to swallowing and speech functions.
The motor control of the gag reflex is carried by the vagus nerve. The vagus nerve is responsible for the contraction of the muscles in the pharynx, which occurs during swallowing and speaking. The sensory input for the gag reflex is primarily mediated through the glossopharyngeal nerve, which relays general sensations from the pharyngeal walls.