Final answer:
The hypoglossal nerve (CN XII) controls the tongue's motor functions, excluding the palatoglossus muscle, which is regulated by the vagus nerve. Its proper function is crucial for speech and swallowing, and damage may lead to deviation of the tongue during clinical examination.
Step-by-step explanation:
The hypoglossal nerve (CN XII) is responsible for the motor control of the muscles of the tongue, with the exception of the palatoglossus muscle, which is under the purview of the vagus nerve. The two sets of muscles, intrinsic and extrinsic, define the tongue's movement and strength. During a clinical examination, the 'stick out your tongue' test evaluates the function of the hypoglossal. A tongue protruding straight out signifies proper nerve function, while deviation to one side could indicate damage to the nerve on that side. Deficits in hypoglossal function can have impacts on speech and swallowing and may signal potential damage to adjacent neurological structures. Thus, the correct option for the student's question would be Option 1: Control of tongue muscles.