Final answer:
The nurse is assessing the facial nerve (cranial nerve VII) when asking the patient to raise the eyebrows, smile, and show the teeth. The correct answer is option C.
Step-by-step explanation:
When a nurse asks a patient to raise the eyebrows, smile, and show the teeth, they are assessing the functions of the facial nerve (cranial nerve VII). This nerve is responsible for the motor functions of the muscles used for facial expressions. During a neurological exam, testing the facial nerve is crucial as it reveals the nerve's ability to control these muscles.
Motor functions are sometimes readily visible if facial expressions are compromised, but a formal test can provide a clearer assessment of facial nerve integrity. Notably, the motor control of the gag reflex is controlled by the vagus nerve (cranial nerve X), which serves different functions compared to the facial nerve.
The nurse is assessing the patient's cranial nerves by asking them to raise the eyebrows, smile, and show the teeth.