Question

The cranial nerve that regulates the heartbeat is:

• A. IX
• B. VII
• C. X
• D. VIII

Answer 1

The Correct Option is C

The correct option is (C): X.

Answer 2

The question asks which cranial nerve regulates the heartbeat. Let's check each of the numbered cranial nerves listed.

1. IX (glossopharyngeal): This nerve mainly handles taste sensation from the back of the tongue, sensation from the pharynx, and control of the parotid gland and a pharyngeal muscle. It has a small role in monitoring blood pressure through the carotid sinus but does not directly regulate heart rate.
2. VII (facial): This nerve controls the muscles of facial expression, taste in the front two-thirds of the tongue, and some glandular secretions like tears and saliva. It has no role in controlling the heart.
3. X (vagus): The vagus nerve is the main parasympathetic supply to the heart. It slows the heart rate by acting on the sinoatrial node, and it also supplies the lungs and much of the digestive tract. This nerve is directly responsible for regulating heartbeat.
4. VIII (vestibulocochlear): This nerve carries information about hearing and balance from the inner ear to the brain. It is a purely sensory nerve with no connection to heart function.

Of the four cranial nerves listed, only the vagus nerve carries parasympathetic fibers to the heart and directly regulates its rate.

Therefore, the correct answer is X.