Parasympathetic output to the thorax and abdomen is carried by which nerve?

• A. Vagus
• B. Trigeminal
• C. Hypoglossal
• D. Facial

Answer: (A)

Parasympathetic control of the thorax and much of the abdomen travels with the vagus nerve. This cranial nerve carries preganglionic parasympathetic fibers that extend from the brainstem and synapse in ganglia near or within the target organs, providing functions such as slowing the heart, constricting the airways, and increasing GI secretions and motility. The other nerves have different primary roles: the trigeminal nerve is mainly sensory to the face and motor to muscles of mastication (not thoracic/abdominal autonomic output), the hypoglossal nerve controls tongue movements, and the facial nerve mainly supplies parasympathetic output to head and neck glands rather than thoracic or abdominal viscera.