Parasympathetic preganglionic fibers run in which cranial nerves? (4)

• A. CN III, VII, IX, X
• B. CN II, III, IV, V
• C. CN I, II, III, IV
• D. CN V, VIII, IX, X

Answer: (A)

Parasympathetic preganglionic fibers originate in brainstem autonomic nuclei and travel with four cranial nerves to reach their targets. The nerves carrying these preganglionic fibers are the oculomotor (III), facial (VII), glossopharyngeal (IX), and vagus (X).

The oculomotor nerve sends preganglionic fibers to the ciliary ganglion, regulating pupil constriction and lens accommodation. The facial nerve carries preganglionic fibers to the pterygopalatine and submandibular ganglia, affecting lacrimal and some salivary glands. The glossopharyngeal nerve provides preganglionic input to the otic ganglion, influencing the parotid gland. The vagus nerve supplies the majority of parasympathetic innervation to thoracic and abdominal organs via intramural ganglia.

Other cranial nerves listed do not carry parasympathetic preganglionic fibers in this arrangement, as they are primarily sensory or motor.