Cranial Nerves

Question 1

Cranial nerves

Answer 1

• CN I: Olfactory
• CN II: Optic
• CN III: Oculomotor
• CN IV: Trochlear
• CN V: Trigeminal
• CN VI: Abducens
• CN VII: Facial
• CN VIII: Acoustic (Vestibulocochlear)
• CN IX: Glossopharyngeal
• CN X: Vagus
• CN XI: Accessory
• CN XII: Hypoglossal

Question 2

Function occulomotor n

Answer 2

Innervates the levator palpebrae, superior rectus, medial rectus, medial rectus and inferior oblique which collectively perform most eye movements

Also innervates the sphincter pupillae and the muscles of the ciliary body (autonomic)

Question 3

Function trochlear n

Answer 3

Innervates the superior oblique muscle, which depresses, rotates laterally, and intorts the eyeball

Question 4

Function abducens n

Answer 4

Innervates the lateral rectus, which abducts the eye

Question 5

Function trigeminal n

Answer 5

Receives sensation from the face and innervates the muscles of mastication

Question 6

Function facial nerve

Answer 6

Provides motor innervation to the muscles of facial expression, posterior belly of the digastric muscle, and stapedius muscle

Question 7

Function acoustic n

Answer 7

• Senses sound, rotation, and gravity (essential for balance and movement)
• More specifically, the vestibular branch carries impulses for equilibrium and the cochlear branch carries impulses for hearing

Question 8

Function glossopharyngeal n

Answer 8

• Receives taste from the posterior 1/3 of the tongue, provides secretomotor innervation to the parotid gland, and provides motor innervation to the stylopharyngeus
• Some sensation is also relayed to the brain from the palatine tonsils

Question 9

Function vagus n

Answer 9

1. Supplies innervation to most laryngeal and pharyngeal muscles
2. Also provides parasympathetic fibres to nearly all thoracic and abdominal viscera down to the splenic flexure
3. Controls muscles for voice and resonance and the soft palate

Question 10

Function of the accessory n

Answer 10

Controls the sternocleidomastoid and trapezius muscles

Question 11

Function hypoglossal nerve

Answer 11

1. Provides motor innervation to the muscles of the tongue (except for the palatoglossal, which is innervated by the vagus nerve) and other glossal muscles
2. Important for swallowing (bolus formation) and speech articulation