cranial nerves

Question 1

CN I

Answer 1

Olfactory Nerve

Origin/Nucleus Location: olfactory epithelium

Functional Type: sensory

Main Functions: smell

Question 2

CN II

Answer 2

Optic Nerve

Origin/Nucleus Location: retina of eye

Functional Type: sensory

Main Functions: vision

Question 3

CN III

Answer 3

Oculomotor Nerve

Origin/Nucleus Location: midbrain

Functional Type: motor

Main Functions:

• eye movement (innervates inferior oblique and superior rectus, inferior rectus & medial rectus muscles)
• parasympathetic motor fibers to pupillary constrictor (controls pupil size) and ciliary (controls lens shape) muscles

Question 4

CN IV

Answer 4

Trochlear Nerve

Origin/Nucleus Location: midbrain

Functional Type: motor

Main Functions: eye movement (innervates superior oblique muscle)

Question 5

CN V

Answer 5

Trigeminal Nerve

Origin/Nucleus Location: Pons

Functional Type: mixed

Main Functions:
The largest CN, supplies the face - has 3 divisions…
- Opthalmic division (V1): sensory for anterior scalp, upper eyelid and nose
- Maxillary division (V2): sensory for nasal cavity, palate, upper teeth, cheek and eye areas
- Mandibular division (V3): sensory for anterior tongue (except taste buds), lower teeth chin and temporal regions; motor for muscles of mastication

Question 6

CN VI

Answer 6

Abducens Nerve

Origin/Nucleus Location: pons

Functional Type: motor

Main Functions: eye movement (innervates lateral rectus muscle)

Question 7

CN VII

Answer 7

Facial Nerve

Origin/Nucleus Location: pons

Functional Type: mixed

Main Functions:

• somatic motor innervation to muscles of facial expression
• parasympathetic motor innervation to lacrimal and salivary glands (except parotid glands)
• sensory for taste buds on anterior 2/3 of tongue

Question 8

CN VIII

Answer 8

Vestibulocochlear Nerve

Origin/Nucleus Location: medula oblongata & pons

Functional Type: sensory

Main Functions:

• balance (vestibular branch)
• hearing (cochlear branch)

Question 9

CN IX

Answer 9

Glossopharyngeal Nerve

Origin/Nucleus Location: medulla oblongata

Functional Type: mixed

Main Functions:

• sensory for taste & general sensation from posterior 1/3 of tongue and for pharynx
• somatic motor innervation of muscles of swallowing
• parasympathetic motor fibers to parotid glands

Question 10

CN X

Answer 10

Vagus Nerve

Origin/Nucleus Location: medulla oblongata

Functional Type: mixed

Main Functions:

• the only CN to extend beyond the head and neck region
• innervates muscles of swallowing & talking
• parasympathetic motor innervation to organs of the cardiac, respiratory, & digestive systems
• sensory for taste & external ear

Question 11

CN XI

Answer 11

Accessory Nerve

Origin/Nucleus Location: medulla oblongata AND spinal roots C1 - C5 (subscripted 1 and 5)

Functional Type: motor (primarily)

Main Functions: innervates muscles of neck and upper back, including SCM and trapezius

Question 12

CN XII

Answer 12

Hypoglossal Nerve

Origin/Nucleus Location: medulla oblongata

Functional Type: motor (primarily)

Main functions: innervates intrinsic & extrinsic tongue muscles