Cranial Nerves 1

Question 1

What do special visceral efferents supply?

Answer 1

Muscles derived from pharyngeal arches

e.g. muscles of mastication, face, larynx, pharynx

Question 2

What do special visceral afferents recieve?

Answer 2

Olfaction, gustation

Question 3

What do special somatic afferents recieve?

Answer 3

Vision, hearing, balance

Question 4

What do general somatic efferents supply?

Answer 4

Striated voluntary muscles in head and neck

Question 5

What do general visceral efferents supply?

Answer 5

Parasympathetic secretomotor from to viscera, blood vessels and glands

Question 6

What do general somatic afferents recieve?

Answer 6

Pain, touch and temperature from head and neck

Question 7

What do general visceral afferents recieve?

Answer 7

Sensation from viscera, blood vessels and glands

Question 8

What structures does CN III supply?

Answer 8

Levator palpebrae superioris
Superior, inferior and medial recti
Inferior oblique
Parasympathetics to pupil for constriction
Sympathetics to levator palpebrae superioris (smooth muscle)

Question 9

Why may CN III, IV and VI become compressed in raised ICP?

Answer 9

CN III and IV are closely related to the tentorium cerebelli

CN VI passes upwards on the clivus

Question 10

Why may CN III become compressed by aneurysms in the circle of Willis?

Answer 10

Passes between the posterior cerebral and superior cerebellar arteries before lying close to the posterior communicating artery

Question 11

Where is the superior orbital fissure located?

Answer 11

Between the greater and lesser wings of the sphenoid

Question 12

How would a CN III palsy present?

Answer 12

Eyes turned down and out
Ptosis
Pupillary dilation

Question 13

What muscle does CN IV supply?

Answer 13

Superior oblique

Question 14

What muscle does CN VI supply?

Answer 14

Lateral rectus

Question 15

What is the effect of the SNS on the eye?

Answer 15

Supplies smooth muscle component of levator palpebrae superioris that keeps the eye open
Pupil dilation via long ciliary nerve (from nasociliary nerve)

Question 16

What is the effect of the PNS on the eye?

Answer 16

Pupil constriction and lens accommodation via short ciliary nerve

Question 17

Which fibres synapse in the ciliary ganglion?

Answer 17

Preganglionic parasympathetic fibres from the Edinger-Westphal nucleus

Question 18

Describe the route of sympathetic information from the trunks to the eye

Answer 18

• -> Superior cervical ganglion
• -> Carotid plexus
• -> Nasociliary nerve, occulomotor nerve and ciliary ganglion (pass through)

Question 19

Which nerve carries sympathetic fibres to the eye that cause pupillary dilation?

Answer 19

Nasociliary then long ciliary nerve

Question 20

What cranial nerve is the nasociliary nerve a branch of?

Answer 20

Ophthalmic division (CN V1) of the trigeminal nerve (CN V)

Question 21

Where does CN V1 give off the nasociliary nerve?

Answer 21

Just after it passes the cavernous sinus

Question 22

What are the 4 features of Horner’s syndrome?

Answer 22

Miosis
Ptosis
Anhydrosis
Flushed face

Question 23

Name the afferent modalities

Answer 23

Special somatic
General somatic
Special visceral
General visceral

Question 24

Name the efferent modalities

Answer 24

General somatic
Special visceral
General visceral

Question 25

Which modalities are on the alar plate?

Answer 25

Sensory

Question 26

Which modalities are on the basal plate?

Answer 26

Motor

Question 27

How do post-ganglionic PNS fibres from the ciliary ganglion reach the eye?

Answer 27

Short ciliary nerve