Cranial Nerves

Question 1

What is the function of the sympathetic nervous system?

Answer 1

“Fright or Flight” – prepares the body for action.

Question 2

Where is all sympathetic outflow located?

Answer 2

Between T1 and L2 spinal segments.

Question 3

Where do the first-order sympathetic neurons end?

Answer 3

In the sympathetic chain (they are short).

Question 4

How do sympathetic nerves reach the head?

Answer 4

They ascend to the stellate ganglion and travel along the internal carotid artery.

Question 5

Which cranial nerves carry parasympathetic outflow?

Answer 5

CN III (Oculomotor), CN VII (Facial), CN IX (Glossopharyngeal), CN X (Vagus).

Question 6

What spinal nerves contribute to parasympathetic outflow?

Answer 6

Pelvic splanchnic nerves from S2–S4.

Question 7

Where do first-order parasympathetic neurons end?

Answer 7

At or near the target organ

Question 8

What sensations are associated with visceral sensory function?

Answer 8

Taste, haemostasis, satiety, and blood pressure.

Question 9

Which cranial nerves have visceral sensory functions?

Answer 9

CN VII (Facial), CN IX (Glossopharyngeal), CN X (Vagus).

Question 10

Where do first-order visceral sensory neurons synapse?

Answer 10

In the central nervous system (CNS).

Question 11

Which cranial nerve is the only one to cross the midline?

Answer 11

Cranial Nerve IV (Trochlear).

Question 12

Where does the olfactory nerve pass through?

Answer 12

The cribriform plate.

Question 13

What are clinical signs of olfactory nerve damage?

Answer 13

Loss of taste and smell, often after a head injury.

Question 14

What is the pathway of the optic nerve?

Answer 14

Optic nerve → Optic canal → Chiasm → Tracts → Radiations → Occipital lobe.

Question 15

What kind of accidents are typical in optic nerve lesions?

Answer 15

Walking/driving accidents – NOT double vision.

Question 16

What is hemianopia?

Answer 16

Loss of half the visual field.

Question 17

What does “homonymous hemianopia” mean?

Answer 17

Visual field loss on the same side in both eyes.

Question 18

What is the macula responsible for?

Answer 18

Central vision.

Question 19

What parasympathetic functions does CN III serve?

Answer 19

Controls pupil constriction and lens accommodation.

Question 20

Which muscles are innervated by CN III?

Answer 20

Levator palpebrae superioris and all extraocular muscles except superior oblique and lateral rectus.

Question 21

What causes ptosis in oculomotor nerve damage?

Answer 21

Loss of function in the levator palpebrae (supplied by CN III and sympathetic fibers).

Question 22

What muscle does CN IV supply?

Answer 22

Superior oblique.

Question 23

What are three unique traits of CN IV?

Answer 23

It crosses the midline, exits dorsally from the brainstem, and is the thinnest nerve with the longest intracranial course.

Question 24

What muscle does CN VI supply?

Answer 24

Lateral rectus (abducts the eye).

Question 25

What clinical sign is associated with CN VI palsy?

Answer 25

False localising sign of raised intracranial pressure.

Question 26

What functions does CN V have?

Answer 26

Sensory to face and motor to muscles of mastication.

Question 27

What are the three divisions of CN V?

Answer 27

V1 (Ophthalmic, sensory), V2 (Maxillary, sensory), V3 (Mandibular, motor and sensory).

Question 28

What are the sensory functions of CN VII?

Answer 28

Taste (anterior 2/3 tongue) and a small area of the ear canal.

Question 29

What are the motor functions of CN VII?

Answer 29

Muscles of facial expression.

Question 30

What parasympathetic functions does CN VII serve?

Answer 30

Lacrimation and salivation (submandibular/sublingual glands).

Question 31

What is the chorda tympani responsible for?

Answer 31

Taste to anterior 2/3 tongue and salivation.

Question 32

Name the five extracranial branches of CN VII.

Answer 32

Temporal, Zygomatic, Buccal, Marginal Mandibular, Cervical.

Question 33

What does CN VIII supply?

Answer 33

Hearing and balance.

Question 34

Where does CN VIII travel anatomically?

Answer 34

Through the internal auditory canal.

Question 35

What are the sensory functions of CN IX?

Answer 35

Ear canal, tympanic membrane, and posterior 1/3 of the tongue.

Question 36

What are the visceral sensory functions of CN IX?

Answer 36

Taste (posterior 1/3 tongue), carotid sinus and body

Question 37

What parasympathetic function does CN IX serve?

Answer 37

Salivation via the parotid gland.

Question 38

What is CN IX anatomical exit point?

Answer 38

Jugular foramen

Question 39

What are the sensory functions of CN X?

Answer 39

Small area of the ear canal and tympanic membrane.

Question 40

What are the motor functions of CN X?

Answer 40

Muscles of speech.

Question 41

What parasympathetic functions does CN X serve?

Answer 41

Innervates heart, lungs, and gut.

Question 42

What muscles are supplied by the spinal accessory nerve?

Answer 42

Sternocleidomastoid and trapezius.

Question 43

Where does CN XI originate and exit?

Answer 43

Originates in spinal cord, ascends through foramen magnum, exits via jugular foramen.

Question 44

What does CN XII supply?

Answer 44

Motor to the tongue.

Question 45

How is CN XII tested?

Answer 45

Stick out the tongue; deviation is toward the side of palsy.

Question 46

Where does CN XII exit?

Answer 46

Hypoglossal canal.

Question 47

Which cranial nerves are considered "bulbar" nerves?

Answer 47

CN IX, X, XII (9, 10, 12).