Cranial Nerves

Question 1

The CNS includes (2)

Answer 1

1) Brain (cerebrum, cerebellum, brainstem)
2) Spinal Cord
(structures encased by bone)

Question 2

The PNS includes (3)

Answer 2

1) Cranial nerves (12 pairs)
2) Spinal nerves (31 pairs)
3) Ganglia

Question 3

12 Cranial Nerves

Answer 3

1) Olfactory
2) Optic
3) Occulomotor
4) Trochlear
5) Trigeminal
6) Abducens
7) Facial
8) Vestibulo-cochlear (Acoustic)
9) Glossopharyngeal
10) Vagus
11) (Spinal) Accessory
12) Hypoglossal

Question 4

Cranial Nerves most important for speech (7)

Answer 4

V- Trigeminal
VII - Facial
VIII- Acoustic 
IX - Glossopharyngeal
X - Vagus
XI - (Spinal) Accessory Nerve
XII - Hypoglossal

Mnemonic: “Try For Good A Vibe, Sweet Honey”

Question 5

Cranial Nerve 1 - Olfactory Nerve responsible for…

Answer 5

sense of smell.

Question 6

Cranial Nerve 1 - Olfactory Nerve afferent OR efferent?

Answer 6

afferent (sensory)

Question 7

Cranial Nerve 2 - Optic Nerve responsible for…

Answer 7

vision

Question 8

Cranial Nerve 2 - Optic Nerve afferent OR efferent

Answer 8

afferent (sensory)

Question 9

Cranial Nerve 3 - Occulomotor Nerve responsible for….

Answer 9

innervating extrinsic muscles of the eye
innervating light and accommodation reflexes
(motor movement of the eye)

Question 10

Cranial Nerve 3 - Occulomotor afferent OR efferent?

Answer 10

efferent (motor movement)

Question 11

Cranial Nerve 4 - Trochlear Nerve responsible for…

Answer 11

innervating muscles of the eyes

motor movement

Question 12

Cranial Nerve 4 - Trochlear Nerve afferent OR efferent?

Answer 12

efferent

Question 13

Cranial Nerve 5 - Trigeminal Nerve responsible for…

Answer 13

Sensation for pain, thermal, tactile in the face, forehead, mouth, nose and teeth

Innervating muscles of mastication
o responsible for jaw movement
o jaw deviates to weak side

*important for speech

Question 14

Cranial Nerve 5 - Trigeminal Nerve afferent OR efferent?

Answer 14

Both

Question 15

Cranial Nerve 6 - Abducens Nerve responsible for…

Answer 15

innervating eye movement (outward)

motor movement

Question 16

Cranial Nerve 6 - Abducens Nerve afferent OR efferent?

Answer 16

efferent (motor movement)

Question 17

Cranial Nerve 7 - Facial Nerve responsible for…

Answer 17

Innervating muscles of facial expression and neck muscles
o bilateral innervation to upper muscles of facial expression
o contralateral innervation to lower muscles of facial expression.
o innervates orbicularis oris
o look for facial asymmetry

Sensing taste in the anterior 2/3 of tongue
Sensation for hard and soft palate
Sensation for ears

*important for speech

Question 18

Cranial Nerve 7 - Facial Nerve afferent OR efferent?

Answer 18

Both

Question 19

Cranial Nerve 8 - Acoustic Nerve/Vestibulo-cochlear Nerve responsible for…

Answer 19

sensation: hearing and balance
o Carries auditory signal to primary auditory cortex

*important for speech

Question 20

Cranial Nerve 8 - Acoustic Nerve/Vestibulo-cochlear afferent or efferent?

Answer 20

afferent (sensation)

Question 21

Cranial Nerve 9 - Glossopharyngeal Nerve responsible for…

Answer 21

Sensation of posterior 1/3 of tongue and pharynx (damage affects gag reflex)

Innervating elevation muscles of the larynx and dilation of the pharynx - stylopharyngeus muscle which elevates pharynx during swallowing and speech

*important for speech (gagging and swallowing)

Question 22

Cranial Nerve 9 - Glossopharyngeal Nerve afferent OR efferent?

Answer 22

Both

Question 23

Cranial Nerve 10 - Vagus Nerve responsible for…

Answer 23

Sensation of the pharynx, larynx, trachea

Motor movement of the palate (elevation + depression)
Motor movement of the larynx

• severed/damage to the vagus can cause vocal fold paralysis
• important for speech (70% of speech is voiced)

Question 24

Cranial Nerve 10 - Vagus Nerve afferent or efferent?

Answer 24

Both

Question 25

Cranial Nerve 11 - (Spinal) Accessory Nerve responsible for…

Answer 25

• breathing- innervates sternocleidomastoid and trapezius muscles
• contributes with Vagus fibers to innervation of levator palatini

*important for speech (breathing)

Question 26

Cranial Nerve 11 - (Spinal) Accessory Nerve afferent OR efferent?

Answer 26

Efferent (motor movement)

Question 27

Cranial Nerve 12 - Hypoglossal Nerve responsible for…

Answer 27

innervating intrinsic and extrinsic muscles of the tongue, lowering soft palate, elevating sides of tongue

• important for speech: extrinsic and intrinsic muscles of the tongue (position + shape of the tongue)
• Tongue deviates to weak side on protrusion.

Question 28

Cranial Nerve 12 - Hypoglossal Nerve afferent OR efferent?

Answer 28

Efferent (muscles movement)

Question 29

mnemonic for remembering afferent vs. efferent:

Answer 29

I: Some (sensory)
II: Say (sensory)
III: Money (motor)
IV: Matters (motor)
V: But (Both)
VI: My (Motor)
VII: Brother (Both)
VIII: Says (Sensory)
IX: Big (Both)
X: Brains (Both)
XI: Mater (Motor)
XII: Most (Motor)

Question 30

mnemonic for remembering Cranial Nerves (sorry it is inappropriate)

Answer 30

I: Oh (Olfactory)
II: Oh (Optic)
III: Oh (Occulomotor)
IV: To (Trochlear)
V: Touch (Trigeminal)
VI: And (Abducens)
VII: Feel (Facial)
VIII: A (Auditory [Vestibulo-cochlear])
IX: Girl's (Glossopharyngeal)
X: Vagina (Vagus)
XI: So (Spinal Accessory)
XII: Heavenly (Hypoglossal)

Question 31

3 branches of the Vagus Nerve (Cranial Nerve X):

Answer 31

o Pharyngeal branch – elevates levator palatini closing off VP port and palatoglossus muscle of tongue.
o Superior laryngeal branch – innervates cricothyroid muscles of larynx
o Recurrent laryngeal branch – innervates all other intrinsic laryngeal muscles.