Cranial Nerves

Question 1

Cranial Nerves location

Answer 1

located around brainstem area

Question 2

Brain stem tracts

Answer 2

Long tracts: sensory and motor
Reticular formation: sleep and pain regulation, protection to all areas

Question 3

Cranial Nerves serve…

Answer 3

-areas of the face, cervical spine, provide sensory applications and ANS function for body organs

Question 4

Tract for Cranial Nerves

Answer 4

-Corticobulbar tract
-in primary motor cortex
-decussation in brainstem to synapse w/ motor neurons in nuclei of CN V, VII, IX, CX, XI, XII (but still bilaterally innervate)
-Cranial nerves III, IV, and VI controlled in more complex way

Question 5

Cranial Nerve Names

Answer 5

I: Olfactory (sensory)
II: Optic (sensory)
III: Occulomotor (motor and PSNS)
IV: Trochlear (motor)
V: Trigeminal (sensory and motor)
VI: Abducens (motor)
VII: Facial (motor and PSNS)
VIII: Vestibulocochlear (sensory)
IX: Glosspharyngeal (motor and sensory)
X: Vagus (motor and sensory)
XI: Accessory (motor)
XII: Hypoglossal (motor)

Question 6

Olfactory CN

Answer 6

-CN I
-smell, interacts with memory
-Olfactory bulb and olfactory tract

Question 7

Optic CN

Answer 7

-CN II
-visual information
Retina –> Optic N –> Optic Chiasm

Question 8

Control of ocular muscles by which CN

Answer 8

CN III, CN IV, CN VI
-responsible for coordinated eye mvmt

Question 9

Occulomotor CN

Answer 9

-CN III
-control of 4 optic muscles (Superior rectus, Medial rectus, Inferior oblique, Inferior rectus)
-Responsible for parasympathetic pupil constriction

Question 10

Pupillary reflex

Answer 10

-CN III (parasympathetic function)
-Midbrain delivers pupil movement to response to light or other objects
-Stimulation to one pupil will cause contralateral pupil to response
-DIRECT Response: Constriction in ipsilateral eye
-CONSENSUAL Response: Constriction in contralateral eye
-Loss of direct and consensual response: problem w/ CN II

Question 11

Trochlear CN

Answer 11

-CN IV
-control of 1 ocular muscle: Superior Oblique

Question 12

Abducens CN

Answer 12

-CN VI
-control of 1 ocular muscle: Lateral Rectus (abducts eyeball)
-Pathology: Inability to maintain eye midline, eyes at rest rotate medially, loss of muscle pull (abduction)

Question 13

Trigeminal CN

Answer 13

-CN V
-Three Divisions: V1 (Opthalamic), V2 (Maxillary), V3 (Mandibular)
-Sensation: Face, mouth, teeth, nasal cavity
-Motor: Muscles of Mastication via Anterior trunk of V3 (Masseter, Temporalis)

Question 14

Facial CN

Answer 14

-CN VII
-Motor: Wrinkling forehead, Eye (elevating eyebrow, bringing eyebrows together), Nose (wrinkling nose), Lips (pursing lips, smiling)
-Parasympathetic: Taste in anterior 2/3 of tongue (sublingual salivary glands)

Question 15

Bell’s Palsy (facial nerve lesion) vs Supranuclear lesion (UMN lesion)

Answer 15

Bell’s Palsy: Injury in facial nerve, complete facial paralysis bc R and L input affected
Supranuclear Lesion: UMN lesion, sparing of forehead bc if L side affected, face will still receive input from R side

Question 16

Vestibulocochlear CN

Answer 16

-CN VIII
-two nerves: Vestibular branch (balance) & Cochlear branch (auditory)
-Vestibular branch: Semicircular canals (Rotational Acceleration) & Saccule-Utricle (Acceleration/ Gravity)

Question 17

Glossopharyngeal CN

Answer 17

-CN IX
-Motor: dilates pharynx, parotid salivary gland (visceral motor PSNS)
-Sensory: posterior 1/3 tongue, upper pharynx, carotid sinus (visceral sensory)

Question 18

Vagus CN

Answer 18

-CN X
-Mixed motor and sensory
-PSNS (regulates heart, lungs, intestines, and stomach)
-Test: Laryngeal (gag reflex) “Ahhh”

Question 19

Hypoglossal CN

Answer 19

-CN XII
-runs inferior to tongue
-innervates tongue muscles
-Test: sticking out tongue
*UMN: tongue deviates contralateral to lesion
*LMN: tongue deviates ipsilateral to lesion

Question 20

Accessory CN

Answer 20

-CN XI
-innervation of trapezius and SCM
-descends with vagus