Brain stem and CNs

Question 1

Brain stem: ventral view

Answer 1

CNs that lie medially at brain stem
3, 6, 12 (multiply up by 2)

All of them happen to be motor too (motor=medial)
-other motor is 4 and 11

Question 2

Brain stem: dorsal view

Answer 2

Pineal gland-melatonin production, circadian rhythm
Superior colliculi-conjugate vertical gaze center
Inferior colliculi- auditory

Parinaud syndrome: paralysis of conjugate vertical gaze due to lesion in superior colliculi (pinealoma)
so can’t look up and secrete bHCG
so precocious puberty.

Your eyes are above your ears, and the superior colliculus (visual) is above the interior colliculus (auditory)

Question 3

CN1

Answer 3

Olfactory, sensory only
The only CN without thalamic relay to cortex
(goes straight to limbic, so gets nostalgic with smell)

Question 4

CN2

Answer 4

Sight, sensory only

Question 5

CN3

Answer 5

Oculomotor, motor

Eye movement (if lesioned, down out), 
Pupillary constriction (sphincter pupillae: Edinger-Westphal nucleus, mascarinic receptor)
Accommodation
Eyelid opeing (levator palpebrae)

Question 6

CN4

Answer 6

Trochlear, motor only

Superior oblique

Question 7

CN5

Answer 7

Trigeminal, both
Mastication
Facial sensation (ophthalmic, maxillary, mandibular)
Somatosensation from anterior 2/3 tongue

Question 8

CN6

Answer 8

Abducens, motor

Question 9

CN7

Answer 9

Facial, Both
Facial movement
Taste from anterior 2/3 of tongue
Lacrimation
Salivation (submandibular and sublingual)
Eyelid closing (orbicularis oculi)
Stapedius muscle in ear
(note: nerve courses through the parotid gland, but does not innervate it)

Question 10

CN8

Answer 10

Vestibulocochlear, sensory

Hearing and balance

Question 11

CN9

Answer 11

Glossopharyngeal, Both

Taste and smatosensation from posterior 1/3 of tongue
Swallowing
Salivation (parotid gland)
Monitoring carotid body/sinus chemo and baroreceptor
Stylopharyngeus (elevates pharynx, larynx)

Question 12

CN10

Answer 12

Vagus, both

Taste from epiglottic region
Swallowing
Palate elevation
Midline uvula
Talking
Coughing
Thoracoabdominal viscera
Monitoring aortic arch chemo and baroreceptors.

Question 13

CN11

Answer 13

Accessory, Motor

Head turning, shoulder shrugging (SCM, trapezius)

Question 14

CN12

Answer 14

Hypoglossal, motor

Tongue movement

Question 15

Cranial nerve nuclei location

Answer 15

Located in tegmentum portion of brian stem
Between dorsal and ventral portion

Lateral nuclei- sensory (aLar plate)
-Sulcus limitans
Medial nuclei- motor (basal plate)

Question 16

Cranial nerve nuclei: midbrain

Answer 16

Midbrain: CN 3 and 9
Oculomotor
Glossopharyngeal

Question 17

Cranial nerve nuclei: pons

Answer 17

Pons: CN 5, 6, 7, 8
Trigeminal
Abducent
Facial
Vestibulocochlear

Question 18

Cranial nerve nuclei: medulla

Answer 18

Medulla: CN 9, 10, 12
Glossopharyneal
Vagus
Hypoglossal

So PICA (lateral medulla) gives you horners (10)

Question 19

Cranial nerve nuclei: spinal cord

Answer 19

Spinal cord: CN 11

Accessory

Question 20

Cranial nerve reflexes:

Corneal

Answer 20

Afferent: V1 ophthalmic (nasociliary branch)
Efferent: VII (temporal branch: orbicularis oculi)

Opthalmic of trigeminal
Facial

Question 21

Cranial nerve reflexes:

Lacrimation:

Answer 21

Afferent: V1 (loss of reflex does not preclude emotion tears)
Efferent: VII

Opthalmic of trigeminal
Facial

Question 22

Cranial nerve reflexes:

Jaw jerk

Answer 22

Afferent: V3 (sensory-muscle spindle from masseter)
Efferent: V3 (motor-masseter)

Sensory of trigeminal
Motor of trigeminal

Question 23

Cranial nerve reflexes:

Pupillary

Answer 23

Afferent: II
Efferent: III

Optic
Oculomotor

Question 24

Cranial nerve reflexes:

Gag

Answer 24

Afferent: IX
Efferent: X

Glossopharyngeal
Vagus