Lab 2 - Cranial Nerves

Question 1

Olfactory

Answer 1

CN I
sensory: smell
Motor: none
Synapse in olfactory bulbs

Question 2

Optic

Answer 2

CN II
Sensory: vision
Motor: none
Optic chiasma, optic tracts, synapse in thalamus, sent to visual cortex

Question 3

Occulomotor

Answer 3

CN III
sensory: none*
Somatic motor: 4 extrinsic eye muscles (directing eye), elevates eyelid
Autonomic motor: constricts pupil, focuses eye
Fibers from ventral midbrain to eye muscles

Question 4

Trochlear

Answer 4

CN IV
Sensory: none
Somatic motor: superior oblique eye muscle (down and out movement)
Autonomic motor: none
Fibers extend from dorsal midbrain through superior orbital fissures to Innervate superior oblique muscle

Question 5

Trigeminal

Answer 5

CN V
Sensory: touch, pain, temperature from face, mouth, ear
Somatic motor: muscles of mastication, mylohyoid, middle ear muscles
No autonomic motor
Extends from pons to face

*has ophthalmic division (forehead), maxillary (cheek), mandibular division (jaw muscles, only motor branch)

Question 6

Abducens

Answer 6

CN VI
Sensory: none
Somatic motor: lateral rectus muscle (moves eye out)
Autonomic motor: none
Fibers from inferior pons enter orbits via superior orbital fissures

Question 7

Facial

Answer 7

CN VII
Sensory: taste for front of tongue
Somatic motor: muscles of facial expression, digastric, stylohyoid, middle ear muscles
Autonomic motor: makes tears and saliva
Fibers from pons travel through internal acoustic meatuses

Question 8

Vestibulocochlear

Answer 8

CN VIII
Sensory: hearing (cochlear) and balance (vestibular)
Motor: none except tiny adjustment neurons in inner ear
Enter brainstem at Pons medulla border through internal auditory meatus

Question 9

Glossopharyngeal

Answer 9

CN IX
Sensory: taste (back of tongue)
Somatic motor: pharyngeal muscle (stylopharyngeus) (swallowing)
Autonomic motor: makes saliva
Fibers leave medulla through jugular foramen

Question 10

Vagus

Answer 10

CN X
Sensory: visceral sensory of organs, somatic sensory of ear canal, ear drum, throat
Somatic motor: most larynx and pharynx muscles
Autonomic motor: GI tract smooth muscle and glands, decreases heart rate and air flow

Question 11

Accessory

Answer 11

CN XI
No sensory function or autonomic motor
Somatic motor: trapezius and sternocleidomastoid

Question 12

Hypoglossal

Answer 12

CN XII
No sensory or autonomic motor function
Somatic motor: intrinsic and extrinsic tongue muscles