Cranial Nerves

Question 1

What forms the sensory portion of the brain stem as it developed from the neural tube ?

Answer 1

The Alar plate, positioned posteriorly, will form the sensory portion of the brain stem

Question 2

What will the motor portion of the brain stem develop from ?

Answer 2

The Basal plate, positioned anteriorly, will form the motor portion of the brain stem.

Question 3

What separates the basal plate from the alar plate?

Answer 3

The sulcus limitans

Question 4

CN-1

Answer 4

Olfactory: More of a tract than a nerve. It carries fibers from the olfactory bulb to the olfactory portion of the cerebral cortex.

Question 5

CN-2

Answer 5

Optic Nerve: Carries visual information from the retina to the optic chasm

Question 6

CN-3

Answer 6

Occulomotor:
1. GSE Nucleus- tegmentum of the rostral midbrain at the level of the superior colliculus. Responsible for all of the eye movements. Except for SO4 LR6

2. GVE nucleus Edinger- Westphal Nucleus which is posterior to the occulomotor nucleus. These fibers are involved in the pupillary light reflex and accommodation

Question 7

CN-4

Answer 7

Trochlear, located in the tegmentum of the mid brain. GSE innervate the contralateral superior oblique. The fibers cross over before exiting caudal to the inferior colliculus.

Question 8

CN-5

Answer 8

Trigeminal- Principle GSA to the head. Provides SVE or BE to the muscles of mastication.

Question 9

mesencephalic nucleus

Answer 9

GSA CN5- Proprioception from the muscles of mastication

Question 10

Chief nucleus

Answer 10

Discriminative touch and vibration from the head.

Question 11

Spinal Nucleus

Answer 11

GSA, pain and temperature from the head.

Question 12

Motor Nucleus

Answer 12

SVE / BE –> Motor to the muscles of mastication

Question 13

CN-6

Answer 13

Abducen Nucleus GSE, motor to the lateral rectus

Question 14

Where does the facial nerve emerge from the brain stem ?

Answer 14

Pontomedullary Junction

Question 15

Facial Nucleus

Answer 15

CN-7 –> SVE / BE –> Motor to the muscles of facial expression.

Question 16

Chief nucleus of CN 5- Hint, not the CN-5 function

Answer 16

GSA –> Sensory from the external acoustic meatus and skin posterior to the ear.

Question 17

Superior Salivary Nucleus

Answer 17

GVE –> Parasympathetic motor to the lacrimal, sublingual, and submandibular glands.

Question 18

Nucleus Solitarius

Answer 18

GVA- Chemoreceptors and barioreceptors in the carotid body, visceral afferent information from the young and pharynx

SVA- Taste from the anterior 2/3 of the tongue

Question 19

What two nuclei does the vestibulococlear nerve synapse in ?

Answer 19

Vestibular nuclear complex and cochlear nuclear complex

Question 20

Vestibular nuclear complex

Answer 20

CN-8 SSA –> Balance

Question 21

Cochlear Nuclear Complex

Answer 21

CN-8 SSA –> Hearing

Question 22

What are the two divisions of the facial nerve ?

Answer 22

1. The facial nerve proper- Motor control to the muscles of facial expression ( SVE & BE )
2. Nervus Intermedius

Question 23

CN-8

Answer 23

Vestibulocochlear

Question 24

What types of fibers does the vestibulocochlear nerve carry ?

Answer 24

Vestibular fibers for balance and Cochlear fibers for hearing.