Functional Components Of The Cranical Nerves

Question 1

What type of sensations do the Cranial Nerves have? (Sensory, motor or both)

Answer 1

1. S Some
2. S Say
3. M Marry
4. M Money
5. B But
6. M My
7. B brother
8. S Says
9. B Bad
10. B Business
11. M Marry
12. M Money

( Some Say Marry Money But My Brother Says Bad Business Marry Money)

Question 2

What does each division of trigeminal function as? (S/M/B)

Answer 2

V1 and V2 are only sensory

V3 is both Sensory and Motor

Question 3

What are the most complex CN’s having motor, sensory, parasympathetic and taste functions?

Answer 3

Facial (CN VII)
Glossopharyngeal (IX)
Vagus (X)

Question 4

Where are the cranial motor nuclei found?

Answer 4

In the brainstem in a rosarla-caudal order

Question 5

The nucleus ambiguous contains LMNs or what CN?

Answer 5

CN IX and X

Question 6

What is the cranial motor nuclei for CN IX and X?

Answer 6

Nucleus ambiguous

Question 7

What CN’s do not receive input from the motor homunculus due to requirement of highly coordinated bilateral movements?

Answer 7

Nucleus of CN III, IV, and VI

Question 8

In what nucleus’s do the cortico-bulbar zones not synapse?

Answer 8

In the nucleus of CN III, IV and VI

Question 9

What do the Trochlear and the abducens nerves innervate?

Answer 9

Lateral Rectus (6)

Superior Oblique (4)

Question 10

What does the spinal accessory nerve (CNXI) innervate?

Answer 10

Only the trapezius and sternocleidomastoid muscles

Question 11

Where are the cell bodies of the LMNs located for CN XI?

Answer 11

In the upper 4-5 cervical levels of the spinal cord and are therefore activated via the cortico-spinal pathway

Question 12

What is the response in an UMN Lesion?

Answer 12

1. Damage to the axons of UMNs prior to the decussation results in paralysis of the associated muscles on the contralateral side.
2. If the injury is to the spinal cord, the paralysis will be on the ipsilateral side. There is an increasing spasticity (rigidity) and no regeneration.

Question 13

What does damage to LMN cause?

Answer 13

Results in ipsilateral flaccidity (loss of tone), weakness, but regeneration is possible

Question 14

Why is the brainstem considered the housekeeping center?

Answer 14

It’s neuronal circuits regulate many autonomic functions

Question 15

What cranial nuclei are in the midbrain?

Answer 15

CN III and IV

Question 16

What cranial nuclei are in the pons?

Answer 16

Nuclei for V and VI

Question 17

What CN nuclei are in the medulla oblongata?

Answer 17

CNS VII, IX, X and XII

Question 18

Where are the nuclei for CN XI?

Answer 18

In lamina IX in the upper cervical spinal cord

Question 19

Where do pain second order neurons synapse? (Periphery)

Answer 19

In lamina I/II about the level of entry into the spinal cord.

They decussate and ascend in the lateral spino-thalamic tract to synapse in the VPL of the thalamus

Question 20

Where do 2nd order neurons for touch go when they enter the spinal cord?

Answer 20

Ascend in the dorsal columns to synapse on 2nd order neurons in either the nucleus gracilis or cuneatus in the brainstem. They decussate forming the medial lemniscus and ascend to synapse on 3rd order neurons in the VPL. 3rd order go to cortex.

Question 21

What are the characteristics of 1st order neurons for pain and touch? (PNS)

Answer 21

1. Their cell bodies reside in afferent ganglia outside the CNS
2. There are no synapses in afferent ganglia
3. The neurons are modality specific

Question 22

What predominates the sensory information from the orofacial region?

Answer 22

The three branches of the trigeminal nerve

Question 23

Where is the cell body for 1st order neurons of the trigeminal system?

Answer 23

The trigeminal ganglion

Question 24

Where do the axons that exit the skulls from the trigeminal terminate?

Answer 24

In the skin of the face in front of the tragal line

Question 25

2nd order neurons for orofacial pain travel in what tract?

Answer 25

The spinal tract

Question 26

Where is the cell body of 2nd order neurons for touch from the orofacial region?

Answer 26

The pontine nucleus

Question 27

Where is the cell body of 2nd order neurons for pain from the orofacial region?

Answer 27

Spinal nucleus

Question 28

2nd order axons for pain and touch from the orofacial region decussate and synapse on what part of the thalamus with the 3rd order neurons?

Answer 28

The VPM of the thalamus Note: CN's go to VPM and spinal nerves to VPL

Question 29

Parasympathetics and sympathetic are ____ only.

Answer 29

Motor

Question 30

Input from what location drives the para/sympathetic?

Answer 30

Hypothalamus

Question 31

What do the postganglionics of the para ANS release?

Answer 31

Acetylcholine

Question 32

What do the sympathetic of the ANS release in post ganglionic neurons?

Answer 32

Nor-adrenaline (norepinephrine)

Question 33

What facial structures receive only sympathetic innervation?

Answer 33

Dilator muscle of iris Superior tarsal muscle Blood vessels

Question 34

What facial structures receive only parasympathetic innervation?

Answer 34

Sphincter and ciliary muscles of the iris

Question 35

Where is the cell body for the sympathetic of the face?

Answer 35

The cell bodies of pre-ganglionic neurons reside in lamina VII (aka the intermediolateral horn) at T1-T2

Question 36

Where do pre-ganglionic neurons for the sympathetic spirit synapse when they are headed to the head?

Answer 36

Superior cervical ganglion

Question 37

Why is it important not to damage blood vessels during surgery of the head region?

Answer 37

Post-ganglionic axons of the ANS (sympathetic) follow blood vessels to their targets

Question 38

How can disruption of the sympathetic supply occur?

Answer 38

Compression of cervical or thoracic sympathetic chain on affected side. A (pancoast) tumor on the apex of the lung

Question 39

What are the symptoms of Horner's syndrome?

Answer 39

(EF'ing PAM) Enopthalmos Flushing of the face due to dilation of blood vessels Pseudoptosis Anhidrosis Miosis

Question 40

What muscle causes pseudoptosis in Horner's?

Answer 40

Paralysis of the superior tarsal muscle

Question 41

What muscle causes Miosis in Horner's?

Answer 41

Inactivation of the dilator muscle

Question 42

What muscle causes enopthalmos in Horner's?

Answer 42

Inactivation of the Mueller muscle

Question 43

What nerves are associated with parasympathetics?

Answer 43

III, VII, IX, X

Question 44

Where do the parasympathetics that travel with cranial nerve 3 originate and synapse? What muscle does this regulate?

Answer 44

O: Nucleus of Edinger-Westphal S: ciliary ganglion M: sphincter muscle

Question 45

Where do the parasympathetics that travel with cranial nerve VII originate and synapse? What does it innervate?

Answer 45

O: Superior salivary nucleus S: 2 different ganglia (to learn later) I: lacrimal, submandibular and sublingual salivary glands

Question 46

Where do the parasympathetics that travel with cranial nerve IX originate and synapse? What does it innervate?

Answer 46

O: inferior salivary nucleus S: otic ganglion I: parotid gland

Question 47

What accounts for activation of all 3 salivary glands in the face?

Answer 47

The inferior and superior salivatory nuclei

Question 48

Where do the parasympathetics that travel with cranial nerve X originate and Innervate?

Answer 48

O: dorsal motor nucleus I: viscera in the thorax and part of the abdomen

Question 49

What are exits of the cranial nerves?

Answer 49

``` Cribiform plate- I Optic Canal - II Superior orbital fissure - 3,4,V1,6 Foramen rotunda - V2 Foramen ovale - V3 Internal acoustic meatus - 7,8 Jugular foramen - 9,10,11 Hypoglossal canal - 12 ```

Question 50

What houses the lower motor nucleus for vagus and glossopharyngeal nerves?

Answer 50

The nucleus ambiguous

Question 51

What tract do UMN's of the CN's travel in beside CN XI?

Answer 51

Cortico-bulbar tract

Question 52

What muscles does the occulomotor nerve innervate?

Answer 52

Levator palpebrae sup. Inferior oblique Sup., inf. And medial rectus

Question 53

What muscles does V3 innervate?

Answer 53

``` Masseter Medial and lateral pterygoid Ant. Belly of digastric Temporalis Tensor tympani Tensor palatini Mylohyoid ```

Question 54

What does the Abducens nerve innervate?

Answer 54

Lateral rectus

Question 55

What does the facial nerves Innervate (muscle)

Answer 55

Stylohoid Post. Belly of digastric Muscle of facial expression Stapedius

Question 56

What muscles does the vagus and glossopharyngeal nerves innervate?

Answer 56

Larynx and pharynx muscles Levator palati Stylopharyngeus

Question 57

What muscles does spinal accessory nerve innervate?

Answer 57

Trapezius | Sternocleidomastoid

Question 58

What muscles does the hypoglossal nerve innervate?

Answer 58

Intrinsic muscles of the tongue Hypoglossal Genioglossus Styloglossus

Question 59

What is plasticity?

Answer 59

The ability of the brain to reorganize neurons in order to learn new functions (or relearn)

Question 60

Where are the cell bodies for pain got second order neuron in the face?

Answer 60

Nucleus of Spinal tract

Question 61

What constricts blood vessels?

Answer 61

Sympathetic

Question 62

What is the pathway of the sympathetic supply to oro-facial region?

Answer 62

1. The cell bodies of pre-ganglionic neurons reside in lámina VII at T1-T2 2. Their axons exit via the ventral root and enter the sympathetic chain via white rami communicantes 3. The axons course up the sympathetic chain to the superior cervical ganglion where they synapse on the post-ganglionic neurons 4. Postganglionic axons follow blood vessels to their targets

Question 63

What is a sunken eye called?

Answer 63

Enophthalmos

Question 64

What are the neurons with parasympathetic function?

Answer 64

III oculomotor VII facial IX Glossopharyngeal X vagus