Cranial Nerve - Pons Flashcards Preview

DPT704: Neuro Hank > Cranial Nerve - Pons > Flashcards

Flashcards in Cranial Nerve - Pons Deck (89):
1

What two parts is the pons divided into?

1. Tegmentum
2. Basis Pontis

2

Select the proper portion of the Pons:

Dorsal Portion

a. Tegmentum
b. Basis Pontis

a. Tegmentum

3

Select the proper portion of the Pons:

Contains pontine nuclei and crossing pontine fibers running transversely.

a. Tegmentum
b. Basis Pontis

b. Basis Pontis

4

Select the proper portion of the Pons:

Ventral Portion

a. Tegmentum
b. Basis Pontis

b. Basis Pontis

5

Select the proper portion of the Pons:

Contains cranial nuclei and ascending and descending tracts.

a. Tegmentum
b. Basis Pontis

a. Tegmentum

6

Select the proper portion of the Pons:

This region lies just below the forth ventricle.

a. Tegmentum
b. Basis Pontis

a. Tegmentum

7

Select the proper portion of the Pons:

Marked by large fasicles of fibers containing corticospinal, corticobulbar, and corticopointine axons.

a. Tegmentum
b. Basis Pontis

b. Basis Pontis

8

The Basis Pontis contains pontine nuclei and corssing pontine fibers running transversely which make up

middle cerebellar peducle

9

In the Basis Pontis, large fasicles of fibers containing corticospinal, corticobulbar, and corticopointine axons are running in what direction?

caudal

10

What are the 3 cerebellar peduncles

inferior, middle, and superior

11

All 3 cerebral peducles can be seen at what level?

pontine level

12

As a general principle, the cerebellar peduncles allow for

cerebellar afferents to enter (inferior and middle) and exit (superior) the cerebellum.

13

Which Cranial Nerves are associated with the pons?

CNVIII - Vestibularcochlear
CNVII - Facial
CNVI - Abducens
CNV - Trigeminal

14

What is the function of the Cochlear Division of CNVIII Vestibulochochlear Nerve?

relay of auditory information from specialized receptor, the cochlea.

15

Auditory information is distributed (IPSILATERALLY, CONTRALTERALLY, BILATERALLY) through the brain stem and cortical auditory areas.

Auditory information is distributed BILATERALLY through the brain stem and cortical auditory areas.

16

T/F: Unilateral lesions of the CNS auditory structures do not result in unilateral deafness.

True

17

T/F: Damage to the CNVIII or both cochlear nuclei will result in ipsilateral deafness.

True

18

If sensory stems are topographically organized, how is the entire auditory system organized?

tonotopically

19

Specifically what is the ultimate end goal of auditory pathways?

cerebral cortex:
-the superior surface of the superior temporal gyrus (within the lateral sulcus)
-Broadmann's areas 41 and 42
-Pirmary Auditory Cortex
-Transverse Temporal Gyri of Heschl

20

T/F: Much cross-communication takes place in the auditory pathway before arriving at cortex.

True

The bilateral representation is complex and actual relay steps are unclear. It does however support the ability to localize sound to one side.

21

The Cochlear Nerve consists of axons or central processes of neurons containing what information?

bringing afferent information from the inner ear.

22

Where does the Cochlear Nerve enter the brainstem?

cerebellopontine angle

23

Once the Cochlear Nerve enters the brainstem at the cerebellopontine angle, what does it do?

bifurcates to synapse

24

After the Cochlear Nerve enters the brainstem and bifurcates where does it synapse?

in both dorsal and ventral cochlear nuclei

25

Where are the dorsal and ventral cochlear nuclei located?

both are superficial and located in rostral (open) medullar, adjacent to the based of the inferior cerebellar peduncle.

26

What are the seven synapses that occur for the Cochlear Nerve?

1. Dorsal and Ventral Cochlear Nuclei
2. Superior Olivary Nucleus
3. Lateral Lemniscus
4. Nucleus of Inferior colliculus
5. Brachium of inferior colliculus
6. Medial geniculate nucleus
7. Primary auditory cortex

27

What is the pathway for the protective auditory reflex of turning head TO sound?

Inferior Colliculus >
Superior Colliculus >
Tectospinal Tract

28

Which nucleus is important for protection against loud noise?

Superior olivary nucleus

29

What are the two areas which the superior olivary nucleus can dampen noise?

1. Stapes
2. Malleus

30

What cranial nerve does the olivary nucleus use to dampen noise at the stapes?

CNVII Facial

31

What cranial nerve does the olivary nucleus use to dampen noise at the malleus?

CNV Trigeminal

32

What muscle does the superior olivary nucleus project to the CNVII Facial to dampen noise at the stapes?

Stapedius Muscle

33

What muscle does the superior olivary nucleus project to the CNV Trigeminal to dampen noise at the malleus?

Tensor Tymapni Muscle

34

What is Acoustic Neuroma?

Tumor growing in the cerebellopontine angle, usually benign and beginning on the VIII Vestibulocochlear Nerve

35

What affect does the Acoustic Neuroma have on the Vestibular Component of VIII Vestibulochchlear?

irritative lesion; changes in perception of head position - spinning sensation, vertigo

36

What affect does Acousitc Neroma have besides the vestibular component?

Tinnitus (rinning of the ears); irritative lesion.

37

What nerves can Acoustic Neuroma also involve?

CNVII Facial
CNV Trigeminal
CNIX Glossopharyngeal

38

How can antibiotics affect the auditory system?

Antibiotic Toxicity - some antibiotics are toxic to the CNS (penicillin, streptomyocin) When given for ear infections, they can effect CNVIII Vestibulochoclear specifically.

39

Why can antibiotics effect CNVIII vestibulochoclear specifically?

This CN has a "weak" spot in the change from meninges to the connective tissue component of a peripheral nerve.

40

What is the function of CNV Trigeminal?

Mixed nerve for general sensation of the face and head area, as well as motor output to the muscles of mastication.

41

The sensory parts of CNV Trigeminal carry the same modalities as those carried in

both the dorsal column medial lemniscal and spinothalamic tract.

42

CNV Trigeminal carries general somatosensation for

anterior 2/3 of face

43

CNV Trigeminal is broken up into what divisions?

V1 - Opthalmic Division
V2 - Maxillary Division
V3 - Mandibular Division

44

CNV Trigeminal V1 - Opthalmic Division is responsible for somatosensation

above the eye

45

CNV Trigeminal V2 - Maxillar Division is responsible for somatosensation

below the eye, above the mouth

46

CNV Trigeminal V1 - Mandibular Division is responsible for somatosensation

jaw

47

Lower motor neurons of CNV Trigeminal innervate

muscles of mastication and a couple of other muscles:
-Nerve to Mylohyoid (mylohyoid muscle and the anterior belly of the digastric muscle)
-Tensor Tympani

48

Muscles of mastication are restricted to which division(s) of CNV Trigeminal?

Mandibular Division of CNV

49

Where do the axons for CNV Trigeminal motor division synapse in the middle pons?

Motor Trigeminal Nucleus (CNV)

50

What are the components of the CNVII Facial?

Sensory
Somatic Motor
Autonomic Motor

51

What is the function of the Sensory component of CNVII Facial?

Taste anterior 2/3 of tongue

52

What is the function of the Somatic Motor component of CNVII Facial?

Muscle Expression
and
Reflexive control of auditory sounds - Stapedius

53

What is the function of the Autonomic Motor component of CNVII Facial?

Lacrimal Gland
Submandibular Gland
Sublingual Glands

54

LMN in motor nucleus of VII innervate (IPSILATERAL, CONTRALTERAL, BILATERAL) muscles of facial expression.

LMN in motor nucleus of VII innervate IPSILATERAL muscles of facial expression.

55

What muscles of facial expression do LMN in motor nucleus of VII innervate ipsilatteraly?

Platysma and Stapedius

56

Where do LMN in motor of nucleus VIII exit?

anterolateral part of tegmentum of lower pons

57

CNVII Facial motor neurons in motor nucleus are for muscle on

half of face

(somatotopic organisation)

58

CNVII Facial UMN innervation (corticobulbar) is (IPSILATERAL, CONTRALTERAL, BILATERAL) to upper part of face representation.

UMN innervation (corticobulbar) is BILATERAL) to upper part of face representation.

59

CNVII Facial UMN innervation (corticobulbar) is (IPSILATERAL, CONTRALTERAL, BILATERAL) to lower part of face representation.

UMN innervation (corticobulbar) is CONTRALTERAL to lower part of face representation.

60

A lesion of the nucleus or the fibers of CNVII Facial LMN results in

LMN signs in the innervated muscle as motor neurons are final common pathway.

61

What are the signs of LMN lesions and are the signs ipsilateral or contralateral?

-Flaccid paralysis (atonia or hypotonia)
-Areflexia or hyporeflexia
-Atrophy of muscle (muscle wasting)
-Fasciculations and fibrillations

Signs should be ipsilateral because LMN in motor nucleus of VII innervate ipsilateral muscles of facial expression

62

Where are CNVII Facial preganglionic parasympathetic neurons located?

reticular formation in the caudal pons

63

What are CNVII Facial preganglionic parasympathetic neurons responsible for?

1. Tear Production
2. Salivation

64

Where are CNVII Facial postganglionic cell bodies located for tear production?

pterygopalatine ganglion (lacrimal gland)

65

Where are CNVII Facial postganglionic cell bodies located for salivation?

submandibular ganglia (submandibular and sublingual glands)

66

What branch of the CNVII facial nerve is responsible for taste from anterior 2/3 of tongue?

chorda tympani

67

Through what tract do CNVII Facial Nerve Chorda Tympani run through?

Rostral part of Solitary Nucleus (NTS)

68

What synapses in the caudal part of NTS?

cardio-respiratory and gastrointestinal processes

69

Where does CNVII Facial Nerve Chorda Tympani project to from NTS?

VPM

70

CNVII Facial Nerve Chorda Tympani projects from NTS (IPSILATERALLY, CONTRALATERALLY, BILATERALLY) to VMP.

CNVII Facial Nerve Chorda Tympani projects from NTS IPSILATERALLY to VMP.

71

CNVII Facial Nerve Chorda Tympani projects from NTS ipsilaterally to VMP to ___

gustatory area of cortex - parietal lobe and insula

72

What is Bell's Palsy?

CNVII Facial Nerve LMN deficit to muscles of facial expression.

73

CNVII Facial Nerve UMN lesions - deficit on (IPSILATERAL, CONTRALATERAL, BILATERALLY) lower face.

contralateral lower face only

74

Why is CNVII Facial Nerve UMN lesions deficit on contralteral lower face only?

UMN innervation (corticobulbar) is contralateral only to lower part of face representation.

75

What are symptoms of lesions for LMN deficit for CNVII Facial Nerve?

ipsilateral face
-Dry cornea; ulcerated cornea.
-Loss of taste over ipsilateral ant. 2/3 of tongue.
-Inability to produce saliva.
-Hyperacusis - stapedius can't dampen sound.

-Only lower motor deficit of muscles of facial expression (Bell's Palsy.)

76

What cranial nerves is Corneal Blink Reflex carried by?

CNV Trigeminal
CNVII Facial Nerve

77

What is the Blink Reflex?

courch the cornea and both eyes close

78

What is the Direct Reflex of blink reflex?

closure of touched eye (ipsilateral)

79

What is the Indirect or consensual response of blink reflex?

closure of untouched eye (contralteral)

80

Circuits of Blink Reflex: what is the receptor and what is its peripheral process CN?

free nerve ending in cornea (peripheral process of sensory neuron in the opthalmic division of CNV Trigeminal - elicit with cotton wisp)

81

Circuits of Blink Reflex: where does the afferent limb, opthalmic division of CNV Trigeminal, central process end?

Main Sensory Nucleus of V Trigeminal

82

Circuits of Blink Reflex: interneurons in Main sensory Nucleus of V project directly to ____ and ___.

interneurons in main sensory nucleus of V project directly to IPSILATERAL facial motor nucleus and to RF interneurons.

83

Circuits of Blink Reflex: the Direct Reflex efferent limb runs from ___ to ___

ipsilateral facial motor nucleus to orbicularis oculi - BLINK

84

Circuits of Blink Reflex: the Indirect Reflex efferent limb runs from ____ to ____

RF internerons project to contralateral facial motor nucleus to activate contralateral orbicularis oculi - BLINK

85

If the ipsilateral afferent limb, Opthalmic Division of CNV Trigeminal, from the Sensory Receptor to Main Sensory Nucleus V Trigeminal is cut, what will the result be?

No blink either side.

86

If the efferent limb from ipsilateral Facial Motor Nucleus VII to Orbicularis Oculi is cut, what will the result be?

Loss of direct response, ipsilateral facial paralysis

87

If the efferent limb from Main Sensory Nucleus V Trigeminal to ipsilateral Facial Motor Nucleus VII is cut, what will the result be?

Loss of direct response, no evidence of facial paralysis

88

If the RF interneuron from Main Sensory Nucleus V Trigeminal to contralateral Facial Motor Nucleus VII, what will the result be?

Loss of indirect response, no evidence of facial paralysis.

89

If the efferent limb from contralateral Facial Motor Nucleus VII to orbicularis oculi is cut, what will the result be?

Loss of indirect response, contralateral facial paralysis