Cranial Nerves Flashcards Preview

MD1 Neuroscience > Cranial Nerves > Flashcards

Flashcards in Cranial Nerves Deck (124):
1

What are cranial nerves?

12 paired nerves
Connected to brain

2

What do cranial nerves supply?

Somatic and visceral motor and and sensory info to head
CN IX and X also supply visceral sensory and motor innervation to neck, chest, and abdomen

3

What is cranial nerve I?

Olfactory

4

What is cranial nerve II?

Optic

5

What is cranial nerve III?

Oculomotor

6

What is cranial nerve IV?

Trochlear

7

What is cranial nerve V?

Trigeminal

8

What is cranial nerve VI?

Abducent

9

What is cranial nerve VII?

Facial

10

What is cranial nerve VIII?

Vestibulocochlear

11

What is cranial nerve IX?

Glossopharyngeal

12

What is cranial nerve X?

Vagus

13

What is cranial nerve XI?

Accessory?

14

What is cranial nerve XII?

Hypoglossal

15

Which cranial nerves are purely sensory?

CN I
CN II
CN VIII

16

Which cranial nerves are purely motor?

CN III
CN IV
CN VI
CN XI
CN XII

17

Which cranial nerves are mixed?

CN V
CN VII
CN IX
CN X

18

What are cranial nerves connected centrally to?

Cranial nerve nuclei

19

Which cranial nerves are associated with the brainstem?

CN III to CN XII

20

How are cranial nerves organised?

Rostral to caudal roughly in order of target tissues they're associated with

21

On which surface do cranial nerves exit?

All exit ventrally
Except CN IV - exits dorsally

22

Which cranial nerve crosses over before leaving the brain?

CN IV

23

From where do motor nerves exit?

Located medially
Exit close to midline

24

How are the motor nerve nuclei organised?

In 3 columns close to midline

25

What are the three motor nerve nuclei columns, from medial to lateral?

Somatic
Branchial
Visceral

26

Which nerves have somatic motor fibres?

CN III
CN IV
CN VI
CN XII

27

Which nerves have branchial motor fibres?

Mandibular division of CN V
CN VII
CN IX
CN X

28

What is the nucleus ambiguus?

Mostly motor nucleus
Lies behind inferior olive
Sends fibres to stylopharyngus via CN IX
Sends fibres to levator palati via CN X

29

Which nerves have visceral efferents?

CN III
CN VII
CN IX
CN X

30

From which nucleus do autonomic fibres of CN III originate?

Edinger-Westphal nucleus

31

From which nucleus do autonomic fibres of CN VII originate?

Superior salivatory nucleus

32

From which nucleus do autonomic fibres of CN IX originate?

Inferior salivatory nucleus

33

From which nucleus do autonomic fibres of CN X originate?

Dorsal motor nucleus of vagus

34

How are the sensory nuclei organised?

3 columns laterally

35

What are the three columns of sensory nuclei, from medial to lateral?

Visceral sensory
Somatic sensory
Special sensory

36

Which nerves have visceral afferents?

CN VII
CN IX
CN X

37

Which nerves are sometimes called special visceral afferents, and why?

For taste
- CN VII
- CN IX
- CN X

38

What is the nucleus solitarius?

Extends from pons to level of nucleus gracilis
Rostral = gustatory nucleus
- VII, IX, X: Primary afferents receiving input from taste buds and palate
Caudal = visceral sensory division
- X: Afferents from heart and abdominal viscera
- IX: Baroreceptors and chemoreceptors from carotid body and sinus

39

What are the special senses and their corresponding cranial nerves?

Smell = CN I - olfactory
Sight = CN II - optic
Hearing and equilibrium = CN VIII - vestibulocochlear

40

Which cranial nerves originate from the midbrain?

CN III
CN IV

41

Which cranial nerves originate from the pons?

CN V
CN VI
CN VII
CN VIII

42

Which cranial nerves originate from the medulla?

CN VIII
CN IX
CN X
CN XII

43

What are the functions of the olfactory nerve (CN I)?

Special sensory - sense of smell

44

Where does the olfactory nerve exit the skull?

Cribiform plate of the ethmoid bone?

45

Where is the olfactory cortex?

In insula

46

What are the functions of the optic nerve (CN II)?

Special sensory - vision

47

Where does the optic nerve exit the skull?

Optic canal in sphenoid bone

48

Where does the optic nerve synapse in the thalamus?

Lateral geniculate nucleus

49

What happens at the optic chiasm?

Some axons cross here

50

Where does information from the lateral geniculate nucleus go?

Visual cortex

51

How many extraocular muscles are there?

6

52

What are the extraocular muscles?

Rectus muscles
- Superior rectus
- Inferior rectus
- Lateral rectus
- Medial rectus
Oblique muscles
- Superior oblique
- Inferior oblique

53

Which cranial nerves go to the extraocular muscles?

CN III
CN IV
CN VI

54

What do the cranial nerves innervating the extraocular muscles do?

Act in coordinated fashion

55

Where do CN III, CN IV, and CN VI exit the skull?

Superior orbital fissure, between the wings of the sphenoid bone

56

What is the oculomotor nerve (CN III)?

Somatic motor
- Medial rectus
- Superior rectus
- Inferior rectus
- Inferior oblique
Visceral motor
- Iris (pupils)
- Ciliary muscle (focusing)

57

What are the nuclei of the oculomotor nerve?

Somatic motor: oculomotor nucleus near midline
Visceral motor: lateral to somatic motor nucleus

58

Which cranial nerves enter the orbit?

CN III
CN IV
CN VI
CN V1

59

How do all structures enter the orbit from the skull?

Via superior orbital fissure

60

Why is it relevant that cranial nerves often exit in groups?

Affected in disease together

61

What nerves exit from the cribiform plate?

Olfactory nerve

62

What nerves exit from the optic canal?

Optic nerve

63

What nerves exit from the superior orbital fissure?

Oculomotor nerve
Trochlear nerve
Ophthalmic branch of trigeminal nerve

64

What nerves exit the auditory canal?

Facial nerve
Vestibulocochlear nerve

65

What nerves exit the jugular foramen?

Glossopharyngeal nerve
Vagus nerve
Accessory nerve

66

What nerves exit the hypoglossal foramen?

Hypoglossal nerve

67

What is the pupillary light reflex?

Sensory inputs to brain from retina via CN II
Motor outputs to sphincter pupillae muscle in iris

68

Which nucleus provides the parasympathetic fibres in the oculomotor nerve?

Edinger Westfal nucleus

69

What is the pupillary light reflex used for?

To test midbrain function

70

What is the trigeminal nerve (CN V)?

Somatic sensory
Branchial mtoro

71

What are the functions of the trigeminal nerve?

Sensory: input from face, inside of mouth, and soft palate
Motor: muscles of mastication, and tensor tympani in inner ear

72

With which branch of the trigeminal nerve do its motor fibres travel?

Mandibular branch

73

What does the tensor tympani do?

Dampen sound from chewing

74

Where is the tensor tympani muscle?

In inner ear

75

Where are the trigeminal nuclei?

From midbrain to upper spinal cord

76

What are the nuclei of the trigeminal nerve?

Mesencephalic - mostly proprioception
Chief sensory - mostly fine touch
Spinal trigeminal - particularly important for pain
Motor

77

What is the pathway for somatosensory information from the face?

Primary nerve = trigeminal nerve > synapses in trigeminal nucleus
Secondary nerve crosses midline > passes up brainstem > thalamus
Tertiary nerve from thalamus > cortex

78

How does the trigeminal nerve exit the brainstem?

As two roots
- Motor
- Sensory

79

Which ganglion do the trigeminal sensory nerves travel to?

Trigeminal ganglion

80

What are the branches of the trigeminal nerve?

Ophthalmic - eyes, nose, and forehead
Maxillary - cheeks
Mandibular - jaw, teeth, and tongue

81

What foramina does the trigeminal nerve exit the skulll through?

V1 = superior orbital fissure
V2 = foramen rotundum
V3 = foramen ovale

82

What is the corneal blink reflex?

Sensory: CN V1
Motor: to eyelid by CN VII

83

What is the corneal blink reflex used for?

Test of pontine function

84

What type of nerve is the facial nerve (CN VII)?

Branchial motor
Visceral effernt
Visceral sensory
Somatic sensory

85

What are the roles of the facial nerve?

Motor
- Innervates muscles of facial expression
- Stapedius muscle in ear
- Part of digastric muscle

86

What is the function of the stapedius muscle?

Dampens sound if it's too loud

87

What is the most common cause of CN VII loss of function?

Bell's palsy

88

What is nervus intermedius?

Branch of facial nerve

89

What is the function of nervus intermedius?

Parasympathetic
- Lacrimal glands
- Sublingual and submandibulary salivary glands
Taste
- From anterior 2/3 of tongue and soft palate
Sensation
- From small region near external auditory meatus

90

Which branch of the facial nerve innervates the lacrimal glands?

Greater petrosal

91

Which branch of the facial nerve carries taste information from the tongue?

Chorda tympani

92

Through which foramen does the facial nerve exit the skull?

Stylomastoid foramen

93

What are the five terminal branches of the facial nerve?

Temporal
Zygomatic
Buccal
Mandibular
Cervical

94

What is the function of the five terminal branches of the facial nerve?

Motor innervation for the muscles of facial expression

95

What is the course of the facial nerve?

Brainstem > passes internal acoustic meatus > greater petrosal branch > branch to stapedius > chorda tympani branch > exits skull through stylomastoid foramen > posterior auricular branch > terminal branches

96

What is the relationship between the terminal branches of the facial nerve and the parotid gland?

Go through parotid but don't innervate it

97

What type of nerve is the vestibulocochlear nerve (CN VIII)?

Special sensory - hearing and balance

98

What are the nuclei of the vestibulocochlear nerve?

Dorsal and ventral cochlear nuclei
Four vestibular nuclei

99

Which division of the brainstem are the nuclei of the vestibulocochlear nerve located in?

On border of pons and medulla

100

Where does the vestibulocochlear nerve exit the skull?

Internal acoustic meatus

101

What type of nerve is the glossopharyngeal nerve (CN IX)?

Somatic sensory
Special sensory - taste
Visceral motor
Motor

102

What are the functions of the glossopharyngeal nerve?

Sensory
- Posterior 1/3 of tongue
- Pharynx
- Middle ear
- Carotid body
Taste
- Posterior 1/3 of tongue
Visceral motor
- Parasympathetic to parotid gland
Motor
- Stylopharyngeus

103

Where does the glossopharyngeal nerve exit the skull?

Jugular foramen

104

What is the course of the glossopharyngeal nerve?

Rootlets from different columns of brainstem > jugular foramen lateral and in front of CN X and CN XI > superior and inferior sensory ganglia > between internal and external carotid arteries > follows stylopharyngeus to oropharynx and tongue

105

What type of nerve is the vagus nerve (CN X)?

Branchial motor
Visceral motor
Somatic sensory
Visceral sensory (special) taste
Visceral sensory (general)

106

What is the most important function of the vagus nerv?

Autonomic

107

Which branch of the vagus nerve innervates the vocal cords?

Recurrent laryngeal nerve

108

What are the motor functions of the vagus nerve?

Many striated muscles
- Soft palate
- Pharynx
- Larynx
- Upper oesophagus
- 1 tongue muscle

109

What are the parasympathetic functions of the vagus nerve?

Many
- From pharynx to upper abdomen

110

What are the sensory functions of the vagus nerve?

Pharynx
Larynx
Oesophagus

111

What are the visceral sensory functions of the vagus nerve?

Input from baroreceptors and chemoreceptors of aortic arch
Taste from epiglottis and pharynx

112

What is the gag reflex?

Sensory: CN IX
Motor: CN X

113

What is the gag reflex used for?

Test medullary function

114

Where is the nucleus of the accessory nerve?

Upper 5-6 of cervical spinal cord

115

What is the course of the accessory nerve?

Enters cranium via foramen magnum
Travels with X roots
Exits via jugular foramen

116

What type of nerve is the accessory nerve (CN XI)?

Motor

117

What is the function of the accessory nerve?

Motor input to sternomastoid and upper part of trapezius

118

In general, structures on which side do cranial nerves relate?

Ipsilateral

119

What is the exception to the ipsilateral relationship of structures and cranial nerves?

Trochlear nerve - crosses before exiting midbrain

120

What type of motor neuron are cranial nerves innervating muscle?

Lower motor neurons

121

What type of nerve is the hypoglossal nerve (CN XII)?

Somatic motor

122

What are the functions of the hypoglossal nerve?

Motor innervation to intrinsic and extrinsic muscles of tongue

123

Which muscle of the tongue doesn't the hypoglossal nerve innervate?

Palatoglossus - innervated by CN X

124

Where does the hypoglossal nerve exit the skull?

Hypoglossal foramen

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