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MBBS II HNNS > L08 - Cranial nerves > Flashcards

L08 - Cranial nerves Flashcards

1
Q

List the 12 cranial nerves.

A 
Olfactory 
Optic 
Oculomotor 
Trochlear 
Trigeminal 
Abducens 
Facial 
Vestibulocochlear 
Glossopharyngeal 
Vagus
Accessory 
Hypoglossal
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2
Q

List the 6 types of functional components of cranial nerves.

A

General somatic sensory
General visceral sensory
Special sensory

General somatic motor
Branchial motor
General visceral motor

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3
Q

Distinguish general somatic sensory, general visceral sensory and special sensory functions of CN.

A

General somatic sensory = Perceivestouch,pain,temperature,pressure,vibration, andproprioceptivesensation

General visceral sensory = Perceivessensoryinputfromtheviscera(exceptpain)

Special sensory = Perceivessmell,vision,taste,hearing,andbalance

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4
Q

Distinguish General somatic motor,
Branchial motor,
General visceral motor functions of CN.

A

General somatic motor = Innervatesthemusclesthatdevelopfrom thesomites

Branchial motor = Innervatesthemusclesthatdevelopfromthebranchial (pharyngeal)arches(CNV,VII,IX,X,XI)

General visceral motor = Innervatestheviscera(includingglandsandallsmooth muscles)

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5
Q

List all the CN nuclei found in the midbrain.

A

 Edinger-Westphal preganglionic
 Oculomotor
 Trochlear

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6
Q

List all the CN nuclei found in the Pons.

A 
 Spinal trigeminal (5)
 Principal sensory / pontine trigeminal  (5)
 Trigeminal motor (5)
 Abducens  (6)
 Facial  (7)
 Vestibular (8)

 Superior salivatory
 Inferior salivatory

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7
Q

List all the CN nuclei found in the Medulla.

A 
 Solitary (rostral gustatory, caudal visceral sensory) 
 Spinal trigeminal 
 Vestibular  
 Cochlear
 Ambiguus  
 Dorsal motor vagal 
 Hypoglossal
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8
Q

Embryonic origin of motor and sensory neurons?

A

Basal plate > motor

Alar plate > sensory

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9
Q

List all the CN and associated nuclei with general sensory function.

A

CN V, Trigeminal
CN VII, Trigeminal
CN IX, Trigeminal
CN X, Trigeminal

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10
Q

List all the CN and associated nuclei with visceral sensory function.

A

CN IX, Solitarius

CN X, Solitarius

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11
Q

List all the CN and associated nuclei with special sensory function.

A 
CN I, Mitral cells of olfactory bulb 
CN II, Ganglion cells of retina 
CN VII, Gustatory 
CN VIII, Vestibular 
CN VIII, Cochlear 
CN IX, Gustatory
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12
Q

List all the CN and associated nuclei with Somatic motor function.

A

CN III, Oculomotor
CN IV, Trochlear
CN VI, Abducens
CN XII, Hypoglossal

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13
Q

List all the CN and associated nuclei with branchial motor function.

A 
CN V, Masticator (trigeminal motor)
CN VII, Facial 
CN IX, Ambiguus 
CN X, Ambiguus 
CN XI, Accessory
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14
Q

List all the CN and associated nuclei with Visceral motor function.

A 
CN III, Edinger-Westphal 
CN VII, Superior salivatory 
CN IX, Inferior salivatory 
CN X, Dorsal vagal 
CN X, Ambiguus
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15
Q

Components of the olfactory system?

A

 Olfactory epithelium
 Olfactory bulb
 Olfactory tracts: to olfactory cortex of cerebrum
 Rhinencephalon (= olfactory areas of the brain)

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16
Q

Describe Cells of origin in the olfactory system?

A

Bipolar nerve cells in olfactory epithelium = primary olfactory receptor cells

Dendrite terminates in an olfactory knob where numerous cilia project

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17
Q

Describe Central connection of olfactory system? Location and tract?

A

Olfactory bulbs (where olfactory nerve terminates)

2 tracts:
Medial stria = terminate in anterior commussure to contralateral olfactory structure

Lateral stria = terminate in Primary olfactory (piriform) cortex of ipsilateral temporal lobe

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18
Q

Describe the peripheral distribution of olfactory system? Location and tract?

A

Cilia at the surface of olfactory epithelium in:

  • Superior nasal concha
  • Upper 1/3 of nasal septum

> > Axons of olfactory neurons pack into bundles

> > pass through cribiform plate of ethmoid bone

> > synapse with dendrites of secondary olfactory cells (mitral and tufted cells) in olfactory bulb

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19
Q

Anosmia is a sign of damage of which CN?

A

CN I, Olfactory

Anosmia = loss of sense of smell

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20
Q

List the components of the Optic system.

A 
Retinal ganglion cells 
Optic nerve 
Optic chiasm 
Optic tract 
Lateral geniculate body + Pretectal nuclei of the thalamus 
Visual cortex
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21
Q

Visual field of the left side is processed upside down by the ipsilateral visual cortex. True or False?

A

False

1) Visual field projected to the left retina is processed upside down, left-right reversed
2) Left visual field process by RIGHT visual cortex

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22
Q

Cells of origin of optic system?

A

Retinal ganglion cells (bipolar)

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23
Q

Peripheral distribution of optic system (for vision)?

A

Retinal ganglion cells

> > optic nerves pass through optic canals
converge at optic chiasm
Medial/Nasal retinal ganglion cells project to contralateral side; Lateral/ temporal ganglion cells project to ipsilateral side
Optic tract to Lateral geniculate nucleus of thalamus

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24
Q

Describe central connection of optic system (for vision)?

A

Left, right dorsal Lateral Geniculate Nuclei of thalamus
» Optic radiation fibers
» Visual cortex

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25
Q

2 functions of CN II?

A

Vision

Contribute to Pupillary light reflex, but not the motor effector

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26
Q

Describe the pathway for Consensual pupillary light reflex.

A

Retinal ganglion cells
» Optic nerve
» Optic chiasm
» Pretectal area of midbrain + superior colliculi

 [CN III]
>> Edinger- Westphal nuclei 
>> Oculomotor nerve 
>> Ciliary ganglion 
>> Pupil muscles

CNII terminates at Pretectal area, motor function done by CN III

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27
Q

Consensual pupillary light reflex involves with CN?

A

CN II for sensory

CN III for motor (pupil dilation or constriction)

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28
Q

CN II damage causes what defect?

A

Blindness

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29
Q

2 functional components of CN III and their respective nuclei?

A

1) Somatic motor = Oculomotor nucleus

2) Visceral motor = Edinger- Westphal nucleus

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30
Q

Peripheral distribution of somatic motor division of CN III?

A

Oculomotor nucleus (somatic motor):

1) Medial subnucleus = contralateral innervation to superior rectus
2) Lateral subnuclei = ipsilateral inferior rectus + ipsilateral medial rectus + ipsilateral inferior oblique
3) Central subnucleus = Levator palpebrae superioris

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31
Q

Peripheral distribution of visceral motor division of CN III?

A

Edinger-Wesphal nucleus to ciliary ganglion

1) Pupillae constrictor
2) Ciliary muscle

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32
Q

Compare the function of the somatic and visceral motor divisions of the oculomotor nerve?

A

Somatic, oculomotor nucleus = Precise eyemovementand elevatesupper eyelid

Visceral, Edinger - Wesphal nucleus = Contractionofpupil and accommodationof lens

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33
Q

Mydriasis is a sign of damage to which CN?

A

CN III - Visceral motor division (edinger- Wesphal nucleus)

Mydriasis;lossof pupillarylightand accommodationreflexesinipsilateraleye

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34
Q

Opthalmoplegia is a sign of damage to which CN?

A

CN III - Somatic motor division (Oculomotor nucleus)

Ophthalmoplegia with eyedeviateddownand out,severeptosis(eyelid droop)

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35
Q

Which extraocular muscles are not innervated by CN III?

A

Lateral rectus (CN VI)

and Superior Oblique (CN IV)

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36
Q

Components of CN IV system?

A

Trochlear nucleus at dorsal midbrain (already crossed before emerging from brainstem)

Contralateral superior oblique muscle (peripheral distribution)

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37
Q

Function of CN IV?

A

Intorsion of eye

depression of adducted eye

38
Q

Explain the physiology of abnormal head tilt seen in ppt with diplopia?

A

Diplopia = head tilt to compensate for CN IV lesion causing double vision

Infarcted CN IV weakens contralateral superior oblique extraocular muscle

> > Eye extorted and elevated, cause double vision

> > > Head tilt to opposite side of affected eye = affected eye’s inferior oblique and inferior rectus muscle activated, superior oblique not involved, cause excyclotorsion

> > affected eye becomes level again, cancel double vision

39
Q

List all nuclei and divisions of CN V?

A

4 Nuclei:

  1. Trigeminalmotornucleus(branchial motor)
  2. Mesencephalictrigeminalnucleus(somatic sensory),
  3. Pontinetrigeminalnucleus(somatic sensory),
  4. Spinaltrigeminalnucleus(somatic sensory)

3 Divisions:

  1. Ophthalmic(V1)
  2. Maxillary(V2)
  3. Mandibular(V3)
40
Q

Peripheral distribution and function of Trigeminal ganglion of CN V?

(Trigeminal ganglion
= Spinal trigeminal nucleus + Pontine trigeminal nucleus)

A

Ophthalmic, maxillary, mandibular divisions to mucosa of head, skin of face, head

Somatosensations

41
Q

Peripheral distribution and function of Mesenphalic trigeminal nucleus of CN V?

A
  • Musclesofmastication,
  • peridontal membrane,
  • temporomandibularjoint,
  • externalocularmuscles

Proprioceptive reflexes

42
Q

Peripheral distribution and function of Trigeminal motor nucleus of CN V? (7)

A
  • Temporalis
  • masseter
  • lateralandmedialpterygoids
  • tensor veli palatini
  • tensortympani
  • anterior bellyofdigastric
  • mylohyoid

Mastication

43
Q

Damage to Trigeminal motor nucleus in CN V causes what signs?

A

Deviationofopened jawtoipsilateralside

44
Q

Damage to Mesenphalic trigeminal nucleus in CN V causes what signs?

A

Insignificant effect on proprioceptive reflexes

45
Q

Damage to Trigeminal ganglion in CN V causes what signs?

A

Spinal trigeminal nucleus + Pontine trigeminal nucleus affected

Lossoffacialsensationsand cornealreflexonstimulation ipsilaterally

46
Q

Components of CN VI?

A

Abducens nucleus at inferior pons

Superior orbital fissure

Lateral rectus muscle

47
Q

CN VI damage results in what symptom?

A

Normal function = abduct eye

Diplopia,medial deviations;inability toabductthe affectedeye

48
Q

Location and anatomical division of Facial nerve?

A

Location: arisesatthejunctionbetweentheponsand medulla

anatomicallyhastwodivisions,themotorrootand theothersmallerintermediatenerve

49
Q

Functional divisions of the facial nerve and associated nuclei.

A

Branchial motor = Facial nucleus

Visceral motor = Superior salivatory nucleus

Special sensory = Geniculate ganglion&raquo_space; Solitary nucleus

General sensory = Geniculate ganglion&raquo_space; Spinal trigeminal n.

50
Q

Central connections of the Facial nerve divisions?

A

Geniculate ganglion has 2 central connections

1) Special sensory&raquo_space; Solitary nucleus (rostral)
2) General sensory&raquo_space; Spinal trigeminal nucleus (caudal)

Facial nucleus (branchial motor) and Superior salivatory nuceli (visceral parasym.) have no central connections

51
Q

Peripheral distribution and function of facial nucleus of CN VII?

A

Facialmuscles,buccinator, stapedius,stylohyoid,posterior bellyofdigastric,platysma, occipitalis

Function:
- Facial expression: Upper = bilateral control/ Lower = contralateral control

  • Articulation
  • Winking
  • Ingestion of food, drink
52
Q

Peripheral distribution and function of superior salivatory nucleus of CN VII?

A

1) Major petrosal nerve to nerve of pterygoid canal to pterygopalatine ganglion

> > Postganglionics via maxillary nerve to lacrimal gland and mucosal glands of nasal cavity and palate

2) Chorda tympani to lingual nerve to submandibular ganglion

> > Postganglionics to submandibular, and sublingual glands

Function = Nasal and lacrimal secretions + Salivary secretion

53
Q

Peripheral distribution and function of geniculate ganglion of CN VII for special sensory function?

A

nucleus solitarius (gustatory rostral portion)

> > Geniculate ganglion

> > Taste buds in anterior 2/3 of tongue

Function = taste

54
Q

Peripheral distribution and function of geniculate ganglion of CN VII for general sensory function?

A

Pontine trigeminal nucleus (caudal part)
» Geniculate ganglion
» Posteriorauricular region,external auditory meatus,tympanic membrane

Function = Somatosensations

55
Q

Decreased salivation + dry mouth is a sign of which CN damage?

A

Superior salivatory nucleus of facial nerve

56
Q

Damage to superior salivatory nucleus of CN VII causes what symptoms?

A

Loss of lacrimation

Decreased salivation

Dry mouth

57
Q

Damage to facial nucleus of CN VII causes what signs?

A

Paralysis of ipsilater upper and lower facial muscles

58
Q

Damage to geniculate ganglion of CN VII causes what signs?

A

Loss of taste in anterior 2/3 of tongue

Insignificant loss of somatosensation in posterior auricular region

59
Q

Location and functional division of CN VIII?

A

Vestibulocochlear nerve:leave thelateralaspectofthejunctionbetween theponsandthemedulla

Special sensory > balance
Special sensory > Hearing

60
Q

Cells of origin and central connections for vestibulocochlear nerve?

A

Vestibular ganglion&raquo_space; vestibular nuclei, cerebellum (balance)

Cochlear / spiral ganglion&raquo_space; dorsal, ventral cochlear nucleus (hearing)

61
Q

Peripheral distribution of vestibulocochlear nerve?

A

Balance&raquo_space; Hair cells of ampullary crests in semicircular ducts,
maculae of saccule, utricle

Hearing&raquo_space; Hair cells ofspiral organ of Corti

62
Q

Damage to CN VIII causes what signs?

A

Vestibular ganglion lesion = Vertigo, dysequillibrium, nystagmus

Spiral ganglion = Neural deafness

63
Q

Proprioception is processed by CN VIII only. True or False.

A

False

Provided by information from the visual, conscious proprioceptive and vestibular systems

64
Q

Location and functional divisions of CN IX?

A

Upper part of medulla oblongata

Mixed nerve with motorandsensoryfunctions:

  • Branchial motor
  • Visceral motor
  • Special sensory
  • General sensory
  • Visceral sensory
65
Q

5 cells of origin and central connections for CN IX?

A

Cells of origin:

  • Branchial motor = Nucleus ambiguus rostral
  • Visceral motor = Inferior salivatory nucleus
  • Special sensory = Inferior petrosal ganglion (» solitary nucleus, rostral)
  • General sensory = Inferior and superior ganglion (» Spinal trigeminal nucleus)
  • Visceral sensory = Inferior ganglion (» solitary nucleus)
66
Q

Central connections of CN IX?

A

(Taste)
Inferior petrosal ganglion&raquo_space; Solitary nucleus (rostral)

(Somatosensations)
Inferior and superior gangion&raquo_space; Spinal trigeminal nucleus

(Reflexes)
Inferior ganglion&raquo_space; Solitary nucleus

(Elevate pharynx) Nucleus ambiguus and (Salivary secretion) Inferior salivatory nucleus have no ‘central connections’ – already nucleus

67
Q

Peripheral distribution and function of branchial motor part of CN IX?

A

Nucleus ambiguus&raquo_space;
 Stylopharyngeus
 Superiorpharyngeal constrictor

Elevate pharynx

68
Q

Peripheral distribution and function of visceral motor part of CN IX?

A

Inferior salivatory nucleus&raquo_space;Tympanic plexus to minor petrosal nerve to otic ganglion

Postganglionics via auriculotemporal nerve to PAROTID GLAND

Increase salivation

69
Q

Peripheral distribution and function of special sensory part of CN IX?

A

solitary nucleus&raquo_space;Inferior petrosal ganglion&raquo_space; Taste buds in posterior 1/3 of tongue

Taste

70
Q

Peripheral distribution and function of general sensory part of CN IX?

A

spinal trigeminal nucleus&raquo_space; Inferior and superior ganglion&raquo_space;

  • Anterior surface epiglottis
  • Root of tongue
  • Border of soft palate
  • Uvula
  • Tonsil
  • Pharynx
  • Auditory tube and middle ear

Somatosensations

71
Q

Peripheral distribution and function of visceral sensory part of CN IX?

A

solitary nucleus&raquo_space; Inferior ganglion&raquo_space; Carotid sinus and bulb

72
Q

Patient presents with slight dysphagia, constant dry mouth, loss of taste in posterior 1/3 of tongue. Which CN is damaged?

A

CN IX

Slight dysphagia = Nucleus ambiguus (branchial motor)

Dry mouth = Inferior salivatory nucleus (visceral motor)

Loss of taste at post 1/3 tongue = Inferior petrosal ganglion (special sensory)

73
Q

Damage to inferior and superior ganglion of CN IX produces what signs?

A

Spinal trigeminal nucleus&raquo_space; Inf. and sup. ganglion&raquo_space;somatosensation in pharynx

Anethesia of tonsillar region

Loss of gag reflex from ipsilateral stimulus

74
Q

Location and anatomical division of spinal accessory nerve?

A

CN XI:

  • Cranial root from medulla
  • Spinal root from superior spinal cord, pass into cranium via foramen magnum
75
Q

Function division of CN XI?

A
  • Cranial part:
    Branchial motor = Nucleus ambiguus
  • Spinal part:
    Branchial motor = Motor neurons of spinal accessory nucleus in C1- C6
76
Q

Peripheral distribution and function of CN XI?

A

Cranial part = communicate with vagal* branches to muscles of pharynx and larynx = Swallowing and vocalization

Spinal part = corticospinal tract through jugular foramen:
ipsilateral Sternocleidomastoid (SCM) + contralateral Trapezius muscles = Movements of head and shoulder
77
Q

Lesion in CN IX causes what signs?

A

Weakness in:
Turning head toward opposite side

Shrugging shoulder

78
Q

Location and cell of origin of CN XII?

A

Arise from medulla&raquo_space; exit skull via hypoglossal canal

Hypoglossal nucleus

79
Q

Peripheral distribution and function of CN XII?

A

Muscles of the tongue:
-Extrinsic: Styloglossus + Hyoglossus + Genioglossus NOT palatoglossus

-Intrinsic muscles

Tongue movement

80
Q

Lesion of CN XII causes what signs?

A

Wasting of ipsilateral tongue muscles and deviation to ipsilateral side on protrusion

81
Q

List all the organs with vagal innervation.

A

Parasympathetic fibers to:

Heart, lungs, bronchi, trachea, larynx, pharynx, gastrointestinal tract, external ear

82
Q

4 cells of origin and their functional divisions of CN X.

A

Nucleus ambiguus = branchial motor

Dorsal motor nucleus of vagus and region of nucleus ambiguus = visceral motor

Inferior nodose ganglion&raquo_space; solitary nucleus = visceral sensory + reflexes

Superior jugular ganglion&raquo_space; spinal trigeminal nucleus = general sensory

83
Q

Central connections of CNX?

A

Inferior nodose ganglion&raquo_space; Solitary nucleus

Superior jugular ganglion&raquo_space; Spinal trigeminal nucleus (caudal)

84
Q

Peripheral distribution and function of vagus nerve: nucleus ambiguus?

A

Branchial motor

Palate,pharyngealconstrictors,intrinsicmusclesoflarynx

Deglutition andphonation

85
Q

Peripheral distribution and function of vagus nerve: Dorsal motor nucleus of vagus and region of nucleus ambiguus?

A

 Cardiac nerves, plexus to ganglia of heart &raquo_space; Cardiac depressor

 Pulmonary plexuses to ganglia of respiratory tree&raquo_space; Bronchoconstrictor

 Esophageal, gastric, celiac, superior and inferior mesenteric plexuses to myenteric and submucous ganglia of digestive tract down to proximal 2/3 transverse colon&raquo_space; GI peristalsis and secretion

86
Q

Peripheral distribution and function of vagus nerve: Inferior nodose ganglion?

A

1) Taste buds in epiglottis = taste
2) Posterior surface of epiglottis, pharynx, larynx, trachea and bronchi, GI tract from esophagus to transverse colon = visceral sensations and reflexes
3) Aortic sinus and bulb = reflexes

87
Q

Peripheral distribution and function of vagus nerve: Superior jugular ganglion?

A

External ear and meatus

Somatosensation

88
Q

Dysphagia + hoarsness + paralysis of soft palate is damage to which part of which CN?

A 
Vagus 
Nucleus ambiguus (branchial motor)
89
Q

Anesthesia of ipsilateral pharynx and larynx = damage to which CN?

A

Vagus

Inferior nodose ganglion

90
Q

Damage to superior jugular ganglion of vagus causes what signs?

A

Anesthesia of ipsilateral external auditory meatus

MBBS II HNNS (57 decks)

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