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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
2 functions of CN II?
Vision Contribute to Pupillary light reflex, but not the motor effector
26
Describe the pathway for Consensual pupillary light reflex.
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
27
Consensual pupillary light reflex involves with CN?
CN II for sensory | CN III for motor (pupil dilation or constriction)
28
CN II damage causes what defect?
Blindness
29
2 functional components of CN III and their respective nuclei?
1) Somatic motor = Oculomotor nucleus | 2) Visceral motor = Edinger- Westphal nucleus
30
Peripheral distribution of somatic motor division of CN III?
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
31
Peripheral distribution of visceral motor division of CN III?
Edinger-Wesphal nucleus to ciliary ganglion 1) Pupillae constrictor 2) Ciliary muscle
32
Compare the function of the somatic and visceral motor divisions of the oculomotor nerve?
Somatic, oculomotor nucleus = Precise eye movement and  elevates upper eyelid Visceral, Edinger - Wesphal nucleus = Contraction of pupil  and  accommodation of  lens
33
Mydriasis is a sign of damage to which CN?
CN III - Visceral motor division (edinger- Wesphal nucleus) Mydriasis; loss of pupillary light and  accommodation reflexes in ipsilateral eye
34
Opthalmoplegia is a sign of damage to which CN?
CN III - Somatic motor division (Oculomotor nucleus) Ophthalmoplegia with  eye deviated down and  out, severe ptosis (eyelid  droop)
35
Which extraocular muscles are not innervated by CN III?
Lateral rectus (CN VI) and Superior Oblique (CN IV)
36
Components of CN IV system?
Trochlear nucleus at dorsal midbrain (already crossed before emerging from brainstem) Contralateral superior oblique muscle (peripheral distribution)
37
Function of CN IV?
Intorsion of eye depression of adducted eye
38
Explain the physiology of abnormal head tilt seen in ppt with diplopia?
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
List all nuclei and divisions of CN V?
4 Nuclei: 1. Trigeminal motor nucleus(branchial motor) 2. Mesencephalic trigeminal nucleus (somatic sensory),  3. Pontine trigeminal nucleus (somatic sensory),  4. Spinal trigeminal nucleus (somatic sensory) 3 Divisions: 1. Ophthalmic (V1) 2. Maxillary (V2) 3. Mandibular (V3)
40
Peripheral distribution and function of Trigeminal ganglion of CN V? (Trigeminal ganglion = Spinal trigeminal nucleus + Pontine trigeminal nucleus)
Ophthalmic, maxillary, mandibular divisions to mucosa of head, skin of face, head Somatosensations
41
Peripheral distribution and function of Mesenphalic trigeminal nucleus of CN V?
- Muscles of mastication,  - peridontal membrane,  - temporomandibular joint,  - external ocular muscles Proprioceptive reflexes
42
Peripheral distribution and function of Trigeminal motor nucleus of CN V? (7)
- Temporalis - masseter - lateral and medial pterygoids  - tensor veli palatini - tensor tympani - anterior  belly of digastric - mylohyoid Mastication
43
Damage to Trigeminal motor nucleus in CN V causes what signs?
Deviation of opened  jaw to ipsilateral side
44
Damage to Mesenphalic trigeminal nucleus in CN V causes what signs?
Insignificant effect on proprioceptive reflexes
45
Damage to Trigeminal ganglion in CN V causes what signs?
Spinal trigeminal nucleus + Pontine trigeminal nucleus affected Loss of facial sensations and  corneal reflex on stimulation  ipsilaterally
46
Components of CN VI?
Abducens nucleus at inferior pons Superior orbital fissure Lateral rectus muscle
47
CN VI damage results in what symptom?
Normal function = abduct eye Diplopia, medial  deviations; inability  to abduct the affected eye
48
Location and anatomical division of Facial nerve?
Location: arises at the junction between the pons and  medulla anatomically has two divisions, the motor root and  the other smaller intermediate nerve
49
Functional divisions of the facial nerve and associated nuclei.
Branchial motor = Facial nucleus Visceral motor = Superior salivatory nucleus Special sensory = Geniculate ganglion >> Solitary nucleus General sensory = Geniculate ganglion >> Spinal trigeminal n.
50
Central connections of the Facial nerve divisions?
Geniculate ganglion has 2 central connections 1) Special sensory >> Solitary nucleus (rostral) 2) General sensory >> Spinal trigeminal nucleus (caudal) Facial nucleus (branchial motor) and Superior salivatory nuceli (visceral parasym.) have no central connections
51
Peripheral distribution and function of facial nucleus of CN VII?
Facialmuscles, buccinator, stapedius,stylohyoid,posterior  bellyofdigastric, platysma,  occipitalis Function: - Facial expression: Upper = bilateral control/ Lower = contralateral control - Articulation - Winking - Ingestion of food, drink
52
Peripheral distribution and function of superior salivatory nucleus of CN VII?
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
Peripheral distribution and function of geniculate ganglion of CN VII for special sensory function?
nucleus solitarius (gustatory rostral portion) >> Geniculate ganglion >> Taste buds in anterior 2/3 of tongue Function = taste
54
Peripheral distribution and function of geniculate ganglion of CN VII for general sensory function?
Pontine trigeminal nucleus (caudal part) >> Geniculate ganglion >> Posterior auricular region,external auditory meatus, tympanic membrane Function = Somatosensations
55
Decreased salivation + dry mouth is a sign of which CN damage?
Superior salivatory nucleus of facial nerve
56
Damage to superior salivatory nucleus of CN VII causes what symptoms?
Loss of lacrimation Decreased salivation Dry mouth
57
Damage to facial nucleus of CN VII causes what signs?
Paralysis of ipsilater upper and lower facial muscles
58
Damage to geniculate ganglion of CN VII causes what signs?
Loss of taste in anterior 2/3 of tongue Insignificant loss of somatosensation in posterior auricular region
59
Location and functional division of CN VIII?
Vestibulocochlear nerve: leave  the lateral aspect of the junction between  the pons and the medulla Special sensory > balance Special sensory > Hearing
60
Cells of origin and central connections for vestibulocochlear nerve?
Vestibular ganglion >> vestibular nuclei, cerebellum (balance) Cochlear / spiral ganglion >> dorsal, ventral cochlear nucleus (hearing)
61
Peripheral distribution of vestibulocochlear nerve?
Balance >> Hair cells of ampullary crests in semicircular ducts, maculae of saccule, utricle Hearing >> Hair cells of spiral organ of Corti
62
Damage to CN VIII causes what signs?
Vestibular ganglion lesion = Vertigo, dysequillibrium, nystagmus Spiral ganglion = Neural deafness
63
Proprioception is processed by CN VIII only. True or False.
False Provided by information from the visual, conscious proprioceptive and vestibular systems
64
Location and functional divisions of CN IX?
Upper part of medulla oblongata Mixed nerve with  motor and sensory functions: - Branchial motor - Visceral motor - Special sensory - General sensory - Visceral sensory
65
5 cells of origin and central connections for CN IX?
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
Central connections of CN IX?
(Taste) Inferior petrosal ganglion >> Solitary nucleus (rostral) (Somatosensations) Inferior and superior gangion >> Spinal trigeminal nucleus (Reflexes) Inferior ganglion >> Solitary nucleus (Elevate pharynx) Nucleus ambiguus and (Salivary secretion) Inferior salivatory nucleus have no 'central connections' -- already nucleus
67
Peripheral distribution and function of branchial motor part of CN IX?
Nucleus ambiguus >>  Stylopharyngeus  Superiorpharyngeal constrictor Elevate pharynx
68
Peripheral distribution and function of visceral motor part of CN IX?
Inferior salivatory nucleus >>Tympanic plexus to minor petrosal nerve to otic ganglion Postganglionics via auriculotemporal nerve to PAROTID GLAND Increase salivation
69
Peripheral distribution and function of special sensory part of CN IX?
solitary nucleus >>Inferior petrosal ganglion >> Taste buds in posterior 1/3 of tongue Taste
70
Peripheral distribution and function of general sensory part of CN IX?
spinal trigeminal nucleus >> Inferior and superior ganglion >> - Anterior surface epiglottis - Root of tongue - Border of soft palate - Uvula - Tonsil - Pharynx - Auditory tube and middle ear Somatosensations
71
Peripheral distribution and function of visceral sensory part of CN IX?
solitary nucleus >> Inferior ganglion >> Carotid sinus and bulb
72
Patient presents with slight dysphagia, constant dry mouth, loss of taste in posterior 1/3 of tongue. Which CN is damaged?
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
Damage to inferior and superior ganglion of CN IX produces what signs?
Spinal trigeminal nucleus >> Inf. and sup. ganglion >>somatosensation in pharynx Anethesia of tonsillar region Loss of gag reflex from ipsilateral stimulus
74
Location and anatomical division of spinal accessory nerve?
CN XI: - Cranial root from medulla - Spinal root from superior spinal cord, pass into cranium via foramen magnum
75
Function division of CN XI?
- Cranial part: Branchial motor = Nucleus ambiguus - Spinal part: Branchial motor = Motor neurons of spinal accessory nucleus in C1- C6
76
Peripheral distribution and function of CN XI?
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
Lesion in CN IX causes what signs?
Weakness in: Turning head toward opposite side Shrugging shoulder
78
Location and cell of origin of CN XII?
Arise from medulla >> exit skull via hypoglossal canal Hypoglossal nucleus
79
Peripheral distribution and function of CN XII?
Muscles of the tongue: -Extrinsic: Styloglossus + Hyoglossus + Genioglossus **NOT palatoglossus** -Intrinsic muscles Tongue movement
80
Lesion of CN XII causes what signs?
Wasting of ipsilateral tongue muscles and deviation to ipsilateral side on protrusion
81
List all the organs with vagal innervation.
Parasympathetic fibers to: Heart, lungs, bronchi, trachea, larynx, pharynx, gastrointestinal tract, external ear
82
4 cells of origin and their functional divisions of CN X.
Nucleus ambiguus = branchial motor Dorsal motor nucleus of vagus and region of nucleus ambiguus = visceral motor Inferior nodose ganglion >> solitary nucleus = visceral sensory + reflexes Superior jugular ganglion >> spinal trigeminal nucleus = general sensory
83
Central connections of CNX?
Inferior nodose ganglion >> Solitary nucleus Superior jugular ganglion >> Spinal trigeminal nucleus (caudal)
84
Peripheral distribution and function of vagus nerve: nucleus ambiguus?
Branchial motor Palate, pharyngeal constrictors, intrinsic muscles of larynx Deglutition and phonation
85
Peripheral distribution and function of vagus nerve: Dorsal motor nucleus of vagus and region of nucleus ambiguus?
 Cardiac nerves, plexus to ganglia of heart >> Cardiac depressor  Pulmonary plexuses to ganglia of respiratory tree >> Bronchoconstrictor  Esophageal, gastric, celiac, superior and inferior mesenteric plexuses to myenteric and submucous ganglia of digestive tract down to proximal 2/3 transverse colon >> GI peristalsis and secretion
86
Peripheral distribution and function of vagus nerve: Inferior nodose ganglion?
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
Peripheral distribution and function of vagus nerve: Superior jugular ganglion?
External ear and meatus Somatosensation
88
Dysphagia + hoarsness + paralysis of soft palate is damage to which part of which CN?
``` Vagus Nucleus ambiguus (branchial motor) ```
89
Anesthesia of ipsilateral pharynx and larynx = damage to which CN?
Vagus | Inferior nodose ganglion
90
Damage to superior jugular ganglion of vagus causes what signs?
Anesthesia of ipsilateral external auditory meatus

MBBS II HNNS (57 decks)

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