09 15 2014 Brainstem Flashcards

1
Q

function of brainstem

A
  1. conduit function
  2. cranial nerve function
  3. integrative function
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2
Q

Sensory CNs

A

1,2,8

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3
Q

Motor CNs

A

3,4,6,9,11

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4
Q

Mixed CNs

A

5,7,9,10

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5
Q

Mnemonics

A
  1. Some
  2. Say
  3. Money
  4. Matters
  5. But
  6. My
  7. Brother
  8. Says
  9. Big
  10. Brains
  11. Matter
  12. most
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6
Q

Motor Somatic Efferent nuclei

A

relates to the framework of the body (skeletal muscles that originates from embryonic somites– extra ocular and tongue muscles)

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7
Q

Motor Visceral General nuclei (efferent)

A

Relates to efferent fibers that activate the viscera or organs

-preganglionic parasympathetic for cranial, thoracic, and abdominal smooth muscle (viscera)

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8
Q

Motor visceral special nuclei (efferent)

A

activates striated muscle

  • muscle from embryonic branchial arches
  • facial expression, jaw muscles, laryngeal and pharyngeal muscles, sternocleidomastoid.
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9
Q

Sensory Somatic afferent nuclei

A

caries information about the changes in environment from the framework of the body

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10
Q

Sensory General Somatic Afferent nuclei

A

refers to the impulse that begin at or near the body surface

-pain, temperature, touch, pressure

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11
Q

Sensory Special Somatic Afferent

A

highly specialized sensory system–

  • vision (light)
  • hearing (sound)
  • Taste
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12
Q

Sensory General Visceral Afferent

A

receptors from in/around mucus membrane or in organ walls impulses about physical distention or chemical composition of substances or organic wall.

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13
Q

Sensory Special Visceral Afferent

A

refers to specialized chemical stimuli

-smell and tase

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14
Q

Hypoglossal nerve
(general)

(what in intervates is on another card)

A

motor– General somatic efferent GSE (ONLY)

  • LMN exits between olive and pyramid (medulla) LMN is ipsilateral
  • hypoglossal triangle – floor of fourth ventricle
  • Controls movement of tongue and maintains muscle tone

-UMN (corticobulbar tract) is mostly contralateral

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15
Q

What muscles does the hypoglossal nerve innervate?

A

innervates all intrinsic muscles and all but one of the extrinsic tongue muscles

-does not innervate palatoglossus muscle (CN X)

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16
Q

CN XII (Cn # 12) nucleus is innervated by:

A
  1. -Corticobulbar pathway (is mainly crossed for XII)
    - voluntary movement
  2. Reticular neurons for automatic movements
    - control of stereotyped movements while eating and swallowing.
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17
Q

Upper motor lesion in Hypoglossal cranial nerve?

A
  • Tongue deviates to the side opposite of the damage
  • if lesion on the left, the right side of the tongue is weak. Tongue is pushed to right side because of weakened muscles
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18
Q

lower motor lesion in Hypoglossal cranial nerve?

A
  • tongue deviates to the same side of damage
  • Damage is on the left (right corticobulbar tract has already crossed and is now on the left). The tongue deviates to the left because left muscles are weak.)
  • Muscle atrophy in tongue
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19
Q

What happens when you have a bilateral lesion of CN 12?

A
  • disability in speaking

- severe swallowing difficulty of food

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20
Q

Common causes of CN 12 lesions

A
  • motor neuron disease
  • demyelination
  • bleeding
  • tumors of medulla and base of skull

(LMN disease)

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21
Q

Spinal Accessory nerve - composition

A

MOTOR ONLY! composed of fibers from medial motor nuclei in ventral horn of caudal medulla and the accessory nucleus (close to pyramidal decussation).

LMN in medulla and cervical cord (C1-C5)

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22
Q

Spinal Accessory nerve : branchial motor part

A

Ipsilateral innervation of sternomastoid and trapezius muscle.
(spinal part)

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23
Q

Spinal Accessory nerve: Visceral motor part

A

Joins CN X to control larynx

accessory part

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24
Q

Lesion of Spinal Accessory nerve

A

Head turns to side opposite of lesion.

Explanation:
Sternomastoid m. turns head to opposite side. So a lesion would cause the more powerful side to take over, so therefore, the head will face the side that has been lesioned

  • ipsilateral shoulder drop
  • weakened voice or hoarseness
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25
Q

Vagus Nerve General

A

BOTH Motor and Sensory

Forms Vagal triangle (floor of 4th ventricle)

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26
Q

Vagus Nerve (efferents vs. afferents)

A

2 Efferents: (MOTOR)

  1. General Viseral Efferent (GVE)
    Preganglionic parasympathetic
    heart, lungs, GI (to splenic flexure)
    • neurotransmitter ACh
  2. Special Visceral Efferent (SVE)
    -Pharyngeal and laryngeal muscles (swallowing and vocalization)

3 Afferents: (SENSORY)

  1. General Somatic Afferent
    • pharynx, meninges, small region of external ear.
  2. Special Visceral Afferent
    • taste from epiglottis and pharynx
  3. Genreal Visceral Afferent
    • chemoreceptors, baroreceptors of aortic arch
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27
Q

Where are the Vagus Cranial nerve GVE fibers located?

A

GVE- general visceral efferent
-preganglionic parasympathetic
heart lungs and GI

  • Dorsal motor nucleus of X
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28
Q

Where are the SVE fibers of CN # 10 located?

A

Special Visceral Efferents:
-pharyngeal and upper esophageal muscles
(Swallowing and gag reflex)
-Larynx muscles (vocalization)

Nucleus Ambiguus

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29
Q

Where are the GSA fibers located (for CN 10)?

A

GSA= general somatic sensory
Pharynx, larynx, meninges, small region of outer ear
- afferents join nucleus of CN 5

30
Q

Where are the Special Visceral afferent fibers of the CN 10 located?

A

SVA - taste of epiglottis and posterior pharynx

Nucleus Solitarius

31
Q

Where are the GVA fibers of CN 10 located?

A

General visceral afferents- chemo receptors, baroreceptors of aortic arch, cardiorespiratory system, digestive system

Nucleus Solitarius

32
Q

Complete lesion of CN 10 can cause what?

Unilateral lesion of vagus nerve can cause what?

A
  • Fatal
  • widespread dysfunction of the palate, pharynx and larynx

(if lesion of right CN 10)
-right palatal arch sagging, deviation of uvula to the left, right vocal muscles paralysis

33
Q

Glossopharyngeal Nerve (general)

A

BOTH sensory and motor

34
Q

Glossopharyngeal Nerve

-efferents vs. afferents

A

2 Efferents (Motor)

  1. GVE - general visceral efferent
    - preganglionic parasympathetic to parotid gland
  2. SVE special visceral efferent – stylopharyngeal muscles

3 Afferents (Sensory)

  1. GSA- general somatic afferent
    - pharnyx, posterior 1/3 of tongue, middle ear, small region of external ear
  2. SVA– special visceral afferent
    - taste from posterior 1/3 of tongue
  3. GVA- general visceral afferent
    - chemorecepors and baroreceptors from carotid body.
35
Q

Where are the GVE fibers of CN 9 located?

A

General visceral efferent:
-preganglionic parasympathetics to parotid gland

  • inferior salivary nucleus (in PONS)
  • –> work their way to otic ganglion = parasympathetic to parotid gland
36
Q

Where are the SVE fibers of CN 9 located?

A

Special visceral efferent– branchial motor

  • stylopharyngeal muscles
  • elevates pharynx during talking and swallowing

Nucleus Ambiguus

37
Q

Lesions at N. ambiguous causes what?

A

Affects CN 10: SVE fibers
-pharynx, larynx, meninges, small region of outer ear

Affects CN 9 : SVE fibers
-pharynx, posterior 1/3 of tongue, middle ear, small region of external ear.

LMN are going to be affected – muscle atrophy!!

  • poliomyelitis
  • Ischaemic lesions
  • Intramedullary tumors
  • Motor Neurons disease
  • Neuroma
  • Myastenia gravis

Glossopharyngeal neuralgia– episodes of severe throat and ear pain.

38
Q

Vascular supply to the medulla?

A

Medial : Anterior Spinal Artery
Lateral : PICA
Rostral: Vertebral artery- paramedian branches

39
Q

Anterial spinal artery– regions it hits in medulla

A

Pyramids, medial leminiscus, hypoglossyl nucleus

40
Q

Vertebral artery helps supply what structure in the medulla?

A

Inferior olivary nucleus

41
Q

What structures in the medulla does the PICA play a big role in?

A

Solitary nucleus, Nucleus Ambiguus

42
Q

Meduallry syndrome. What if it happens on the left side?

A

Blockage of Anterior spinal artery

  1. right corticospinal tract
  2. left 1/2 of tongue
  3. right touch/vibration lost
43
Q

Lateral Medullary Syndrome?

A

Blockage of PICA

-hits N. Soletarious and other sensory parts (pain and temperature)

44
Q

CN 5 (general)

A

Both motor and sensory

Muscles of mastications, proprioception, touch and temperature, pain and temperature

45
Q

Types of fibers in CN 5?

A

SVE: special visceral efferent (branchial motor)
-muscles of mastication and tensor tympani muscle

GSA: general somatic afferent: proprioception (pons–> midbrain); Touch and temperature (pons); Pain and temperature (pons –> spinal cord)

46
Q

There are 4 main things that the CN 5 does? aka What pathways (sensory/ motor) does it contribute too?

A
  1. motor (pons)
  2. propriception (pons–> midbrain)
  3. Touch and temperature (pons)
  4. pain and temperature (mid pons–C2-C3 spinal cord)
47
Q

Pain and temperature pathway of CN5:

A

GSA - general somatic afferent fibers

  • ipsilateral impulses of pain temerpature some touch from head, face and neck
  • spinal trigeminal tract

1st order neuron is in trigeminal ganglion
2nd order = Spinal nucleus of medulla
3rd = VPM (thalamus) (crossed projection to VPM)

48
Q

Touch pathway of CN 5:

A

GSA- touch and pressure from face, mouth anterior 2/3 of tongue, nasal sinuses

1st order neuron : trigeminal ganglion
2nd order neuron in main/principle/chief nucleus — crosses immediately to VPM.
3rd neuron continues to homonculus

49
Q

Proprioception of CN 5:

A

GSA – primary sensory neurons innervate muscles of mastication, project to motor nucleus of 5.

1st neuron is in CNS – mesencephalic nucleus

50
Q

Motor fivers for CN 5 pathway:

A

SVE:
innervates muscles of mastication and tensor tympani

Nucleus: Trigeminal motor nucleus
-ocated mid pons medial to the chief sensory nucleus

51
Q

What happens if there is a lesion in the CN5 ?

A

when chin opens, it deviates away from lesion

52
Q

What is trigeminal neuralgia (Tic doloureux)

A
  • recurrent episode of brief severe pain lasting from seconds to a few minutes (V2-V3)
  • facial sensation is normal
53
Q

What are some things that may cause sensory loss via CN 5?

A
  • trauma
  • Herpes Zoster
  • Aneurysms
  • Metabolic disease
54
Q

Facial nerve (general) and fibers

A

Both sensory and motor

2 efferent

  1. SVE
    - special visceral efferent: mucles of expression and stapedius muscle
  2. GVE
    - general visceral efferent: pre ganglion sympathetic for lacrimal, and all salivary glands EXCEPT parotid (CN9)

3 afferent
1. GSA- general somatic afferent: small region of outer ear

  1. SVA- special visceral afferent: taste to anterior 2/3 of tongue
  2. GVA- general visceral afferent: mucosal membrane of nasopharynx
55
Q

Facial motor nucleus (CN 7)

A

SVE: muscles of facial expression and stapedius

Turns around abducens nucleus and forms the Facial colliculi – fibers exit in corder of ponto-medllary junction.

Present in pons close to mandibular nucleus of 5.

56
Q

CN7 - role in corneal reflex?

  • receptor?
  • Afferent?
  • 1st synapse?
  • second synapse?
  • muscle?
A
  1. cornea
  2. opthalmic nerve of V
  3. Spinal nucleus of trigeminal
  4. Facial nucleus
  5. orbicularis oculi
57
Q

CN7 role in sucking reflex

  • receptor?
  • Afferent?
  • 1st synapse?
  • second synapse?
  • muscle?
A
  1. lips
  2. Mandibular nerve CN V
  3. Pontine nucleus of V
  4. Facial nucleus
  5. orbicularis oculi
58
Q

CN7 role in blinking to light reflex

  • receptor?
  • Afferent?
  • 1st synapse?
  • second synapse?
  • muscle?
A
  1. retina
  2. Opthalmic nerve
  3. Superior colliculus
  4. Facial nerve
  5. orbicularis oculi
59
Q

CN7 role in blinking to noise

  • receptor?
  • Afferent?
  • 1st synapse?
  • second synapse?
  • muscle?
A
  1. Cochlea
  2. Cochlea nucleus
  3. Inferior colliculus
  4. Facial nucleus
  5. orbicularis oculi
60
Q

CN7 role in sound attenuation

  • receptor?
  • Afferent?
  • 1st synapse?
  • second synapse?
  • muscle?
A
cochlea
cochlea nucleus
superior olivary nucleus
Facial nucleus
Stapedius muscle
61
Q

Superior Salivatory nucleus (SSNU)

A

GVE- general visceral efferents – preganglion parasympathetic innervation for lacrimation and salivation (except parotid gland).

62
Q

Facial nerve- rostral solitary nucleus

A

SVA- special visceral afferent : taste from anterior two thirds of tongue

63
Q

Facial nerve– pain, temperature, touch, pressure

A

GSA- general somatic afferent: back of the outer ear (also Cn 9, 10)

Information travels into the spinal trigeminal nucleus and then information crosses as part of trigemino-thalamic projections to thalamus (VPM)

64
Q

Vascular supply to pons?

A

Basilar artery

  1. Superior cerebellar artery = rostral pons
  2. Basilar paramedian arteris = medial region in pons cross section
  3. AICA = lateral and caudal pons
65
Q

Tracts in the pons that could be affected if anything happened to paramedial branches of the basilar artery

A

-pontine nucleus, Medial lemniscus, CST and coticobulbar tracts, abducens nucleus

66
Q

Tracts in the pons that could be affected if anything happened to AICA

A

Lateral pons

  • STT
  • descending sympathetics
  • Spinal trigeminal nucleus and tract (V)
  • Facial nucleus and nerve fascicles (CN 7)
  • Middle cerebellar peduncle
67
Q

Horner’s syndrome

A

Strong pupillary constriction (only parasympathetic fibers are working)and drooping of eye lid, decreased sweating (anhidrosis), increased skin temperature, flushing of skin.

  • Descending from hypothalamus
  • goes through midbrain and pons (AICA)
  • intermediolateral column = pre ganglion sympathetics fibers that go out to ganglion chain (ACh)
  • Post-sympatic neuron follows arteries and innervates the dilator muscle (ciliary muscle)
68
Q

Occularmotor nerve

A

MOTOR only – GSE: eye muscles except lateral rectus and superior oblique.

Also Innervates levator palpebrae superioris muscle

Comes out in the interpeduncular fossa – this is also where the prepontine cistern is.

Edinger-Westphal nucleus (part of oculotomotor nucleus -GSE) – sphincter pupillage, ciliary muscle (final destination after synapse in parasym. ganglion)

69
Q

Trochlear Nerve

A

motor only–GSE: innervates the superior oblique muscle of the eye (down and out)

Trochear nucleus

70
Q

Lateral motor systems

A

Lateral corticospinal tract: movement of contralateral limbs

Rubiospinal tract - movement of contralateral limbs (humans unknown)

71
Q

Medial motor systems

A

Anterior corticospinal tract: control of bilateral axial and girdle muscles

Vestibulospinal tract: medial VST: Positioning of head and neck; lateral VST =balance

Reticulospinal tracts: automatic posture and gait-related movements

Tectospinal tract: coordination of head and eye movement (uncertain in humans)

72
Q

midbrain– Blood supply and areas they can affect

A

SCA and proximal PCA – superior colliculus

Proximal PCA: lateral to cerebral aqueduct
-Reticular formation, STT, Descending sympathetics, medical lemniscus, red nucleus, substance nigra, pyramidal tract (CST, corticobulbar tracts)

Paremedian branches: affect medial oculomotor nucleus and nerve fascicles. Can affect medical 1/2 of red nucleus.