Brainstem III Flashcards

1
Q

trochlear nerve: innervates what mm?

A

superior oblique muscle

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2
Q

trochlear nerve to superior oblique mm: what nucleus?

A

trochlear nucleus to contralateral SO mm

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3
Q

where does the trochlear nerve decussate? where does it exit?

A

superior medullary velum; exits dorsally to subarachnoid space, cavernous sinus, superior orbital fissure into the orbit to SO

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4
Q

SO paralyzation is contralateral or ipsilateral if the trochlear nucleus is damaged?

A

contralateral. if trochlear nerve is damaged after decussation its ipsilateral.

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5
Q

signs of lesions of trochlear nerve/nucleus

A

can’t look down and in (extorsion), vertical diplopia when reading/walking down stairs, head tilt + chin down contralaterally to affected SO

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6
Q

possible causes of trochlear lesion

A

trauma, hydrocephalus, hemorrhage, infarct.

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7
Q

if the trochlear nerve is damaged at decussation, will the signs be contralateral or ipsilateral?

A

bilateral SO problem

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8
Q

if the trochlear nerve is damaged after decussation, is the sign ipsilateral or contralateral?

A

ipsilateral

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9
Q

oculomotor nerve- somatic motor function: which nucleus? to which muscles?

A

oculomotor nucleus; to levator palpebrae superioris, extrinsic eye muscles except LR6SO4

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10
Q

oculomotor nerve- visceral motor function: which nucleus? to which structures?

A

nucleus of Edinger-Westphal- parasympathetics to ciliary ganglion on to pupillary constrictor and ciliary body

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11
Q

symptoms of oculomotor palsy; common clinical cause?

A

down and out mydriasis (pupil dilation), full ptosis; posterior cerebral artery stroke

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12
Q

difference between Horner’s syndrome and an oculomotor nerve lesion

A

Horners: SYMPATHETICS lost: partial ptosis, miosis, anhydrosis

CN III: SOMATIC MOTOR LOST: full ptosis, down and out, PARASYMPATHETICS LOST: mydriasis (dilated pupil)

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13
Q

CNs with parasympathetic function

A

3, 7, 9

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14
Q

function of posterior commissure of midbrain

A

pupillary light reflexes

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15
Q

periaqueductal grey function

A

pain

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16
Q

function of substantia nigra of midbrain

A

dopamine, motor system

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17
Q

function of ventral tegmental area of midbrain

A

dopamine, limbic system

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18
Q

function of lateral lemniscus of the midbrain

A

hearing

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19
Q

the optic nerve special somatic sensory: what ganglion? to what structure in the brain?

A

retinal ganglion cells to lateral geniculate body in the thalamus

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20
Q

*what cells myelinate the optic nerve?

A

oligodendroglia

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21
Q

what CNs do the pupillary light reflex?

A

II and III

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22
Q

pathway of pupillary light reflex, and reason why both eyes will blink

A

sensory via optic nerve to the pretectal nucleus in the midbrain, synapses with interneuron that bilaterally innervates oculomotor nerve on both sides via the Edinger-Westphal nucelus

23
Q

what part of the brain is the olfactory nerve located in? what cells do special visceral sensory of olfactory nerve travel on?

A

telencephalon; bipolar neurons olfactory epithelium to the olfactory bulb!

24
Q

unique property of olfactory nerve; an olfactory hallucination

A

it can regenerate; smell of burning rubber

25
Q

what fibers are the sensory component of motor cranial nerves III, IV, VI, XII? to what nucleus do they go through?

A

proprioceptive fibers to mesencephalic nucleus of V

26
Q

CNs 7, 9, 10, 1 for taste and olfactory (special visceral sensory) go through which nucleus?

A

solitary nucleus, along with 9, 10 for internal organs general visceral sensory

27
Q

structures supplied by the anterior cerebral artery

A

olfactory nerves, olfactory bulb and tract, optic chiasm, optic nerve, optic tract

28
Q

structures supplied by the posterior cerebral artery

A

oculomotor nucleus, edinger-westphal, trochlear nucleus

29
Q

structures supplied by AICA

A

motor nucleus, chief sensory nucleus, trigeminal nerve, abducens nerve, facial nucleus, superior salivatory nucleus, facial nerve

30
Q

structures supplied by pica

A

cochlear nuclei, vestibular nuclei, all components of glossopharyngeal, nucleus ambiguous, vagus nerve

31
Q

structures supplied by anterior spinal artery

A

accessory nucleus, hypoglossal nucleus

32
Q

syndrome caused by lesion to the ventral pons; syndrome caused by lesion to the middle pons

A

Raymond’s Syndrome

Millard-Gubler Syndrome

33
Q

syndrome caused by lesion to the dorsal pons; what structures are involved?

A

Foville’s syndrome: nuclei VI (MLF) and VII, CN VII

34
Q

what cranial nerve is involved in a ventral pons lesion?

A

CN VI

35
Q

what cranial nerve is involved in a middle pons lesion?

A

CN VII

36
Q

what lesion/name is given to the locked in syndrome? symptoms?

A

dorsal pons lesion (Foville’s syndrome); ipsilateral facial paralysis, loss of conjugate movement on contralateral medial rectus

37
Q

damage to the LCST and CN III in the midbrain causes what syndrome? symptoms?

A

Weber’s syndrome; contralateral hemiparesis, ipsilateral ocular paresis

38
Q

where is the lesion in Parinaud’s syndrome? what are the signs?

A

superior colliculi (midbrain) lesion; paralysis of upward gaze – like paranoid, can’t look upward.

39
Q

the central core of the brainstem, with single neurons of mixed function with multiple inputs and outputs

A

reticular formation

40
Q

functions of reticular formation

A

pain suppression, autonomic reflexes, descending sympathetics, arousal consciousness, posture

41
Q

where is the pain suppression system of RF located?

A

nucleus raphe magnus in pons

42
Q

where is the autonomic reflexes of RF located?

A

respiratory center-medulla, pons

cardiovascular centers- medulla

43
Q

the descending sympathetics of RF descend from..

A

hypothalamus

44
Q

part of the RF that does arousal and consciousness

A

ascending reticular activating system (ARAS)

45
Q

part of RF that does posture

A

reticulospinal tracts

46
Q

the 3 longitudinal zones of the reticular formation, and what is in each of them

A

median zone: raphe nuclei

medial zone: ascending and descending projections, POSTURE TRACTS, medullary and pontine reticulospinal tracts

lateral zone: CN reflexes and visceral functions

47
Q

function, location in the brainstem, nuclei involved with norepinephrine (NE)

A

attention; locus ceruleus in lateral RF, solitary nucleus, dorsal motor nucleus of X

48
Q

function, locations, what happens when its deficient -dopamine (DA)

A

initiation of movement, motivation, cognition; substantia nigra axons to striatum, ventral tegmental area axons to limbic system; schizophrenic hallucinations, dreams, can cause seizures, parkinson’s

49
Q

function, location of serotonin (5-HT)

A

arousal, pain control; raphe nuclei

50
Q

functions, locations of acetylcholine

A

muscarinic receptors in CNS, sleep/wake cycle; reticular formation to thalamus, basal forebrain (nucleus basalis of meynert to cortex, amygdala, hippocampus), striatum interneurons

51
Q

function of antipsychotics

A

block dopamine receptors in ventral tegmental area (VTA)

52
Q

function of antidepressants

A

norepinephrine (lateral column) and serotonin (raphe) receptor alterations, increase levels of dopamine and norepinephrine

53
Q

replacement therapy for alzheimer’s and Parkinson’s patients

A

ACh (nucleus basalis) given to Alz px; dopamine (substantia nigra) given to Parkinson’s px