Brainstem III

Question 1

trochlear nerve: innervates what mm?

Answer 1

superior oblique muscle

Question 2

trochlear nerve to superior oblique mm: what nucleus?

Answer 2

trochlear nucleus to contralateral SO mm

Question 3

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

Answer 3

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

Question 4

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

Answer 4

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

Question 5

signs of lesions of trochlear nerve/nucleus

Answer 5

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

Question 6

possible causes of trochlear lesion

Answer 6

trauma, hydrocephalus, hemorrhage, infarct.

Question 7

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

Answer 7

bilateral SO problem

Question 8

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

Answer 8

ipsilateral

Question 9

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

Answer 9

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

Question 10

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

Answer 10

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

Question 11

symptoms of oculomotor palsy; common clinical cause?

Answer 11

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

Question 12

difference between Horner’s syndrome and an oculomotor nerve lesion

Answer 12

Horners: SYMPATHETICS lost: partial ptosis, miosis, anhydrosis

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

Question 13

CNs with parasympathetic function

Answer 13

3, 7, 9

Question 14

function of posterior commissure of midbrain

Answer 14

pupillary light reflexes

Question 15

periaqueductal grey function

Answer 15

pain

Question 16

function of substantia nigra of midbrain

Answer 16

dopamine, motor system

Question 17

function of ventral tegmental area of midbrain

Answer 17

dopamine, limbic system

Question 18

function of lateral lemniscus of the midbrain

Answer 18

hearing

Question 19

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

Answer 19

retinal ganglion cells to lateral geniculate body in the thalamus

Question 20

*what cells myelinate the optic nerve?

Answer 20

oligodendroglia

Question 21

what CNs do the pupillary light reflex?

Answer 21

II and III

Question 22

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

Answer 22

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

Question 23

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

Answer 23

telencephalon; bipolar neurons olfactory epithelium to the olfactory bulb!

Question 24

unique property of olfactory nerve; an olfactory hallucination

Answer 24

it can regenerate; smell of burning rubber

Question 25

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

Answer 25

proprioceptive fibers to mesencephalic nucleus of V

Question 26

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

Answer 26

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

Question 27

structures supplied by the anterior cerebral artery

Answer 27

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

Question 28

structures supplied by the posterior cerebral artery

Answer 28

oculomotor nucleus, edinger-westphal, trochlear nucleus

Question 29

structures supplied by AICA

Answer 29

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

Question 30

structures supplied by pica

Answer 30

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

Question 31

structures supplied by anterior spinal artery

Answer 31

accessory nucleus, hypoglossal nucleus

Question 32

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

Answer 32

Raymond's Syndrome Millard-Gubler Syndrome

Question 33

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

Answer 33

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

Question 34

what cranial nerve is involved in a ventral pons lesion?

Answer 34

CN VI

Question 35

what cranial nerve is involved in a middle pons lesion?

Answer 35

CN VII

Question 36

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

Answer 36

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

Question 37

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

Answer 37

Weber's syndrome; contralateral hemiparesis, ipsilateral ocular paresis

Question 38

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

Answer 38

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

Question 39

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

Answer 39

reticular formation

Question 40

functions of reticular formation

Answer 40

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

Question 41

where is the pain suppression system of RF located?

Answer 41

nucleus raphe magnus in pons

Question 42

where is the autonomic reflexes of RF located?

Answer 42

respiratory center-medulla, pons cardiovascular centers- medulla

Question 43

the descending sympathetics of RF descend from..

Answer 43

hypothalamus

Question 44

part of the RF that does arousal and consciousness

Answer 44

ascending reticular activating system (ARAS)

Question 45

part of RF that does posture

Answer 45

reticulospinal tracts

Question 46

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

Answer 46

median zone: raphe nuclei medial zone: ascending and descending projections, POSTURE TRACTS, medullary and pontine reticulospinal tracts lateral zone: CN reflexes and visceral functions

Question 47

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

Answer 47

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

Question 48

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

Answer 48

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

Question 49

function, location of serotonin (5-HT)

Answer 49

arousal, pain control; raphe nuclei

Question 50

functions, locations of acetylcholine

Answer 50

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

Question 51

function of antipsychotics

Answer 51

block dopamine receptors in ventral tegmental area (VTA)

Question 52

function of antidepressants

Answer 52

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

Question 53

replacement therapy for alzheimer's and Parkinson's patients

Answer 53

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