Brainstem and Cranial Nerves Flashcards
Hating life
where is open and closed medulla?
lower medulla is closed, upper medulla is open.
what does open medulla refer to?
presence of 4th ventricle
characteristic feature of medulla
pyramids (ventral)
characteristic feature of pons
fibers going across (bridge) (ventral)
where are the pyramidal tracts in the pons?
they are embedded in the fibers running laterally, going from cortex to spine
characteristic feature of midbrain
lateral cerebral peduncles (ventral)
cerebral peduncles are…
…massive bundles carrying motor information
how to distinguish lower vs upper pons
upper pons has much smaller ventricular space (dorsal)
what is the only motor nuclei that has two motor neurons in the chain? and what does it do?
GVE. controls glands and smooth muscle
hemiplegia
loss of motor control on one side
only GSA/temp nucleus in the brain
descending trigeminal nucleus
what’s the main SVA modality? from where?
taste, from the epiglottis
hemiparesis
weakness on one side. less severe than hemiplegia
olfactory tract can also be called
olfactory peduncle
scotoma
a little blind spot
what if you lost right optic nerve?
blindness in right eye
what if you lost your right optic tract?
you would lose your left visual field
what if the optic chiasm was severed?
you would lose the outer (temporal) visual fields in both eyes
biggest nerve that controls eye movement?
oculomotor
oculomotor nerve connects to how many of the 6 eye muscles? which?
4/6. medial/superior/inferior rectus, and inferior oblique
trochlear nerve is the only….
…entirely crossed nerve. it only controls the contralateral superior oblique muscle
what does the trochlear nerve do?
controls superior oblique muscle, turns contralateral eye down and medially
medial longitudinal fasciculus carries information about…
…the direction that the eyes should move
nystagmus
the slow/fast eye movement reflex when you’re spinning. like in the subway if you’re watching the tunnel go by? nystagmus direction is the direction of the fast movement
which nerve is not really a nerve?
the optic nerve
cranial nerve I
olfactory (you have one nose)
glomerulus
region in olfactory bulb where olfactory receptors synapse onto second order olfactory neurons
olfactory tract bypasses what (1 answer) on its way where (4 answers)?
reticular formation; piriform cortex, olfactory tubercle, amygdala, entorhinal cortex
cranial nerve II
optic (you have 2 eyes)
optic tract
the name for the fiber tract between the optic chiasm and the LGN; each optic tract contains information from one half of visual field
topography of V1
superior bank of calcarine sulcus represents lower visual field; inferior bank of calcarine sulcus represents upper visual field. information from macula is most posterior
cranial nerve III
oculomotor
GVE function of oculomotor nerve
pupillary constriction, comes from Edinger-Westphal nucleus
cranial nerve IV
trochlear nerve (trochlea means ‘pulley’, you get bullied if you’re cross-eyed)
cranial nerve V
trigeminal nerve
trigeminal nerve functions
three branches, three functions:
1) SVE from trigeminal motor nucleus to chewing muscles
2) GSA pain and temp from face to descending trigeminal nucleus to contralateral VPM
3) GSA fine touch from face to principal sensory nucleus to bilateral VPM
(p.s. very important! three functions are spread across three branches- that’s just a mnemonic!)
cranial nerve VI
abducens (you have 6 abs), GSE to lateral rectus muscle of the eye
cranial nerve VII
facial
innervation pattern of face by facial nerve
SVE from facial motor nucleus to facial expression muscles; lateral part to lower face, intermediate part to upper face
SVA function of facial nerve
taste from anterior 2/3 tongue
cranial nerve VIII
vestibular and auditory (ear sort of looks like an 8)
auditory functions of CN VIII
SSA from spiral ganglion > d. and v. cochlear nuclei > superior olive > inferior colliculus > MGB (thalamus) > A1
topography of cochlea
tonotopic map, base of cochlea prefers higher frequencies, apex prefers lower frequencies
cranial nerve XII
hypoglossal, to ipsilateral tongue
cranial nerve XI
accessory
SVE of accessory nerve
11th nerve, 11 looks like a pair of arms, innervates upper trapezius and neck
what 3-char class is pain/temp?
GSA or GVA
what 3-char class is touch?
GSA
what 3-char class is muscle and joint sent?
GSA
what 3-char class is auditory sense?
SSA
what 3-char class is vestibular sense?
SSA
what 3-char class is pressure/distention/damage?
GVA
what 3-char class is taste?
SVA
what 3-char class is smell?
SVA
what 3-char class is striated muscle motor neurons?
GSE
what 3-char class is preganglionic motor neurons to control glands and smooth muscle?
GVE
what 3-char class is motor neurons for striated muscles of branchiomeric origin?
SVE
what do the GSE fibers in 12-hypoglossal do?
ipsilateral tongue muscles
what does a lesion to GSE 12-hypoglossal cause?
ipsilateral tongue deviation
what do the GSA fibers in 12-hypoglossal carry?
tongue muscle afferents
what do the SVE fibers in 11-accessory do? (2)
flex neck, raise shoulder
what do the GSA fibers in 9-11 carry? (2)
info from eustachian tube, posterior 1/3 of tongue
where do the GSA fibers in 9-11 project to?
descending trigem nucleus
what do the SVA fibers in 9-11 carry?
afferents from inferior ganglion for taste in the posterior 1/3 of tongue, taste from epiglottis
what do the SVE fibers in 9-11 do?
control pharynx/larynx
where do the SVE fibers in 9-11 project from?
nuc ambiguus
what do the SVE fibers in 5-trigeminal do?
chewing muscles
what do the GSA fibers in 5-trigeminal carry?
pain/temp and fine touch
where do pain-temp GSA fibers in 5-trigeminal project to?
descending trigeminal nuc, to contralateral VPM
where do fine touch GSA fibers in 5-trigeminal project to?
principal sensory nucleus of 5, to bilateral VPM
what would hoarseness be caused by?
lesion to SVE in 9-11.
where do the SSA fibers in 8-auditory go?
spiral ganglion to dorsal and ventral cochlear nuclei
what do the medial vs lateral SVE fibers in 7-facial control?
medial controls upper, and lateral controls lower muscles of facial expression
