Unit II Flashcards
(107 cards)
1
Q
Cranial Nerve 0
A
chemoreceptors
2
Q
Cranial Nerve I olfactory
A
one of oldest, by passes thalamus and goes to olfactory cortex first then thalamus
3
Q
Where is CN 0 and CN I in the brain?
A
Telencephalon
4
Q
Where is CN II in the brain?
A
Diencephalon
5
Q
Where is CN III-XII except XI in the brain?
A
Middy
pons
medulla
rule of 4
6
Q
Cranial nuggets (4 of them)
A
axons form CN nerve
all CN motor nerve=LMN
corticobular directly innervate CN V, VII, XI, XII
all CN have bilateral innervation except VII, XII
7
Q
All cranial nerves have .. .?
A
2 nuclei
2 nerves
ipsilateral innervation except trochlear nerve (contralateral)
8
Q
Nucleus of origin vs destination
A
cell body of fibers that make nerve
2nd order neuron for incoming sensory info
9
Q
Brain stem lesion, ipsilateral vs contralateral
A
ipsilateral: cerebellar and cranial nerves
contralateral: corticospinal and dorsal column
10
Q
Vision in general
A
only sensory system that provides accurate spatial info from a far
taste/touch=accurate but no distance
smell/hearing=distance but not accurate
11
Q
Electromag spectrum
A
vision only encompasses small part of it
light is unidimentional, straight, and travels far=good for accurate distant sensory
12
Q
LIght interaction with medium
A
refraction- light is bent and slowed
diffraction- light bounces around the object
absorption
13
Q
Wavelength and frequency
A
inversely related
long wavelength, short frequency= decreased energy
short wavelength, inc frequency= increased energy
14
Q
What determines saturation, brightness, color/hue
A
Wavelength= color/hue
amp= brightness
purity=saturation
15
Q
eye anatomy
A
Outer: sclera/cornea
Intermediate:
ant chamber: behind cornea, front of iris/ciliary body
post chamber: behind iris/ciliary body, front of lens
inner: retina
16
Q
Optical disk
A
blind spot, BV=no receptor there
17
Q
Formation of image
A
flipped upside down and backward
18
Q
Cells of retina
A
ganglion cell layer
bipolar layer
photoreceptor
amacrine/horizontal layer (lateral interneurons)
19
Q
Lateral interneuron cells
A
inhibitory in the periphery
on ganglion cells vs off ganglion cells
20
Q
Rods vs Cones
A
rods: respond to all wavelengths of light max sensitivity at 500nM 1 photoreceptor (rhodopsin) light sensitive for night vision in low light setting less photon needed to elicit response thus daytime bleaches rods
cones:
responds to only certain wavelengths
blue, green, red, respond to 420,530,650 nM
3 photo receptors (iodopsin)
not light sensitive
for daytime vision (no cones=legally blind)
needs >100 photon to elicit response
21
Q
Retinal conversion
A
only 1 million ganglion cells, over 94 rods/cones
rods:
high convergence=undetail
1 ganglion receives input from many rods
inc light gathering during night low light condition
inhibit spatial resolution (large receptive field)
no rods in fovea
cones:
low convergence=detailed
1:1 ganglion:cone
for acuity
spatial resolution (small receptive field)
almost all cones in fovea, few cones scattered too
22
Q
Rods/Cones firing AP?
A
they don’t fire AP
fire graded potentials (decay in time/space), (don’t have enough sodium channels)
23
Q
Ganglion cells in general
A
first cell in vision pathway to fire AP
axons of ganglion cell form optic nerve
projects to: LGN of thalamus, superior colliculus (retinofugal pathway), brainstem nuclei, suprachiasm nucleus of hypothalamus
24
Q
Parasol vs Midget Cells
A
Parasol cells: monochromatic large cell bodies/receptive field gross movement of stimulus large fibers to LGN magnocellular layer (4cA)
Midget cells: numerous small cell bodies/receptive fields fine detailed/color small fibers to LGN parvocellular layer (4cB)
25
Normal path for visual perception
retina eye to LGN of thalamus to Visual cortex
info is divided at chiasm
shared at splenium
26
2 streams of info of vision
dorsal: tells us where
ventral: tells us what
27
Visual field affected by lesion
```
Optic nerve
Optic chiasm
Optic tract
Lower bank/meyer's loop
Upper bank/optic radiation
```
28
Most common eye symptom
double vision
other eye movement controlled by tectum
29
Intrinsic eye movement
```
iris spincter (parasymp of CN III)
pupillary dilator (ascending cervical sympth)
ciliary body (parasymp of CN III)
```
Vision of near object: ciliary body relaxes
Vision of far object : ciliary body contracts (bends lens to converge the divering light rays)
Dim light: pupillary dilator contract, iris sphinctor relax
Bright light: pupillary dilator relax, iris sphinctor contract
30
Extrinsic eye movement
Superior oblique- introsion- CN IV
Inferior oblique- extorsion- CN III
Superior/Inf/Medial rectus- CN III
Lateral rectus- CN VI
31
Oculomotor CN III autonomic vs somatic control
autonomic- iris sphinctor- edinger westphal nuclues
somatic- al lthe recti except lateral, inferior oblique, and levator palpebrae (central caudal nucleus)
32
CN III lesion
impaired eye movements- extraocular mm
droopy eyelids- ptosis levator mm
pupilary dilation- iris sphinctor
33
CN VI nucleus and CN VII form. . .
facial colliculus at the base of 4th ventricle
34
Where is CN IV nucleus
dorsal caudal midbrain
35
CN V1 ophthalmic function
mostly sensory
skin: sensory of forehead, eyelid, eyebrow
orbit: eyeball, lacrimal gland, conjunctiva, nasal cavity
36
CN V2 maxillary function
sensory
lower eyelid, nose, cheek, part of pharynx, upper teeth, lips, gums
37
CN V3 mandibular function
sensory and motor
sensory: lower lips, gum, teeth, pharynx, ant 2/3 of tongue
motor: tensory tympani, muscle of mastication
38
CN VII function
sensory: taste of ant 2/3 of tongue, outer ear
motor: facial expression, lacrimation/salivation, stapedius
39
CN VIII function
hearing
| equilibrium
40
semilunar ganglion project to which 3 Nucleus of destination of V?
mesencephalic, chief trigeminal sensory, spinal trigeminal
41
Mesencephalic trigeminal nucleus
Aalpha fibers, propio jaw reflex
bypasses the semilunar ganglion and possess the mesencephalic nucleus within the CNS (only exception)
synapses onto nearby motor nucleus of V
42
Chief trigeminal nucleus
Abeta fibers, discrimintive touch
semilunar ganglion synapses onto the chief trigeminal nucleus at the pons level
second order neuron crosses and continues up with the Medial lemniscus tract towards VPM of thalamus for sensory touch
43
Spinal trigeminal nucleus
Adelta c fibers, pain/pressure/temp
semilunar ganglion dives down to caudal medulla continuous with C1-C2 level and synapses with spinal trigeminal nucleus
second order neuron crosses and continues up with the spinothalamic tract towards VPM of thalamus for pain sensation
44
Other CN also send input to spinal trigeminal nucleus
CN VII, IX, X
45
CN VII sensory cell bodies are?
geniculate nucleus
46
CN VII Upper face
input to dorsal division of VII nucleus, bilateral innervation
47
CN VII Lower face
input to ventral division of VII nucleus, contralateral innervation
48
CN VII UMN lesion
can still wrinkle forehead, lower face below eyes is paralyzed
49
CN VII LMN lesion
whole side of face is paralyzed
50
CN VII nuclei of destination
pons (motor): facial nucleus, salivatory nucleus
medulla (sensory): nucleus solitarius (receives axons from DRG in geniculate
51
CN VIII hearing and equilibrium
spiral ganglion in the cochlear projects to dorsal/ventral cochlear nuclei in pons/medulla (cross many times, lesion=not clinically relevant)
vestibular ganglion in otolith/SSC project to vestibular nuclei
52
CN IX & X in general
rule of 4
function: pharyngeal, laryngeal muscle, neck, tongue, dysarthria, dysphagia
bilateral neuromotor signs =ALS
53
CX IX & X both
connect to shared nuclei:
VII nucleus solitarius, V trigeminal, X nucleus ambiguus
superior and inferior ganglia (jugular foramen)
54
CN IX anatomy
between the inferior olive and inferior cerebellar peduncles just below CN VIII at the pontomedullary junction
55
CN IX motor
stylopharyngeus, origin: nucleus ambiguus
parasympathetic inn. of parotid glands, origin: inferior salivatory nuclei
56
CN IX sensory
somatosensation: middle->external ear, pharynx, post 1/3 of tongue, origin trigeminal nuclei
taste: posterior 1/3 of tongue, origin: rostral nucleus solitarius, VII, X
chemo/baroreceptor of carotid body, origin: caudal nucleus solitarius X
57
CN IX gag reflex
touch/taste to back of tongue
contraction by CN X
stronger reflex <6months, begins diminishes 6-7 months
58
CN IX lesion signs (rare)
```
dysphagia
dysfunction of parotid gland
dec somatosensation of middle->external ear
bitter taste of post 1/3 of tongue
brachycardia, tachycardia
absent gag reflex
```
59
CN X in general
longest course of CN, 80-90% of fibers for sensory viscera
for swallowing, gag, taste phonation, passes through jugular foramen
multifunction=often implicated in lesions, joints the cranial part of CNXI below the inferior ganglia
60
CN X motor
pharyngeus and laryngeus muscles (except stylopharyngeus) origin: nucleus ambiguus
parasympathetic inn. of heart, bronchi, GI-splenic flexure, Origin: dorsal motor nucleus of X
61
CN X sensory
somatosensation of small region of posterior external accoustic meatus, pharynx, meninges, Origin: trigeminal nuclei
taste: epiglottis and pharynx
chemo/baroreceptor: aortic arch
62
CN X lesion (rare)
paralysis of palate, pharynx, larynx
| leads to hoarseness, dysphagia, choking, dec gag reflex, ineffective cough
63
CN X lesion autonomic signs
soft palate lack of elevation
deviation of uvula to opposite side of lesion
abnormalities of: esophogeal mobility, gastic acid secretion, gallbladder emptying, heart rate
64
CN X laryngeal recurrent signs
unilateral: dysphonia
bilateral: aphonia, obstruction of airway, stridor
65
Testing CN IX and X
test in conjunction
```
say ah (uvula midline, soft palate elevation)
voice quality (hoarseness, dysarthria)
gag
swallowing
bitter taste
```
66
Reticular formation in anatomy
spans from top of cord to caudal diencephalon
core of brain stem tegmentum
67
Historical view of RF
mesencephalic transection: spontaneous breathing, hypersomnia, pupillary abnormality
cord transection: sleep-wake cycle (tho altered), normal EEG, normal pupillary dilation
68
Modern view of RF
3 columns
lateral: 1/3 of RF, parvocellular, afferent sensory
medial/medin raphe: 2/3 or RF, efferent to regulate CNS wide spread
Midbrain RF: awake, arousal, attention
Pontine RF: respiratory nuclei, activate neocortex during REM (AcH release)
Medulla RF: spinal motor neurons (vomit/respiratory/reflex/vasomotor (BP HR)), inhibition for near total body paralysis during REM sleep
69
Reticular formation in general
lay outside of the major tracts, have polysynaptic connections
receives sensory input from all except DC-ML, efferent to all levels of CNS
affects responsiveness of cortex, motor/sensory/autonomic
70
Reticular Formation Nuclei
precise locations of nuclei (NOT net like) with known projections pattern and neurotransmitters
several CN nuclei lay in the RF
71
RF efferent projections
```
short projections (lateral 1/3 of RF)
long projections (median/medial 2/3 of RF)- long ascending fibers that synapse via collaterals with long descending fibers, bifurcating neuron that ascends and descends
```
72
RF organization
Rostral: continues with diencephalon, upper pons, mesencephalon and regulates alertness/consciousness in forebrain
Caudal: continues with intermediate zone of SC, lower pons, medual, collaborates with SC/CN for motor reflexes and autonomic functions
73
RF Consciousness system
Cortical: medial and lateral frontalparietal association cortices
subcortical: diencephalon and upperbrainstem
74
RF Consciousness system: Subcortical
forebrain innervated by upper pons, middy,
brainstem/cerebellar/sc innervated by lower brainstem
75
Consciousness 2 principle function
content of consciousness
| level of consciousness
76
Content of consciousness
comprised of systems that regulate sensory,motor,memory,emotional function
when conscious system acts, brainstem system provides substrate
77
Level of consciousness
regulated by consciousness system
maintenance of wakeful/arousal
alertness/attention/awareness
78
Alertness
regualted by diencephalon, upper pons, cortex
if lesion=coma
79
Attention
same as alertness with addtion of frontalparietal association cortices
80
Awareness
un as well understood
| integrates sensory input for unified summary of current mental activity
81
Acending Reticular activating system
maintenance of consciousness requires multiple sytems of ARAS
not all are ascending
not all originate from RF
82
Brain lesions that lead to coma
Upper brain stem lesion (not ventral pons/middy, medulla)
bilateral extensive lesion to thalamus, or cortex
MI, Strangulation, Drowning
83
Subcortical arousal system: upperbrain stem neurons
5-HT, NE, Dopamine project -->cortical/subcortical structures
AcH/pontomesencephalic neurons with Glu project -->thalamus, hypothalamus, basal forebrain
84
Subcortical arousal system: posterior hypothalum neurons
orexin,histamine project --> cortical subcortical structures
basal forebrain containing AcH/thalamic structures containing Glu project to --> cerebral cortex
85
Cholinergic Projections
Cell bodies: nucleus basalis of meynart, pontomesencephalic, brainstem
```
arousal
selective attention
learning/memory
arousal input to the thalamus
facilitating input from forebrain to cortex
```
86
Noradrenergic projections
Cell bodies: locus coeruleus, lateral tegmentum
```
arousal
selective attention
sleep (active during wake, quiet during REM)
sensory input especially pain
autonomic function (BP/HR)
```
87
Seratonin projections
Cell bodies: rostral/caudal raphe
```
arousal
selective attention
sleep
sensory input espeically pain
reticulospinal tract, tone regulation
```
88
Dopamine projections
Cell bodies: mesolimbic, meso striatum, mesocortical
motivation, fear learning, cortical/executive functioning
regulate direct/indirect movement pathways
89
Histamine
Cell bodies: tuberomamillary nuclei, posterior 1/3 of hypothalamus
arousal
sleep
energy balance
learning and memory
90
Brain dead vs coma vs pvs vs minimally conscious vs etc
Brain dead, all absent
coma, spinal and brain stem reflexes
severely depressed cortical purposeful response to stim/arousal sleep wake cycle
PVS, spinal and brain stem reflex
sleep-wake cycle apparent, severely depressed cortical purposeful response to stim
minimally conscious or better, spinal and brain stem reflex, sleep wake cycle apparent, at times some purposeful respone to stim
akinetic/catatonia affects frontal cortex
locked in affects basilar pons, lack of purposeful movement
91
Primary goal of vestibular system
spatial and motion orientation of head
adjust muscle activity of neck and legs to maintain posture
when head moves, stabilize fixed point to create stable image for retina
92
Vestibular where am I going
otolith (saccules/utricles)
| translational/linear
93
Vestibular which way is up
```
semicircular canals (lateral/anterior/posterior SCC)
angular/rotational
```
94
Peripheral apparatus of vestib
detection of linear/angular velocity
relays to central system
95
Central system of vestib
integrates info from many systems a bout position/movement of head
96
Motor out put system of vestib
orients head with respect to gravity
generates eye/head/limb adjustments
97
For Erect posture . .
central vestib system signals about head movement and postural system to result in head/limb stabilization
in conjunction with eye system allows erect posture
98
Common similarities of Auditory and Vestib system
common fluid system (bony and membranous lab)
mechano receptors low Hz-balance high Hz-hearing
shared CN VIII, tumor may affect hearing and balance
99
Otolith receptors are called?
maculae
100
SCC receptors are called
ampullae crista
x axis - pitch
y axis - yaw
z- axis - roll
101
4 vestibular nuclei and its projection
medial, lateral, superior, inferior (dorsal surface of midbrain)
all overlap with info and project to:
SC, Cerebellum, thalamus, RF, oculomotor
102
vestibular path way
scrapas ganglion-->vestibular nuclei and cerebellum -->
MLF, and vestibulospinal tract (medial and lateral)
103
Medial Longitudinal Fasciculus
ascending axons from vestibular nuclei
terminating on nuclei III, IV, VI for adusting eye movements
104
Medial vs Lateral Vestibulospinal tract
```
medial:
orginate: medial vestib. nuclei
terminate: c-spine
adjusts proximal mm. neck
detection of rotational with SCC
```
```
lateral:
originate: lateral vestib. nuclei
terminate: all levels of cord
adjust leg mm for standing
detection of linear with otolith
```
105
Vestibular signals to Cortex
```
Frontal eyefield
somatosensory areas
Parietal insular vestibular cortex
Posterior parietal cortex
hippocampus
```
106
Vestibulo-cerebellum
afferent from flocconodular nodes
| vestib nuclei-->inferior cerebellar peduncles
107
Vestibular signs and symptoms
```
dizziness
vertigo
oscillopsia
light headness
impaired hearing and tinnitus
```
