Exam 3 Flashcards
(160 cards)
1
Q
(T/F) The vestibular system is tonically active.
A
True
2
Q
When kinocilium
A
3
Q
___ is the depolarizing signal in the membranous labyrinth.
A
K+
4
Q
What occurs if hair cells bend toward kinocilium?
A
Further depolarization –> K+ channels open –> Ca+ flow –> NT release increased –> increase signal to vestibulocochlear nerve
5
Q
What occurs if hair cells bend away from kinocilium?
A
Close more K+ channels –> hyperpolarization –> decrease signal to vestibulococheal nerve
6
Q
What is the job of vestibular nucleus?
A
balance activity between both sides
7
Q
Another name for vestibular system
A
special proprioception
8
Q
Fluid within membranous labyrinth
A
enodlymph
9
Q
Fluid upon membranous labyrinth
A
perilymph
10
Q
(Endolymph/Perilymph) is continuous with CSF.
A
perilymph
11
Q
Function of semicircular canals
A
dynamic equilibrium (know how you’re moving)
12
Q
What is the sensory spot in semicircular canals?
A
ampulla
13
Q
What is the sensory spot in the utricle/saccule?
A
macula
14
Q
Macula function
A
static equilibrium (sense pull of gravity)
15
Q
What is the sensory part of the system that generates action potentials through dendrites?
A
hari cells
16
Q
What is cupula? Where is it located?
A
gelatinous membrane
in ampulla
17
Q
Fluid has ____ so ampulla moves through fluid rather than fluid moving toward it (usually).
A
inertia
18
Q
What is the Doll’s Eye Reflex?
A
eyes stay fixed when head moves
19
Q
Vestibulo-Spinal Reflex pathway is a pathway
A
info –> vestibular nuclei –> vestibulospinal tract
20
Q
(T/F) Decussation occurs in the Vestibulo-Spinal Reflex.
A
False!
stays ipsilateral
21
Q
Lateral vestibulospinal tract –>
A
neck + all 4 limbs
22
Q
Ventral vestibulospinal tract –>
A
neck + thoracic limbs
23
Q
What occurs as a result of the vestibulo-spinal reflex?
A
stimulate ipsilateral extensors + dorsal neck (side falling)
inhibit ipsilateral flexors + contralateral extensors
24
Q
What is the purpose of the vestibulo-spinal reflex that is also the main job of vestibular system?
A
oppose gravity
25
Pitch of sound? Loudness of sound?
frequency
amplitude
26
(High/Low) frequencies travel further.
Low
27
Function of ossicles in middle ear
amplify signals
28
Oval/vestibular window adhered to ____ and functions for:
stapes
send pressure waves through perilymph
29
Function of round/cochlear window
relief from fluid pressure
30
Function of middle ear muscles
regular ossicle movement, dampen sound
31
What is the Tensor Tympani M innervated by?
Trigeminal N
32
Function of Tensor Tympani M
stiffen malleus
33
Innervation of Stapedius M
Facial N
34
Function of Stapedius M
stiffens stapes
35
Bony core of cochlea
modiolus
36
3 membranes in cochlea
basilar membrane
reisner's membrane
tectorial membrane
37
Scala vestibuli is filled with ____.
perilymph
38
Cochlear duct is filled with ____.
endolymph (high K+)
39
Scala tympani is filled with ______.
perilymph
40
What two things make up Organ of Corti?
tectorial membrane + hair cells
41
(High/Low) frequencies are perceived at top of cochlea while (High/Low) frequencies are perceived at the base.
low
high
42
Increase in firing rate of hair cells increases ____.
amplitude
43
Order of central processes for vestibular system.
Cochlear N in Cochlear Nucleus --> Trapezoid Body (decussates) --> Caudal Colliculus
44
Function of Caudal commissure
allow bilateral processing of sound (3D map)
45
Doppler Effect
difference in frequency if sound is coming away or toward you
46
Function of thalamus
relay + signal processing
47
Function of medial + lateral geniculate nuclei
receive info from senses --> relay to auditory cortex
48
Location of auditory cortex
sylvian gyrus
49
Function of auditory cortex
high level function / analysis of sounds
50
(T/F) Photoreceptors of the eye are constantly depolarized (tonically active).
True
51
Where are photoreceptors located?
retina
52
Photoreceptors are (inhibitory/excitatory) and release _____ (NT) on ____ cells.
excitatory
glutamate
bipolar cells
53
_____ cells give rise to the Optic N.
ganglion
54
What kind of cell is inhibited at rest in the retina?
ganglion cell
55
Cone function
differentiate between frequencies
produce color vision
56
(Rods/Cones) are high acuity but low sensitivity.
cones
57
What is area centralis?
area of highest cone concentration
highest acuity
center of visual field
58
What 3 types of animals have 3 pigments to detect 3 wavelengths (blue, green, red)?
primates, reptiles, amphibians
59
What 2 animals have 2 pigments and can detect 2 wavelengths (blue, red)?
dog
cat
60
What type of animal has 4-5 pigments into the ultraviolet range?
birds
61
What is the fifth pigment that birds have?
cryptochrome I
62
Function of cryptochrome I
detect magnetic field of earth
(in birds + dogs)
63
Rods function
vision in low light
64
What is the photoreceptor 3 cell pathway?
rod/cone --> bipolar cells --> ganglion cell
65
(Rods/Cones) have high sensitivity but low acuity.
rods
66
What is the highly reflective layer on back of retina
Tapetum Lucidum
67
Function of Tapetum Lucidum
increase sensitivity to light (increase changes of signal to rod)
68
Mechanism of Pupillary-Light Reflex
light --> pre-tectal nuclei --> PSNS split --> CN III --> ciliary ganglia = both pupils constrict
69
In birds, (everything/nothing) decussates so ______ occurs with their PLR response.
everything
only one eye constricts
70
What are photopigments (opsins)?
membrane plates in photoreceptors
71
Red-colored pigment in rods
rhodopsin
72
Rhodopsin mechanism at rest
cGMP activated --> Na+ channel open = constant depolarization
73
Rhodopsin mechanism with photon present
shut off rhodopsin = hyperpolarization --> shut off bipolar cell (inhibitory) --> ganglion cell release from inhibition = AT in Optic N
74
Vitamin A function
reactivates photopigments (back to resting state)
75
Two types of inhibitory interneurons
horizontal cells
amacrine cells
76
Central Processing Vision Mechanism
signal --> Optic N --> Optic chiasm --> Optic tracts --> Lateral geniculate nucleus --> Thalamus --> Visual/Occipital cortex
77
What 3 parts of vision does the Retina process?
color
edge
movement
78
What part of vision is processed higher in the brain?
shape --> ID & location
79
What is parallel processing?
vision can involve emotion + autonomic systems
80
What is stereoscopic vision?
overlap in visual field which allow for depth perception
81
How much decussation do optic tracts have in cat/human? Dog? Bird?
50%
75%
100%
82
Which animal has a narrower stereoscopic field?
dog
83
Cat's eyes are positioned _____, which cause a (smaller/larger) visual field and a (smaller/larger) stereoscopic field.
frontal
smaller
larger
84
Horse/cow eyes are positioned ____, which cause a (smaller/larger) visual field and a (smaller/larger) stereoscopic field.
lateral
larger
smaller
85
In bright light, the (SNS/PSNS) is activated, the ______ M is activated, and the pupil (constricts/dilates).
PSNS
sphincter M
constricts
86
In dim light, the (PSNS/SNS) is decreased, _____ M contracts, which leads to pupil (constriction/dilation).
PSNS
dilator Mm
dilation
87
Pathway of SNS innervation to eye
Brain --> spinal cord (T1-T2) --> vagosympathetic trunk --> synapse at cranial cervical ganglion --> ophthalmic V --> pupil
88
Horner's Syndrome symptoms
constricted pupil, elevated third eyelid, droopy eye, eye sunken in
89
Anisocoria
unequal pupils
90
2 types of anisocoria
miosis
mydriasis
91
Miosis loss of (PSNS/SNS) & (small/large) pupil.
SNS loss
small
92
Mydriasis loss of (PSNS/SNS) & (small/large) pupil.
PSNS
large
93
(T/F) Rods converge on single ganglion cell.
True
Increased sensitivity (but decreases acuity)
94
Cones are (more/less) convergent than rods.
LESS
more 1:1 cones to ganglion cell
greater acuity, less sensitivity
95
Horizontal cell function
lateral inhibition --> sharpens signal
96
Amacrine cell function
signal processing at retinal level
97
Signals to retina on medial side (decussate/don't decussate) while signals on the lateral side of the contralateral eye (decussate/don't decussate).
decussate
don't decussate
98
20% of the optic N goes to the _____.
rostral colliculi
99
Stereoscopy
visual system compares differences between R vs. L side
100
Suprachiasmatic nucleus function
circadian rhythm / hibernation
101
(T/F) The nerves decussate in the vision pathway.
FALSE!
info decussates, not nerves
102
Menace response pathway
optic N --> occipital cortex --> thalamus --> frontal cortex --> cerebellum --> facial N
103
Peripheral Blindness (3 possible problems)
retina
optic nerves
chiasm
104
PLR is affected in (peripheral/central) blindness.
peripheral vision
105
Location of Central Blindness (3)
optic tracts
thalamus
cortex
106
PLR not affected in (peripheral/central) blindness.
central
107
Afferent lesion will (have/not have) anisocoria).
NOT
108
ERG measures:
changes in electrical potential
whether or not retina is functional
109
Bilateral blindness what would it mean to tracking/menace responses & PLR?
NO tracking
NO menace
NO PLR either eye
110
Solanacia family plants block the (SNS/PSNS) function, leading to (dilation/constriction) of pupil.
PSNS
dilation
111
3 possible causes of unilateral central blindness
tumor
stroke
infection
(localized damage)
112
Hemineglect
sensory pathways intact but no behavioral response to stimuli
113
EEG function
access animal's state of consciousness (asleep vs. awake)
measures frequency of brainwaves
114
RAS (Reticular Activating System)
motivation + wakefulness
115
4 states of consciousness
sleep/wake
pathological (epilepsy, meningitis)
pharmacological (drugs)
non-pharm (meditation, music)
116
Coma/stupor
not responsive at all to environment
117
EEG stands for
electroencephalogram
118
EEG of low voltage, high frequency, desynchronized = (what 2 states)
awake
REM sleep
119
EEG of high voltage, low frequency, synchronized =
NREM sleep
120
State of CNS readiness when animal wakes up:
arousal
121
Least muscle tone in ______
REM sleep
122
Arousal (wake) characteristics
behavioral
ANS
neurophysiological (Reticular Activating System)
123
SNS increases during (sleep/wake).
wake
124
2 RAS neurons that act through thalamus
lateral dorsal tegmentum
pedunculopontine tegmentum
125
RAS neurons that BYPASS thalamus (name 3).
NE neurons
serotonin neurons
OREXIN
126
Which NT is proponent of wakefulness & REM sleep?
Acetylcholine
127
Remove RAS =
loss of desynchronized EEG
increase sleep
128
Narcolepsy is due to a loss of ______ in the brain.
orexin
129
Cell bodies for NE neurons located:
locus coeruleus (pons)
130
Cell bodies for Serotonin located:
midbrain/pons (raphe)
131
(high/low) activity of NE/serotonin during wakefulness, and ____ during REM sleep.
high
OFF
132
REM sleep has ____ waves which generated visual aspect of it.
PGO
133
What NT is released to inhibit alpha motor neurons for muscle atonia in REM sleep?
GABA
134
What state does cardiorespiratory control get destabilized?
REM sleep
135
High ____ power with high voltage in EEG.
delta
136
What is slow wave sleep initiated by?
GABAergic VLPO neurons (ventrolateral preoptic)
137
What are 2 humoral agent that can induce slow wave sleep?
adenosine (normally)
pro-inflammatory cytokines (sickness)
138
Humoral mediator that allow pregnant moms to have more REM sleep:
prolactin
139
Wakefulness (VLPO & RAS)
up RAS
inhibits VLPO
140
Sleep (VLPO & RAS)
down RAS
up VLPO
141
(T/F) A comatose animal can still have reflexes.
True
142
Modified Glasgow Coma Scale
1-3
3 is lowest
greatest state of coma/unconsciousness
143
Anesthesia (on RAS, respiration, EEG)
RAS - down
resp - down
EEG - synchronized
144
What is the major receptor acted on with anesthesia?
GABA-a receptor
145
Seizure def
brain disease from cerebral cortex
with abnormal electrical activity
146
Cause of seizures
too many neurons firing synchronously
147
2 things that determine seizure threshold
normal resting membrane potential
balanced input (excite/inhibition)
148
Sz causes
energy deficiency
149
Explain energy deficiency cause of sz
loss of Na/K pump causes Na+ leakage --> depolarization = seziure
150
Myokymia
involuntary muscle spasms
151
Function of astrocytes
take up and buffer extracellular K+ to even out ion concentrations
152
What NT allows for excitation?
glutamate
153
2 possible toxins that are glutamate agonists
myco-toxins
shellfish toxins
154
2 effects of excitotoxicity
cytotoxic edema
apoptosis
155
What part of the brain is particularly susceptible to seizures?
hippocampus
156
Focal seizures
manifest in one specific area
157
2 problems with activating Na+ channels
pyrethrins
mycotoxins
158
What ion is used to regulate Na+ channel?
calcium
159
Lack of calcium binding to Na+ channels will threshold of resting Vm to (increase/decrease).
decrease
160
What is the major inhibitory NT? What channel does it open?
GABA
Cl- channels
