Unit 2: CNS Sensory Flashcards
1
Q
what does structure determine
A
function
2
Q
what symmetry do humans have
A
bilateral
3
Q
organization of the nervous system
A
4
Q
anterior or rostral
A
front part of a structure
5
Q
posterior or caudal
A
back part of a structure
6
Q
dorsal
A
pointing out of the back
7
Q
ventral
A
pointing towards the ground
8
Q
lateral
A
towards the side
9
Q
medial
A
towards the middle
10
Q
ipsilateral
A
same side of the body
11
Q
contralateral
A
opposite side of the body
12
Q
horizontal
A
a slice parallel to the ground
13
Q
coronal (transverse)
A
a slice vertical from front to back
14
Q
sagittal
A
- a slice perpendicular to the ground
- parallel to the neuraxis
15
Q
hindbrain parts
A
- myelencephalon
- metencephalon
16
Q
myelencephalon
A
- contains medulla oblongata
- contains nuclei that control vital functions (breathing and skeletal muscle tone)
17
Q
metencephalon
A
- the cerebellum: receives information from sensory systems, muscles, and vestibular system; produce smooth movement
- pons: a large bulge on the brain stem involved in sleep and arousal
18
Q
mesencephalon
A
- one of the 3 divisions of the brainstem
- basic physiological function (breathing, swallowing, heart beat)
- gates sensory and motor information
19
Q
red nucleus
A
coordinates sensorimotor information
20
Q
substantia nigra
A
cells make dopamine and project to basal ganglia
21
Q
periaqueductal grey matter
A
involved in pain suppression due to high concentration of endorphins
22
Q
forebrain parts
A
- diencephalon
- telencephalon (cerebrum)
23
Q
diencephalon
A
- thalamus: interconnected nuclei receive information from the sensory systems (except olfactory) and relay information to sensory processing area in the cortex; learning and memory; slow sleep waves generated
- hypothalamus: 22 nuclei and pituitary gland, control the ANS and endocrine system; key aspects of behavior (feeding, sex, sleep, temp. regulation, emotional behavior)
24
Q
telencephalon
A
- hemispheres separated by the longitudinal fissure
- hemispheres connected by the corpus callosum
- grey matter and white matter
25
how much of the cerebrum is hidden in the gyri and sulci
2/3
26
spinal cord function
- neuronal link between PNS and brain
- spinal reflex integration center
27
how many pairs of spinal nerves are there
31
28
dorsal root meaning
afferent sensory
29
ventral root mening
efferent motor
30
phrenology definition
- skull mimicks personality
- larger brain area (ex. forehead) indicates a greater tendency toward the faculty of that area
- not valid as a scientific theory
- first time a specific function was associated with a specific brain region
31
electrical stimulation
- Luigi Rolando (1809)
- provided proof that the CNS was electrically excitable and that brain functions are anatomically localized
32
case of Phineas Gage
- spike went through his skull
- profound personality changes after the accident
- personality improvement in Chile (using social and complex cognitive-motor skills)
33
case of Patient Tan
- diagnosed with epilepsy early in childhood
- admitted to hospital at 21, could only say "tan" twice in a row
- broca coined this disorder aphasia
- good comprehension
- broca reported softening in what would become known as broca's area in a brain examination postmortem
34
who coined the term aphasia
paul broca
35
aphasi
absence of overt speech
36
paul broca patients
- patient tan
- patient lelong
37
case of patient lelong
- reduced productive speech at 84 after a stroke
- could only say 5 words (oui, non, tois, toujours, and lelo)
- lelong had a lesion in the same region as patient tan
38
broca's area
the frontal lobe of the dominant sphere (left for most of righthanded people and half of left handed people)
39
who first described receptive aphasia
carl wernicke
40
receptive aphasia
- impaired comprehension of their own speech
- don't realize their errors
- associated with stroke, trauma, tumor, infections, and degenerative brain disorders
41
wernicke's area
a region of superior temporal gyrus in the dominant cerebral hemisphere
42
types of aphasia
- broca's aphasia
- wernicke's aphasia
- conduction aphasia
43
broca's aphasia
difficulty in production of language
44
receptive aphasia
difficulty in comprehension of language
45
conduction aphasia
- due to damage of arcuate fasciculus
- patients are aware of their mistakes and try to fix them
46
arcuate fasciculus
the bundle of axons that connect broca's area to wernicke's area
47
case of patient h.m.
- hit his head while biking
- intractable epilepsy after the accident (blocking out often, convulsions, could no longer work)
- dr. scoville removed two finger-shaped slivers of tissue from his brain (anterior 2/3 of hippocampi, parahippocampal cortices, entorhinal cortices, piriform cortices, and amygdala)
- seizers stopped but developed severe anterograde amnesia (short term memory intact, no new long-term memories) and retrograde amnesia (could not remember events from 3-4 days before surgery and some events up to 11 years before)
- ability to form long-term procedural memories was intact (could learn new motor skills but not remember learning them)
48
unit of structure of the CNS
neurons
49
neuron - cell membrane
50
neuron - dendrites
51
neuron - cell body (soma)
52
neuron - axon
53
neuron - axon hillock
54
neuron - myelin sheath
55
neuron - node of ranvier
56
neuron - synaptic end bulbs
57
neuron - axon terminal
58
pre- and postsynaptic neurons - presynaptic neuron
59
pre- and postsynaptic neurons - neurotransmitters
60
pre- and postsynaptic neurons - receptors
61
pre- and postsynaptic neurons - postsynaptic neuron
62
pre- and postsynaptic neurons - synaptic cleft
63
pre- and postsynaptic neurons - synaptic vesicles
64
pre- and postsynaptic neurons - axon terminal
65
action potential
electrical signals sent over a long distance
66
a plasma membrane is a ________________ ______________ that is composed of:
- phospholipid bilayer
- phospholipids
- glycolipids
- cholesterol
- membrane protein
67
plasma membrane - extracellular matrix fibers
68
plasma membrane - glycoproteins
69
plasma membrane - carbohydrates
70
plasma membrane - glycolipid
71
plasma membrane - cytoplasm
72
plasma membrane - proteins
73
plasma membrane - cholesterol
74
plasma membrane - phospholipid
75
plasma membrane - cytoskeleton microfilaments
76
plasma membrane - intercellular space
77
phospholipid - hydrophobic tail
78
phospholipid - hydrophilic head
79
is the plasma membrane highly permeable?
no, it is selectively permeable
80
what do plasma membranes allow directly through
- gas (COs, O2, N2, etc.)
- small uncharged polar molecules (ethanol, etc.)
81
what do plasma membranes sometimes allow directly through
water (only in specific conditions)
82
what plasma membranes never allow directly through
- ions (K+, Ca2+, etc.)
- charged polar molecules (amino acids, ATP, etc.)
83
how do ions and charged polar molecules go across a plasma membrane
- simple diffusion
- facilitated diffusion (protein-mediated)
- active transport
84
which channel/carrier proteins are passive and which require energy
passive:
- facilitated diffusion
energy:
- active transport
85
passive transport
down concentration gradient
86
why does active transport require energy
it goes against the concentration gradient
87
electrochemical gradient
combination of concentration and charge differences across the membrane
88
facilitated diffusion
passive, down gradient using a protein channel or carrier
89
channel proteins
selective pore
90
carrier proteins
bind solutes tightly, undergo conformational changes
91
which transport maintains chemical imbalance necessary for life
active transport
92
charge (Q)
net imbalance in the number of positively and negatively charged particles
93
current (I)
- flow of electrically charged particles
- charged particles = ions
94
voltage (V)
- difference in charge between inside and outside of the cell
- represents an electrical potential energy gradient down which particles want to move
95
electrical gradient
- influenced by the overall electrical charge
- positive ions would flow toward negative charge
96
chemical gradient
- influenced by the individual concentration of a particular ion
- all ions move from high to low concentration
97
the direction that an ion moves depends on:
- overall net effect of electrical and chemical (electrochemical) gradients
- membrane permeability to ions (no channels = no movement)
98
how is the electrochemical gradient maintained
Na+-K+ pump
99
Na+-K+ pump
- maintains Na+ and K+ gradients across the plasma membrane
- abundant
- P-type transport ATPase
- phosphorylation changes the conformation of the pump, exposing binding side on the extracellular membrane
- ionic imbalance
100
ionic imbalance importance
- intracellular pH control
- osmotic control
- transport
- excitability
101
how much of a cell's energy foes to powering the Na+-K+ pump
1/3
102
Na+-K+ pump step 1
binding cytoplasmic Na+ stimulates ATP
103
Na+-K+ pump step 2
phosphorylation causes conformational change
104
Na+-K+ pump step 3
Na+ is liberated outside and K+ binding sites are exposed inside
105
Na+-K+ pump step 4
binding K+ triggers the release of the phosphate
106
Na+-K+ pump step 5
release of phosphate restores original conformation
107
Na+-K+ pump step 6
K+ is released and Na+ binding sites are exposed in the cytoplasm
108
equilibrium potential
the electrical potential difference that exactly counterbalances diffusion due to the concentration difference
109
nernst equation
- electrical potential required to oppose the movement of an ion across a permeable membrane
- provides a measure of the chemical driving potential established by the concentration gradient for ion
110
gating definition
transition between conducting and non-conducting (open and closed) states of an ion channel
111
goldman equation
- defines membrane potential
- accounts for relative permeability of the ions
112
which axon was used to determine resting membrane potentials
squid giant axon
113
absolute refractory period
- a period of complete resistance to stimulation
- Na+ channel inactivation means after an action potential there is a brief period when no other action potentials can be generated
114
relative refractory period
- a period of partial resistance to stimulation
- lasts as long as K channels are open
- strong stimulus can trigger a new action potential
115
contiguous conduction
conduction of action potentials in unmyelinated axons
116
conduction speed definition
nerve impulse speed
117
conduction speed number
nerve impulse travels 1 meter in 0.1 seconds
118
c fibers job
carry sensory information
119
are c fibers myelinated
no
120
c fiber damage causes what
neuropathic pain
121
axon potential propagation speed depends on ....
how local currents spread
122
how local currents spread in axon potential propagation speed depends on
- internal resistance of the axon
- resistance of the axonal membrane
123
do narrow axons have high or low internal resistance
high
124
to get a faster axon potential propagation speed the axon could be ....
- wider
- myelinated to increase membrane resistance
125
myelin
a membrane component from glial cells that surrounds and insulates consecutive axon segments
126
saltatory conduction
the way an electrical impulse skips from node to node down the full length of an axon, speeding the arrival of the impulse at the nerve terminal
127
myelinated fibers in the PNS
schwann cells
128
myelinated fibers in the CNS
oligodendrocytes
129
consequence of demyelination
multiple sclerosis (MS)
130
multiple sclerosis
- autoimmune disease
- myelin sheath degenerates and forms hardened scars
- affected axons degenerate
- slowing and block of AP conduction
131
multiple sclerosis risk factors
- age (20-40 years old)
- sex (women)
- family history
- certain infections (Epstein-Barr infection aka mono)
- race (white)
- temperate climate
- vitamin d deficiency
- other autoimmune diseases (thyroid disease, psoriasis, type 1 disease)
- smoking
132
peripheral nervous system function
- sensory systems: detect external and internal stimuli
- higher brain regions: process and integrate different information and make decisions
- motor systems: execute decisions
133
pns
fibers (other than brain and spinal cord) that carry information between CNS and other body parts
134
PNS divisions
- afferent division
- efferent division
135
PNS types of afferent divisions
- visceral afferent
- sensory afferent
136
PNS afferent division
send information from internal and external environment to CNS
137
PNS visceral afferent
incoming information from internal viscera
138
PNS sensory afferent
- somatic: sensation from body surface and proprioception
- special senses: vision, hearing, smell, taste
139
PNS efferent division
send information from the CNS to muscles and glands
140
perception
conscious interpretation of external world derived from sensory input
141
does pure sensory input give true reality perception
no
142
why does pure sensory input not give true reality perception
- human receptors only detect a limited number of stimuli
- limited resolution (information channels are not high-fidelity records)
- information can be enhanced/suppressed when it reaches our brain
- brain interprets and distors information to extract conclusions
- interpretation affected by cultural, social, and personal experiences
143
stimulus
a change detectable by the body
144
different modalities of stimuli
heat, light, sound, etc.
145
stimulus receptors
structures at peripheral endings of afferent neurons
146
receptors function
convert stimuli into electrical signals
147
stimulus sequence
148
sensory system parts
sensory receptors, their axonal pathways, and perception target areas in the brain
149
modalities
different classes
150
specialized sensory receptors detect ....
different stimuli classes
151
exteroceptors
specialized neurons on the outside of the body
152
interoceptors
specialized neurons on the inside of the body
153
exteroceptors/interoceptors function
transduction
154
transduction
the process of converting energy from a stimulus into electrical signals via receptor/generator potential which triggers an action potential if thresholds are reached
155
photoreceptors sense and stimulus
- vision
- light
156
mechanoreceptors sense and stimulus
- touch, balance, proprioception, hearing
- mechanical energy (stretching muscle, hair cell movement)
157
thermoreceptors sense and stimulus
- temperature
- heat and cold
158
chemoreceptors sense and stimulus
- smell, taste
- specific chemicals (O2, etc.)
159
nociceptors sense and stimulus
- pain
- excessive pressure, temperature, specific chemicals
160
where do primary afferent axons enter
the spinal cord through the dorsal roots
161
where do primary afferent axon somas remain
spinal cord dorsal root ganglia
162
nerve fiber types
- Aα
- Aβ
- Aδ
- C
163
efferent motor nerve fibers
- Aγ
- B
164
which nerve fiber do skin receptors lack
Aα
165
are C fibers myelinated or unmyelinated
unmyelinated
166
nerve fiber axon diameter
bigger diameter = lower resistance
167
unmyelinated voltage regulated channels function
- account for ion leakage across the membrane
- conduct impulses slowly
168
where is there ion leakage in myelinated axons
Nodes of Ranvier
169
where is graded potential generated
in a receptor cell or free nerve ending
170
graded potential is proportional to ...
stimulus strength
171
action potential is ....
all or nothing
172
receptor cell
173
free nerve ending
174
stimulus intensity is encoded in ...
- actional potential frequency
- the number of activated receptors
175
single sensory unit stimulation weak versus strong simulus
176
multiple sensory unit stimulation weak versus strong stimulus
177
receptor potential
- occur in seperate receptor cells
- stimulus opens ion channels causing graded membrane potential
- receptor cell releases chemical messenger
- chemical messenger opens ion channels in afferent neuron action potential
- if threshold is reached, actional potential is generated
178
generator potential
- occur in specialized nerve endings
- stimulus opens ions channels causing local current flow
- local current flow opens ion channels in afferent neuron action potential
- if threshold reached, action potential is generated
179
receptive field
a region of space in which the presence of a stimulus alters the firing of that neuron
180
receptive field example
- hair in the cochlea
- skin
- retina
181
size and shape of receptive fields may change due to ...
- connectivity (convergence, divergence, inhibition)
- synaptic properties
182
receptor transduction necessary components
- receptor must have specificity for the stimulus energy
- receptive field stimulation
- stimulus energy converted into a graded potential
- generator potential in the associated sensory neuron must reach threshold
183
adaptation
a change in sensitivity in the receptor cell to a long-lasting stimulus
184
types of adaptation
- PHASIC
- TONIC
185
PHASIC
- primarily by rapidly-adapting receptors
- pressure, touch, hearing, smell
- adapt quickly, respond less if stimuli remains constant
- allows us to shut out background noise
186
TONIC
- little adaptation by slowly adapating receptors
- pain, proprioception, chemicals in the blood or CSF
- adapt slowly, continue to respond even when stimulus remains constant
187
why is continuous input in TONIC useful
body needs to make sontinuous response to the information or the stimulus needs to be constantly evaluated
188
types of adaptational receptors
- proprortional receptors
- differential receptors
189
proportional receptors
provide continuous information about stimulus
190
differential receptors
signals changes in stimulus intensity
191
adaptation mechanisms types
- mechanical
- chemical
192
mechanical adaptation mechanisms
physical mechanical mechanism induces a receptor neuron response decrease
193
where are specialized receptor endings for mechanial adaptation mechanisms
in Pacinian skin cells
194
chemical adaptational
membrane enzymes or intracellular signalling mechanisms induce response termination
195
where is chemical adaptation mechanism common
olfactory response
196
phasic receptors of mechanical adaptation
- specialized receptor ending of concentric connective tissue layers
- sustained pressure causes layers to slip which dissipates stimulus intensity
197
phasic receptors of chemical adaptation
adaptation mediated by Ca2+:
- Ca2+ binding calmodulin decreases CNGC activity
- Ca2+ regulates AC III activity decreases cAMP
198
somatosensory system
neural sense concerned with body sensations
199
soma
greek word for body
200
somatosensory system divisions
- cutaneous (skin)
- visceral (internal organs and deep tissue)
- proprioception (body and limb awareness)
201
are somatosensory receptors distributed or concentrated
distributed
202
different somatosensory receptors respond to ...
different stimuli modalities
203
touch begins at ....
the skin
204
layers of the skin
- epidermis (outer)
- dermis (inner)
205
glabrous definition
skin free from hair (palm of hands, soles of feet, face, and ears)
206
which receptor is most common in relation to touch
mechanoreceptors
207
somatosensory receptors
- meissner's corpuscle
- merkel disc receptors
- ruffini ending
- pacinian corpuscle
- bare nerve endings
208
somatosensory receptors - meissner's corpuscle
- respond to touch
- fine and discriminative touch in glabrous skin
209
somatosensory receptors - merkel disc receptors
fiber connected to an epithelial cell
210
somatosensory receptors - ruffini ending
slowly adapting touch receptor
211
somatosensory receptors = pacinian corpuscle
- rapidly adapting
- vibration sensor
212
somatosensory receptors - bare nerve endings
pain and hear stimulation
213
if a sensory neuron supplies a large area then ...
touch discrimination will not be as fine
214
where are receptive fields identified
neurons of the autitory, somatosensory, and visual systems
215
more ? is dedicated to integrate information coming from the fingertips
brain tissue
216
somatosensory ascendant pathways
- 3rd order afferent
- 2nd order afferent
- 1st order afferent (primary sensory neuron)
217
3rd order afferent
- in thalamus
- project to primary somatosensory cortex
218
2nd order afferent
- in spinal cord
- synpase with 3rd order in thalamus
219
1st order afferent (primary sensory neuron)
- soma in peripheral sensory ganglion
- peripheral axon branch innervates receptors
- central axon synapses with 2nd order afferent neuron
220
dorsal column-medial lemniscal pathway carries information about ...
- fine touch
- vibration (ex: hand moving over surface)
- stimuli moving on skin
221
dorsal column-medial lemniscal pathway
222
where does information from the dorsal column-medial lemniscal pathway decussate
the medulla
223
is the dorsal column-medial lemniscal pathway ipsilateral or contralateral
contralateral (left side of body to right cortex, and vice versa)
224
lateral inhibition function
highlight edges of stimulus (contrast enhancement)
225
lateral inhibition
a neuron's response to a stimulus is inhibited by the excitation of a neighboring neuron
226
between two neurons which response will be inhibited
the weaker one
227
where is lateral inhibition common
vision and hearing
228
why is lateral inhibition good
enhances perception
229
in lateral inhibition, primary neuron response is _________________ to the stimulus strength
proportional
230
where does most somatosensory information get processed
primary somatosensory cortex
231
where is the primary somatosensory cortex located
parietal lobe
232
primary somatosensory cortex recieves inputs from....
ventral pallidum thalamic area
233
how responsive are neurons in primary somatosensory cortex to somatosensory stimuli
very
234
lesions in primary somatosensory cortex ...
impair somatic sensation
235
what happens when primary somatosensory cortex is electrically stimulated
evokes somatosensory experiences
236
somatotopic representation
representation of body mapped on the cortical surface
237
homunculus
- distorted map
- hands, fingers, and face receive greatest representation
238
phantom limb syndrome
ascending pathways stimulate primary somatosensory cortex from adjacent representation but descendent pathways interpret incorrectly
239
why do somatosensory cortexes reorganize
- basis of experience
- somatosensory input
240
posterior parietal cortex function
different sensory modality traits converge for proper sensory representation
241
agnosia
inability to recognize an object even though simple sensory skills are normal
242
consequence of posterior parietal lesions
spatial neglect
243
spatial neglect
- ignore contralateral extrapersonal space
- deny body parts (incomplete dressing)
- incomplete copyings of drawing
- body centered (memory recall depends on view point)
244
is spatial neglect a simple sensory loss? explain
no, concerned with representing visual and somatosensory space and actions within it
245
pain
an unpleasant sensory or emotional experience associated with actual or potential tissue damage
246
nociception
processing information about damaging stimuli by the nervous system where perception occurs
247
nociceptors
free nerve endings found in every tissue in the body except the brain
248
when are nociceptors activated
- in the presence of intense thermal, mechanical, or chemical stimuli
- tissue irritation or injury (releases chemicals that stimulate nociceptors)
249
which fibers are connected to nociceptors
c fibers
250
spinothalamic pathway
251
steps of vision
- transmission and refraction of light by optics of the eye
- transduction of light energy into electrical signals by photoreceptors
- signal refinement by synaptic interactions within retinal neural connections
252
visual processing path
253
wavelength
the distance between two peaks of the electromagnetics wave
254
rainbow effect
when white light diffracts through a prism it splits into a rainbow
255
what does a mix of visual light wavelengths usually appear as
white light
256
properties of visual light
- reflection
- refraction
- absorption
257
visual light property - reflection
light bouncing off of a surface
258
visual light property - refraction
- light rays bending when traveling
- the eye acts as a camera bending the light to focus it in the retina
259
visual light property - absorption
- transfer of light energy to a particle
- photoreceptors in the retina contain pigments that absorb light reflected by objects
- black objects absorb all the visual light wavelengths, green absorb all except green, etc.
260
frontal eye anatomy - macula
261
frontal eye anatomy - fovea
262
frontal eye anatomy - temporal retina (lateral)
263
frontal eye anatomy - nasal retina (medial)
264
frontal eye anatomy - optic disk
265
frontal eye anatomy - blood vessels
266
lateral eye anatomy - suspensory ligament
267
lateral eye anatomy - ciliary body
268
lateral eye anatomy - conjunctiva
269
lateral eye anatomy - lens
270
lateral eye anatomy - pupil
271
lateral eye anatomy - aqueous humour
272
lateral eye anatomy - cornea
273
lateral eye anatomy - iris
274
lateral eye anatomy - vitreous humor
275
lateral eye anatomy - blood vessels
276
lateral eye anatomy - optic disc
277
lateral eye anatomy - optic nerve
278
lateral eye anatomy - fovea
279
lateral eye anatomy - sclera
280
lateral eye anatomy - retina
281
lateral eye anatomy - choroid
282
lateral eye anatomy - extrinsic eye muscle
283
cornea and lens optic function
diffract light (refraction) to focus it in the retina
284
the lens will accommodate to different ____________
distances
285
retina
a layer of photoreceptors cells and glial cells that captures incoming photons and transmits them along neuronal pathways as both electrical and chemical signals for the brain to perceive a visual picture
286
which nervous system is the retina a part of
CNS
287
most direct pathway from the retina to the brain
photoreceptors -> bipolar cells -> ganglion cells
288
which cells are the only ones that generate action potentials
ganglion cells
289
the only light-sensitive cells
photoreceptors
290
retina output
ganglion cell axons in the optic nerve that lead to higher CNS centers
291
laminar organization definition
the way certain tissues are arranged in layers
292
retina laminar organization
293
retina interneurons
horizontal and amacrine cells
294
horizontal cell function
modulate transmission from photoreceptors to bipolar cells
295
amacrine cell function
modulate transmission from bipolar cells to ganglion cells
296
photoreceptors
transform electromagnetic radiation into electrical signals
297
photoreceptor types
- rods
- cones
298
rods
- night vision
- one photopigment
- black/white vision
- many membrane disks
- low spatial resolution but very sensitive to light
299
cones
- daylight vision
- 3 photopigments
- color vision
- high spatial resolution but insensitive to light
- does not operate in dim light
300
fovea has ____ cones than rods
more
301
periphery has ____ cones than rods
less
302
central retina cell composition
individual photoreceptors feeding into individual ganglion cells
303
periphery cell composition
many photoreceptors converge into individual ganglion cells
304
periphery
- more rods and greater input
- higher sensitivity
- larger receptor fields
- lower resolution
305
why is there lower sensitivity in the fovea
- more cones and no convergence of input
- one photoreceptor into one ganglion cell
306
why is there higher resolution in the fovea
- no convergence of input
- one photoreceptor into one ganglion cell
- direct light input
307
which photopigment is in rods
rhodopsin
308
what do cone photopigments require to be activated
more energy
309
3 cone types
- red
- blue
- green
310
how many types of light is each cone sensitive to
one
311
result of all cones being equally active
white light
312
which photopigment is in cones
opsins
313
total number of cones in the eyes
6 million
314
total number of rods in the eyes
100 million
315
phototransduction
conversion of light energy into membrane potential changes
316
result of graded changes in membrane potentials
change in transmitter release rate
317
phototransduction in the dark
- membrane depolarization
- Ca2+ channels open
- high transmitter release rate
318
phototransduction in the light
- membrane hyperpolarization
- Ca2+ channels close
- decreased transmitter release rate
319
photoreceptor depolarization cause
dark ("current of Na+")
320
photoreceptor depolarization process
- guanylyl cyclase produces cGMP in the dark
- cGMP binds and activates Na+ channels
- Na+ influx depolarizes the membrane
- membrane depolarization induces Glutamate liberation
321
photoreceptors hyperpolarization cause
light
322
photoreceptors hyperpolarization process
- absorption of light induces retinal cis isomer to become a trans isomer
- conformational change and transduction
- light activates rhodopsin and transducin
- transducin binding GTP activates PDE
- active PDE breaks down cGMP
- low levels of cGMP promote channel closing
- Na+ influx decreases, membrane hyperpolarizes
- hyperpolarization reduces glutamate release
323
what provides the isomers in photoreceptor polarization with conformational changes (trans to cis or cis to trans)
pigmented epithelium
324
rhodopsin components
opsin + retinal
325
transducin
a G protein
326
what polarizes bipolar cells
glutamate
327
bipolar cell types
- on center
- off center
328
on center bipolar cells are ________________________ by glutamate
hyperpolarized
329
off center bipolar cells are ________________________ by glutamate
depolarized
330
on center bipolar cells are ________________________ by light
depolarized
331
off center bipolar cells are ________________________ by light
hyperpolarized
332
on center bipolar cells
0 bound to glutamate during dark
- mGluR6 closes Na+ channels
- hyperpolarization reduces glutamate release, reduces mGluR6 binding, and allows Na+ channels to open
333
off center bipolar cells
AMPA/Kainate R expression
334
bipolar cell receptive field
area of retina where a stimulus will evoke a response
335
bipolar cell receptive field center
direct connect from photoreceptors
336
bipolar cell receptive field surround
connection from photoreceptors through horizontal cells
337
bipolar cell receptive field rule
whatever response is triggered in the center, the opposite will be triggered by the surround
338
ganglion cell receptive field
the area of a retina where a stimulus will evoke a response in that ganglion cell
339
ganglion cell receptive field rule
light in the center will have the opposite effect than light in the surround
340
ganglion cell types
- on center
- off center
341
on center ganglion cells
produce action potentials when light is shone on the receptive field center
342
off center ganglion cells
decrease action potentials when light is shone on the receptive field center
343
photoreceptors are always hyperpolarized by _______ but .... ?
- light
- action potential firing in the ganglion cell may increase or decrease
344
is the change in firing rate extremely high or low if receptive field center and surround are in the same illumination
there is no change (A,C, and E)
345
is the change in firing rate extremely high or low if receptive field center and surround are in the contrast
greatest difference (B and E)
346
antagonistic center/surround effect mediated by horizontal cells
- reduced hyperpolarization of center cone
- increased release of glutamate from center cone
- hyperpolarization of bipolar cell
- hyperpolarization and reduced firing of ganglion cell
347
what do horizontal cells regulate
the amount of transmitter released by photoreceptor onto bipolar cell
348
horizontal cell hyperpolarization
surround cone releases less glutamate onto horizontal cell
349
ganglion cell response reflect ...
differences in contrast
350
vision neural level process
- light energy converted to membrane potential changes. in photoreceptor cells through opsin -> transducin -> PDE -> CNG Channel -> Glutamate
- glutamate information converted into membrane potential changes in bipolar (center on/off) and horizontal (surround on/off) cells
- processed information converted into action potentials. in ganglion cells
- transmitted to the brain via the optic nerve
351
systems of the ear
- auditory
- vestibular
352
vestibular system
- balance
- inform the brain of head and body position and how they are moving
353
auditory system
- hearing
- detect sounds, localize, and identify sound nuances
354
types of air that compose sound
- compressed air
- rarefied air
355
frequency unit and equation
cycles/second (Hz)
356
sound features
- pitch
- intensity
- timbre
357
pitch
- tone
- dependent on frequency
358
intensity
- loudness
- depends on amplitude
359
timbre
- quality
- depends on overtones
360
sound amplitude
decibels (dB)
361
auditory threshold
0 dB
362
speech freqeuncies
500-4000 Hz
363
auditory thershold varies with ...
frequency
364
what do low and high frequencies require to be audible
higher sound levels
365
what sounds can humans not hear and give examples
- infra sound (whales, muscles moving)
- ultra sound (bats)
366
auditory system process
367
3 main parts of the ear
- outer ear
- middle ear
- inner ear
368
outer ear features
- pinna (auricle)
- auditory canal
369
ear - pinna
370
ear - auditory canal
371
middle ear features
- ossicles: malleus, incus, stapes
- tympanic membrane
372
ear - ossicles
373
ear - tympanic membrane
374
inner ear features
- labyrinth/semicircular canals
- oval window
- round window
- auditory-vestibular nerve
- cochlea
375
ear - labyrinth/semicircular canals
376
ear - oval window
377
ear - round window
378
ear - auditory-vestibular nerve
379
ear - cochlea
380
auditory system pathway
- cochlea
- brainstem
- thalamus
- primary auditory cortex
381
middle ear amplification features
- malleus
- incus
- stapes
- oval window
- cochlea
- eustachian tube
- tympanic membrane
- auditory canal
382
oval window pressure tympanic membrane pressure
>
383
pressure equation
force/surface
384
middle ear - malleus
385
middle ear - incus
386
middle ear - stapes
387
middle ear - eustachian tube
388
what connects the malleus to the skull
tensor tympani muscle
389
what connects the stapes to the skull
stapedius muscle
390
attenuation reflex
- after a loud sound, tensor tympani muscle and stapedius muscle tense, impairing amplification system
- protective reflex
- adaptation to loud sounds
- not hearing our own speech
391
ear - tensor tympani muscle
392
ear - stapedius muscle
393
cochlea features
- bony cochlear wall
- scala vestibuli
- scala media
- tectorial membrane
- basilar membrane
- scala tympani
- spiral ganglion
- vestibular membrane
- organ of corti
- cochlear branch of vestibulocochlear nerve
394
(transverse section) cochlea - bony cochlear wall
395
(transverse section) cochlea - scala vestibuli
396
(transverse section) cochlea - scala media
397
(transverse section) cochlea - tectorial membrane
398
(transverse section) cochlea - basilar membrane
399
(transverse section) cochlea - scala tympani
400
(transverse section) cochlea - spiral ganglion
401
(transverse section) cochlea - cochlear branch of vestibulocochlear nerve
402
(transverse section) cochlea - organ of corti
403
(transverse section) cochlea - vestibular membrane
404
(coronal section) cochlea - oval window
405
(coronal section) cochlea - round window
406
(coronal section) cochlea - tectorial membrane
407
(coronal section) cochlea - basilar membrane
408
(coronal section) cochlea - organ of corti
409
(coronal section) cochlea - cilia
410
(coronal section) cochlea - auditory nerves
411
(coronal section) cochlea - perilymph
412
(coronal section) cochlea - endolymph
413
where do the scala vestibuli and scala tympani communicate
the apex of the cocohlea
414
where does the perilymph flow
from vestibuli to tympani when stapes taps the oval window
415
where does the endolymph flow
inside the scala media
416
where is the basilar membrane widest and most flexible
the apex
417
are individual frequencies detected by the same parts of the cochlea
no
418
where in the cochlea are high frequencies detected
near oval window (stiff)
419
where in the cochlea are low frequencies detected
near apex wide (flexible)
420
organ of corti parts
- outer hair cell
- stereocilia
- tectorial membrane
- reticular lamina
- modiolus
- spiral ganglion
- auditory nerve
- inner hair cell
- rods of corti
- basilar membrane
421
organ of corti - outer hair cell
422
organ of corti - stereocilia
423
organ of corti - tectorial membrane
424
organ of corti - reticular lamina
425
organ of corti - modiolus
426
organ of corti - spiral ganglion
427
organ of corti - auditory nerve
428
organ of corti - inner hair cell
429
organ of corti - rods of corti
430
organ of corti - basilar membrane
431
inner ear transduction process
- upward displacement of basilar membrane creates force that laterally
displaces stereocilia
- mechanical displacement of the stereocilia in a lateral direction cause hair cell depolarization
- downward displacement of the basilar membrane creates force that results in
lateral displacement of the stereocilia in the opposite direction (hyperpolarization of the
hair cell)
