Final Extra Content Flashcards
(177 cards)
1
Q
Name dominant NT released by most SNS postganglionic neurons
A
norepinephrine / noradrenaline
2
Q
- Name of ligand-binding cholinergic channel and its physiologic agonist
A
nicotinic - acetylcholine
3
Q
- Name of dominant neurotransmitter released as a hormone by the
adrenal gland
A
epinephrine / adrenaline
4
Q
- Receptor name for metabotropic receptor that binds epinephrine
A
adrenergic
5
Q
- The terminal cisternae are part of which organelle in the muscle cell?
A
sarcoplasmic reticulum
6
Q
The gamma neuron excites intrafusal fibers
to stretch and trigger the stretch reflex
A
false
Gamma motor neurons do not directly cause the stretch reflex by exciting intrafusal fibers. Instead, they play an indirect role by maintaining the muscle spindle’s sensitivity to changes in length, ensuring it remains functional across different muscle lengths.
7
Q
explain IA muscle spindle process
A
stretch –> spindle sensor –> Ia afferent –> alpha motor neuron –> extrafusal muscle fiber –> muscle shortening
8
Q
draw 8.1 slide 15
A
9
Q
Most postganglionic sympathetic
neurons are adrenergic…
But, there are a few cholinergic
A
sweat glands and pilooreceptor muscles in skin
10
Q
Consider an external stimulus that causes
heart rate to increase (i.e.: sudden loud noise).
Which branch of the ANS can change its
neuron firing rates in a way that can produce
an increase in heart rate?
A
sympathetic
11
Q
Which of the following are “Motor” neurons?
A. cholinergic Aα
B. cholinergic B
C. cholinergic C
D. adrenergic C
E. all of the above
A
all of the above
12
Q
T/F: “Some sympathetic postganglionic
neurons release Acetylcholine.”
A
true
13
Q
Where do sympathetic postganglionic neurons release acetylcholine?
A. cardiac tissue
B. blood vessels
C. some sweat glands
D. cortical region of brain
E. none of the above
A
some sweat glands
14
Q
What receptor would you expect to find on
sweat glands innervated by the
sympathetic nervous system?
A. nicotinic
B. muscarinic
C. adrenergic
D. all of the above
A
muscarinic
15
Q
What receptor would you expect to find on
cardiac cells innervated by the
sympathetic nervous system?
A. nicotinic
B. muscarinic
C. adrenergic
D. all of the above
A
adrenergic
16
Q
Which of the following is true of the parasympathetic nervous system?
A. very short preganglionic neurons
B. synapse in ganglia close to spinal cord
C. all cholinergic neurons
D. none of the above
E. only B and C
A
all cholinergic neurons
17
Q
Consider an external stimulus that causes
heart rate to increase (i.e.: sudden loud noise).
Which branch of the ANS can change its
neuron firing rates in a way that can produce
an increase in heart rate?
a. Sympathetic
b. Parasympathetic
c. Both Sympathetic and Parasympathetic
A
Both Sympathetic and Parasympathetic
18
Q
Beta Blockers are a class of drugs that act on Beta
adrenergic receptors on the heart. A common Beta
Blocker is metoprolol (lopressor) that specifically
blocks Beta 1 adrenergic receptors. The Beta 1
receptor is a G-protein coupled receptor with a Gs
alpha subunit. If metoprolol is given, which branch of the autonomic
nervous system is most likely to be affected?
a. sympathetic
b. parasympathetic
c. both sympathetic and parasympathetic
A
sympathetic
19
Q
cerebral cortex
A
higher reasoning; abstract thought, memory, visual / auditory processing movement / sensory processing
20
Q
diencephalon
A
thalamus – receive and distribute input
hypothalamus – regulate homeostatic functions
21
Q
Brain Stem
A
(midbrain, pons, medulla)
sensory motor relays regulation of vital functions
22
Q
cerebellum
A
posture / balance
timing / coordination of movement
23
Q
basal nuclei
A
organizing motor behavior
suppressing unnecessary movements
24
Q
limbic system
A
amygdala – emotions
hippocampus – new memory formation
25
Patient recognizes their mother’s face but
believe it to be an imposter
Imposter Syndrome
Fusiform gyrus is intact, but
connection to amygdala is severed.
Recognize face, but no emotional
response (when there should be)
26
Phantom limb pain and
mirror box
Brain perceives the arm is moving again, so the
“learned paralysis” is unlearned.
Often the phantom arm disappears after
practicing with mirror box.
27
Synaesthesia
Sensory input stimulates
multiple senses.
Numbers or words have colors
Musical notes have colors
28
What is the
neurological basis
of synaesthesia?
Color and number areas are right next to each
other in the fusiform gyrus.
Less trimming of the neurological connections in
the brain which connect the perception of
various senses.
29
mirror touch synesthesia
Individuals experience touch and emotions when
observing others being touched.
MTS is associated with a specific deficit in
inhibiting representation of other individuals.
Runs in families
30
What area of the brain is primarily associated
with long-term memory formation?
hippocampus
31
What structure allows for communication
between the two hemispheres of the brain?
corpus callosum
32
What area of the brain allows for interpretation
of words via visual input (reading)?
angular gyrus (wernicke's area)
33
Which structure relays motor and most sensory
information to cerebral cortex?
thalamus
34
A patient is able to properly identify
objects when viewing them or when
feeling them with her right hand.
However the patient is unable to
identify the same objects when felt
with the left hand. Sensory tests
indicate that the touch ascending
pathway to the brain is intact.
What brain area is likely affected and
why?
Right somatosensory association area.
35
In the TV show “Grey’s Anatomy” a patient has
come to the hospital because of a suspected
stroke. The patient does not seem to understand
anything the interns are saying and responds
with random words. The patient recoils in fear
when one of the interns gets frustrated and
starts yelling and waving his arms at her. She
seems to be calmed by music, and kind gestures,
but cannot respond coherently to anything that is
said to her, or anything that she is given to read.
What is the best explanation for a neurological deficit
that could produce these symptoms?
Damage to the Wernicke’s area.
36
An ER patient is not able to verbally identify objects
(i.e. see a photo of a phone and say the word "phone"),
however, when he is told to choose the object from a
set of photos, he is able to point it out. Which area of
the brain is likely affected in this case?
a. Dominant Wernicke's area
b. Fusiform Gyrus
c. Broca's area
d. Both A and B
e. Both B and C
fusiform gyrus
37
visual cortex
processing visual input regarding apple processed in
38
frontal lobe
desire for apple
39
supplementary motor area
a part of the frontal cortex of the brain that's involved in several motor and non-motor functions
40
premotor area
creates motor image of orientation and relation to target prior
to stimulating primary motor cortex
41
primary motor cortex
cell bodies associated with the activation of muscles in each
area of the body
42
pyramidal tract/corticospinal tract
descending neurons from
cortex to interneurons/motor neurons of spinal cord
neurons that connect cortex to the spinal cord’s
interneurons/motor neurons
43
motor neurons
stimulate muscles of shoulder arm & hand to pick
up apple
44
cerebellum
compares sensory information regarding movement (in
real time) with motor image and make corrections as needed
45
Supplementary motor area
preparatory role in programming complex sequences of
movement
46
Posterior parietal cortex
provides sensory input to guide premotor area
47
Name the part of the brain that compares the
desired motor program (motor output) with
incoming sensory information to ensure we
produce smooth coordinated movements.
a. cerebellum
b. premotor cortex
c. motor cortex
cerebellum
48
How can cerebellum be so important for
movement when it has no direct ability to
cause muscle contraction?
* Helps sequence motor activities
* Monitors and makes corrective adjustments
49
Visual Processing steps
1. Light enters eye
passes through cornea and pupil
focused by lens onto the retina
2. Photoreceptors transduce light energy
changes electromagnetic energy into electrical signals
3. Electrical signals transmitted to brain
eventually allows visual perception
50
photoreceptors
Light travels through retinal cells
stimulates the photoreceptors
and is absorbed in posterior layer of eyeball
51
Which photo receptor has higher convergence to ganglion cells?
rods
52
What part of the eye is loaded with millions of photoreceptors?
retina
53
What are the two layers of this part of the eye (and what do they do)?
neural layer and pigmented
54
Which of these neurons produce action potentials?
photoreceptors, bipolar cells, ganglion
55
Where are most of the cones located in the retina?
near the center
56
Where are most of the rods located in the retina?
around the edges
57
Which photoreceptors demonstrate high convergence?
(i.e. many neurons merging onto one neuron)
rods
58
rods
– dim light, night vision
– black & white,
– less acuity due to higher
degree of convergence
– dominate periphery of retina.
59
cones
– color vision
– better acuity due to less
convergence
– cones dominate in middle of
retina (especially fovea).
60
fovea
small depression where ganglion
and bipolar cells are pulled to side
entral pit composed of closely packed cones
61
Macula lutea
small area around fovea
fairly high acuity
62
What is the function of melanin expressed in the pigmented epithelium?
Melanin in the pigmented epithelium functions to absorb light.
63
What happens if there is no melanin in the pigmented epithelium?
Individuals without pigmentation have reduced visual acuity and are sensitive to light (photosensitivity).
64
What enzyme stopped cAMP signaling?
A. adenylyl cyclase
B. phosphodiesterase
C. protein kinase A
D. protein kinase C
E. phospholipase C
phosphodiesterase
65
How is the photoreceptor cell more
depolarized at rest than other cells
we’ve seen?
cGMP keeps Na+ channels in outer
segment open!
66
draw 10.1 slide 21
67
Name the cells of the retina neural
layer.
photoreceptor cells (rods and cones), bipolar cells, ganglion cells, horizontal cells, and amacrine cells
68
ganglion cells
the final neurons in the retina that transmit visual information to the brain
69
horizontal cells
responsible for increasing contrast via lateral inhibition and adapting both to bright and dim light conditions
- inhibitory
70
amacrine cells
neurons in the retina that integrate and modulate signals between bipolar and ganglion cells
71
Which of the following are true about the synaptic connections in the retina?
a. Rods and cones synapse directly to ganglion
cells.
b. Ganglion cells are the only retinal cells with
an action potential.
c. Bipolar cells synapse with ganglion cells and
photoreceptors.
d. All of the above.
e. Only B and C
Ganglion cells are the only retinal cells with
an action potential.
72
What happens to rhodopsin when
it absorbs light?
a. trans retinal changes to cis retinal
b. cis retinal changes to trans retinal
c. cis opsin changes to trans opsin
d. trans opsin changes to cis opsin
cis retinal changes to trans retinal
73
What results from forming
“activated” rhodopsin?
a. Activates phosphodiesterase enzyme.
b. Results in increased intracellular cGMP.
c. Results in decreased intracellular cGMP.
d. Only A and C.
e. Only B and C.
Activates phosphodiesterase enzyme
74
How does cGMP affect cation
channels and ion flow?
a. When cGMP is bound to membrane ion
channels, the channels are closed.
b. When cGMP is bound to membrane ion
channels, the channels are open.
c. cGMP is not involved with ion channel
opening
When cGMP is bound to membrane ion channels, the channels are open
75
When light activates a rod or
cone cells, does it depolarize or
hyperpolarize?
a. depolarize
b. hyperpolarize
hyperpolarize
76
label 10.1 slide 27 / 28
77
what can cis-retinal can bind to
opsin proteins
78
what happens when photochemicals are exposed to light
they change shape
79
how does light effect cis-retinal
light triggers cis-retinal to convert to trans-retinal
“straighter” structure can no longer bind to protein
80
what does activated rhodopsin (no retinal bound) activate
G-protein transducin
81
what does transducin activate
phosphodiesterase
82
what does cGMP activate
cGMP normally activates Na+ channels in photoreceptors, so
decreasing cGMP levels reduces Na+ influx
83
how do closed sodium channels depolarize / hyperpolarize
closed Na+ channels causes rod to hyperpolarize
84
How does hyperpolarization
affect neurotransmitter release?
There is tonic release of glutamate in the
absence of light due to open sodium & calcium channels depolarizing the cell.
Hyperpolarization decreases
glutamate release.
85
Color vision results from activation of cones.
blue, green, red
pigment portion same as in rods (retinal)
protein portion different for each color of cone
86
how do cones receive light
Each cone is receptive to a particular
wavelength of light
S-type (short) photopigment
M-type (medium) photopigment
L-type (long) photopigmen
87
s-type photopigment
short
blue cone
88
m-type photopigment
medium
green cone
89
l-type photopigment
long
red cone
90
how do colors show up
The perception of colors depends
on ratio of cone activation
91
Which of the following is true of
horizontal cells?
a. Their electrical signals are always inhibitory
b. Their electrical signals are always excitatory
c. They enhance visual contrast
d. Both A and C
e. Both B and C
Both A and C
92
Which of the following are true regarding the
path of the neuronal activity to the brain?
a. Bipolar cell axons make up the optic nerve.
b. All visual stimuli from the right eye travels to
the left hemisphere of the brain.
c. The optic nerve fibers terminate in the lateral
geniculate nucleus of the thalamus.
d. All of the above.
d. All of the above.
93
Which of the following makes a direct
connection with the round window?
a. the incus
b. the stapes
c. the malleus
d. none of the above
d. none of the above
94
What is the function of the
round window?
acts as a pressure release valve in the inner ear, allowing fluid within the cochlea to move in response to vibrations entering through the oval window
95
When contracted, the stapedius
muscle and tympani muscle
a. Amplify sound conduction
b. Attenuate sound conduction
c. Reduce high-frequency conduction
d. Filter 1000- to 2000-Hz noise
b. Attenuate sound conduction
96
Impedance
the opposition to the transfer of acoustic energy from one medium to another
* Total opposition to motion
* Opposition of a system to the flow of energy
into it and through it
* Inner Ear is fluid therefore, the Middle Ear
must overcome or “match” the impedance
97
What are the two main mechanisms of middle-ear gain?
The two main mechanisms are Acoustic Coupling and Ossicular Coupling.
98
What is Acoustic Coupling in the middle ear?
sound naturally enters the middle ear (whether or not it triggers the ossicles) and is picked up by the round window
99
What is Ossicular Coupling in the middle ear?
Ossicular coupling refers to the mechanical connection between the ossicles (malleus, incus, and stapes) that helps transmit sound vibrations.
100
How does the Area Difference contribute to middle-ear gain?
The area difference between the tympanic membrane and the footplate of the stapes increases pressure at the footplate, amplifying sound energy.
101
How does the Lever Action of the ossicles contribute to middle-ear gain?
The lever action between the malleus and incus increases the force applied to the stapes, further amplifying sound transmission.
102
annotate 10.1 slide 52
103
does the scala vestibuli / scala tympani have endolymph or perylymph
perylymph
104
does the cochlear duct have endolymph or perylymph
endolymph
105
perilymph contents
high levels of sodium ions and low levels of potassium ions
106
endolymph contents
high levels of potassium ions and low levels of sodium ions
107
What are the main types of cells in the organ of corti?
The main types of cells in the organ of corti are supporting cells, one row of inner hair cells, and three rows of outer hair cells.
108
What is the role of supporting cells in the organ of corti?
Supporting cells help maintain the structure and function of the spiral organ, but they do not play a direct role in sound transduction like hair cells.
109
How many rows of inner hair cells are found in the spiral organ?
There is one row of inner hair cells in the spiral organ.
110
How many rows of outer hair cells are found in the spiral organ?
There are three rows of outer hair cells in the spiral organ.
111
What is the basilar membrane?
The basilar membrane is a structure in the cochlea that vibrates in response to sound waves, playing a critical role in the process of hearing.
112
Where is the basilar membrane located?
The basilar membrane is located within the cochlea, situated between the scala tympani and scala media.
113
What role does the basilar membrane play in hearing?
The basilar membrane vibrates in response to sound frequencies. Its movement stimulates the hair cells in the cochlea, leading to the conversion of sound vibrations into electrical signals sent to the brain.
114
How does the basilar membrane respond to different frequencies?
The basilar membrane has a tonotopic organization: higher frequencies cause vibrations near the base (narrow, stiff region), while lower frequencies cause vibrations near the apex (wider, more flexible region).
115
What happens if the basilar membrane is damaged?
Damage to the basilar membrane can impair the ability to process sound frequencies, leading to hearing loss or reduced sound discrimination.
116
How many rows of hair cells are in the cochlea?
There is one row of inner hair cells and three rows of outer hair cells in the cochlea.
117
What is the primary function of inner hair cells?
Inner hair cells are responsible for transducing sound vibrations into electrical signals that are sent to the brain via the auditory nerve.
118
What is the primary function of outer hair cells?
Outer hair cells amplify sound vibrations and help fine-tune the sensitivity of the cochlea, improving auditory perception, especially for quiet sounds.
119
How are inner hair cells connected to the auditory nerve?
Inner hair cells are directly connected to the auditory nerve fibers, transmitting electrical signals to the brain for sound processing.
120
How do outer hair cells affect the basilar membrane?
Outer hair cells contract and expand (a process called somatic motility), which enhances the movement of the basilar membrane, boosting sound detection sensitivity.
121
What happens if outer hair cells are damaged?
Damage to outer hair cells leads to a loss of cochlear amplification, reducing hearing sensitivity, especially for soft sounds, but it doesn't usually cause total hearing loss.
122
What happens if inner hair cells are damaged?
Damage to inner hair cells results in permanent hearing loss, as they are responsible for sending the auditory signals to the brain.
123
Does hair cell itself generate action potentials?
no
124
What causes the excitation of hair cells in the cochlea?
The excitation of hair cells is caused by the deflection of stereocilia on the hair cells in response to sound vibrations.
125
What happens when the stereocilia are deflected?
Deflection of stereocilia opens mechanically gated ion channels, allowing ions to flow into the hair cell.
126
What type of ion causes the graded potential in hair cells?
An inward potassium current (from the endolymph) causes a graded potential in the hair cell.
127
What happens after the graded potential in hair cells?
The graded potential leads to the release of the neurotransmitter glutamate, which transmits the signal to the auditory nerve.
128
How are auditory signals sent to the brain?
Cochlear nerve fibers transmit the electrical impulses generated by the hair cells to the brain for auditory processing.
129
What happens to ion channels in the resting state in hair cells?
In the resting state, some ion channels in the hair cells are open due to the position of the stereocilia relative to the kinocilium, allowing for a small flow of ions and a baseline release of neurotransmitter.
130
What occurs during depolarization of hair cells?
During depolarization, the stereocilia are deflected toward the kinocilium (tallest appendage), causing more ion channels to open. This increases ion influx and enhances the release of neurotransmitters, sending a stronger signal to the auditory nerve.
131
What happens during hyperpolarization of hair cells?
During hyperpolarization, the stereocilia are deflected away from the kinocilium, causing ion channels to close, reducing ion flow and decreasing neurotransmitter release, resulting in a weaker signal.
132
Low-frequency sound causes which portion
of the basilar membrane to vibrate?
a. the portion close to the oval window
(the base)
b. the middle portion of the basilar
membrane
c. all along the length of the basilar
membrane
d. the portion close to the apex
the portion close to the apex
133
pitch
Perception of different frequencies
▪ Normal range is from 20-20,000 Hz --> cycle / second --> greater waves = higher pitch
▪ The higher the frequency, the higher the pitch. --> vibrates near the base
134
Tonotopic arrangement of basilar membrane
Different sound frequencies resonate the
basilar membrane at different locations.
135
What determines pitch detection in the auditory system?
Pitch detection is determined by three main factors:
- Tonotopic arrangement of the basilar membrane
- Frequency selectivity of inner hair cells
- Tonotopic arrangement of the auditory cortex
Flashcard 2
136
How does the tonotopic arrangement of the basilar membrane contribute to pitch detection?
The tonotopic arrangement means different frequencies cause the basilar membrane to vibrate at different locations: high frequencies affect the base, while low frequencies affect the apex.
137
How do inner hair cells contribute to pitch detection?
The frequency selectivity of inner hair cells allows them to respond preferentially to specific frequencies, helping detect pitch based on which cells are activated.
138
What role does the tonotopic arrangement of the auditory cortex play in pitch detection?
The auditory cortex has a tonotopic organization, where neurons are arranged according to the frequency of sound they process, allowing for the interpretation of different pitches in the brain.
139
loudness
- Perception of sound intensity
- Normal range is 0–120 decibels (dB) --> spatial summation
140
What is the main role of inner hair cells in the auditory system?
Inner hair cells are the main source of afferent signals in the auditory (VIII) nerve, with about 10 afferents per hair cell. They transmit auditory information to the brain.
141
How do inner hair cells contribute to the perception of loudness?
the more Inner hair cells activated around (spatial summation) the louder the sound
142
What is the role of outer hair cells in the auditory system?
Outer hair cells primarily have efferent inputs that control the stiffness of the basilar membrane, helping to amplify or dampen membrane vibration, which affects sound processing.
143
How do outer hair cells respond to sound intensity?
Outer hair cells respond to both low and high intensity sounds, but their main function is to adjust membrane stiffness, helping to enhance or suppress sound vibrations for better auditory perception.
144
What do outer hair cells contain that allows them to change shape?
Outer hair cells contain actin, a contractile protein that enables them to change shape.
145
How does actin in outer hair cells contribute to hearing?
The contractile properties of actin in outer hair cells allow them to contract and elongate, which adjusts the stiffness of the basilar membrane and amplifies or dampens sound vibrations.
146
Why is the contractile behavior of outer hair cells important for hearing?
The contractile behavior of outer hair cells helps fine-tune the sensitivity of the cochlea, enhancing the detection of quiet sounds and improving the clarity of auditory signals.
147
Which of the following statements is correct?
a. The amplitude of sound is determined by the position of
displacement along the basement membrane of the
cochlea.
b. The outer hair cells of the organ of Corti transduce the
sound signal.
c. Amplitude of sound is determined by the amount of
displacement of the basement membrane of the
cochlea.
d. Frequency of sound is determined by the amount of
displacement along the basement membrane of the
cochlea.
c. Amplitude of sound is determined by the amount of displacement of the basement membrane of the cochlea.
148
What is the Organ of Corti?
The Organ of Corti is the sensory organ located within the cochlea that contains the hair cells (inner and outer), which are responsible for transducing sound vibrations into neural signals.
149
What is the role of the Organ of Corti in hearing?
The Organ of Corti converts mechanical sound vibrations into electrical signals through the movement of hair cells, which then send the signal to the brain via the auditory nerve.
150
What is the Cochlea?
The Cochlea is a spiral-shaped, fluid-filled structure in the inner ear responsible for converting sound waves into electrical signals that are interpreted by the brain.
151
What is the relationship between the Organ of Corti and the Cochlea?
The Organ of Corti is located within the cochlea, and it is the part of the cochlea that contains the hair cells necessary for sound transduction.
152
Where is the Organ of Corti located within the cochlea?
The Organ of Corti is located on the basilar membrane inside the cochlear duct, which runs along the length of the cochlea.
153
154
How does the Cochlea contribute to hearing?
The Cochlea plays a critical role in hearing by transforming sound vibrations into neural signals through the Organ of Corti, where the hair cells detect and convert mechanical vibrations into electrical signals
155
What is the difference between a Cochlear Implant and a Hearing Aid?
- A Cochlear Implant is a surgical device that directly stimulates the auditory nerve, bypassing damaged parts of the inner ear, and is used for individuals with severe to profound sensorineural hearing loss.
- A Hearing Aid is a non-invasive device that amplifies sound for individuals with mild to moderate hearing loss, working by amplifying sound to make it more detectable for the ear.
156
What is the Oval Window?
The oval window is a membrane-covered opening between the middle ear and the inner ear, through which sound vibrations are transmitted from the stapes to the cochlea.
157
What is the function of the Round Window?
The round window is a membrane-covered opening in the cochlear wall that allows for the dissipation of sound vibrations, enabling proper fluid movement within the cochlea.
158
What is the role of the Cochlea in hearing?
The cochlea is the spiral-shaped structure in the inner ear that converts sound vibrations into electrical signals, which are then transmitted to the brain via the auditory nerve.
159
What is the Vestibular Apparatus?
The vestibular apparatus is the part of the inner ear responsible for balance and equilibrium, consisting of the semicircular canals, utricle, and saccule.
160
What does Equilibrium refer to in the vestibular system?
Equilibrium refers to the body's ability to maintain balance and orientation in space, which is detected by the vestibular apparatus and communicated through the vestibular nerve fibers.
161
What is the function of Hair Cells in the cochlea and vestibular system?
Hair cells are sensory cells that detect mechanical vibrations or movement. In the cochlea, they convert sound vibrations into electrical signals. In the vestibular system, they detect changes in head position and motion for balance.
162
What is the role of Vestibular Nerve Fibers?
Vestibular nerve fibers transmit signals from the vestibular apparatus to the brain, helping the body maintain balance and sense of motion and orientation.
163
What is the function of the Semicircular Canals?
The semicircular canals are part of the vestibular apparatus and detect rotational movements of the head, playing a key role in maintaining balance and equilibrium.
164
for both taste and smell, what
happens prior to the chemicals
stimulating the receptors?
Dissolved in aqueous solution: mucus or saliva
165
When looking at a tongue, the
bumps you see on the surface
are the “taste buds”.
a. True
b. False
false
166
where are the tastebuds
the side of the tongue
10.2 slide 41
167
are taste buds are epithelial or nerve cells
epithelial cells
168
Which of the following are true regarding
transduction of chemical signals into APs?
a. The taste receptor cells depolarize with open
ion channels and/or 2nd messenger actions.
b. The taste receptor cell sends an action
potential down its axon.
c. The taste receptor cell communicates with the
sensory nerve fibers, which transmits the
signal via an action potential.
d. Only A and B.
e. Only A and C.
e. Only A and C.
169
which senses are gpcrs
sweet, bitter, and umami
170
which senses are ion channels
salty and sour
171
taste g-protein pathway
– G protein (example: gustducin)
– Gβγ subunit activates isoform of Phospholipase C
– PLC increases production of IP3 and DAG
– IP3 opens Ca2+ ion channels on endoplasmic reticulum and Ca2+ is released into cytoplasm
– Leads to Na+ influx, cell depolarization, and ATP secretion.
172
What causes depolarization in sour taste cells?
Protons (H⁺) inhibit K⁺ efflux, which leads to depolarization of the taste receptor cells.
173
How is salty taste transduced in taste cells?
Na⁺ influx through ion channels leads to depolarization of the taste receptor cells, signaling a salty taste.
174
How does an odorant molecule trigger a response in olfactory receptor neurons?
When an odorant molecule binds to the GPCR on the cilia of olfactory receptor neurons (ORNs), it activates a second messenger pathway.
175
What is the role of the second messenger system in olfactory transduction?
The second messenger system, usually involving cAMP or IP3, opens cation channels (like Na⁺ and Ca²⁺), leading to depolarization of the olfactory receptor neuron.
176
How is the signal transmitted from the olfactory receptor neuron to the brain?
After depolarization, an action potential is generated and transmitted along the olfactory nerve fibers to the olfactory bulb in the brain.
177
describe odorant g-protein pathway
- odorant converted into neuronal signals?
– G-protein coupled receptor in cilia
– Activates adenylate cyclase
– Increases cAMP
– Opens cAMP gated sodium/calcium channels
(Na+ & Ca2+ influx) and then subsequently
calcium gated Cl- channels (Cl- efflux).
– Voltage-gated channels open at axon hillock –
action potentials along axon - neurotransmitter
