1
Q
The oldest sense are:
A
Chemical
2
Q
Chemical senses important for:
A
- hunger
- emotion
- sex
- memory
3
Q
Word for chemical taste:
A
gustation
4
Q
Word for chemical smell:
A
Olfaction
5
Q
What are chemoreceptors?
A
monitor environment; detects chemicals
6
Q
Other names for chemicals
A
- tastants
- odorants
7
Q
Papillae are:
A
bumps are your tongue
8
Q
Papillae ridges called:
A
foliate
9
Q
Each taste bud has ____ taste receptors
A
50-150
10
Q
T/F:
Taste cells are neurons
A
FALSE. They are chemical receptors
11
Q
Chemicals can cause a _________ receptor potential in taste cells
A
depolarizing
12
Q
Taste cell receptor potentials activate ____-_____ ___ channels and release NT
A
volt.dep Ca2+
13
Q
While taste cells are not neurons, they can ____-
A
release NT
14
Q
What flavors release serotonin?
A
Sour and Salty
15
Q
What flavors release ATP?
A
Sweet, Bitter, Umami
16
Q
NT release causes an AP in the sensory _______ axon
A
affarent
17
Q
T/F
Most taste cells respond to all five tastes
A
FALSE. It’s only one
18
Q
Some tastes cells (ex: 2) and affarent axons show _____ _____ preferences
A
broadly tuned (multiple taste-ants)
19
Q
Can the threshold for each tastant be determined?
A
YES.
20
Q
Which tastant has a lower threshold?
A
Bitter
21
Q
When are amiloride Na+ channels open?
A
ALWAYS
22
Q
Amiloride Na+ channels allow:
A
Na+ down concentration gradient
23
Q
Amiloride Na+ concentration gradient generates:
A
depolarizing recep. potential
24
Q
H+ concentrations go through _____ to inhibit ___ Channels, producing sour taste
A
proton channels ; K+
25
Sour taste causes ___ for the cell:
depolarization
26
Depolarization of Salt/Sour channels activate the ____ and ____ channels
Na+ ; Ca2+
27
After Salt/Sour tastes activate two channels, they release ____ (main NT)
Serotonin
28
Amiloride blocks what channel?
Na+
29
Sweet, Bitter and Umami have _____ _____ receptors:
G-coupled protein
30
T/F:
Sweet, Bitter and Umami have the same receptor types
FALSE
31
What does a G-protein activate?
phospholipase enzyme
32
IP3 binding releases:
Ca2+ from membrane storage centers
33
Internal Ca2+ stores are stored in:
ER with mitochondria
34
Ca2+ activated Na+ channels ____ the cell, causing ____:
depolarize ; ATP release
35
What does "dimer" mean:
two subunits are req. to bind tastant
36
Post. synaptiv gustatory afferent axons have _____ receptors
purinergic (ATP/GTP)
37
T/F:
Since both ATP/GTP are purines, that means they are both NT
FALSE. only ATP
38
IP3 binds to the
IP3 receptor
39
This taste receptor is the most diverse:
Bitter
40
Bitter recep. heterodimers of ___ and ____-
T1R ; T2R
41
For every bitter receptor, there is___ ____ and _____ ______ receptor
one sweet ; one umami
42
Sweet/Umami receptors are heterodimers of _____ and _____ subunits
T1R2 ; T1R3
43
Bitter compounds are more complicated because:
there is a wider broad of combinations
44
How many choices are there in the T1 receptor?
three
45
How many choices are there in the T2 receptor?
twenty-five
46
The sensory pathway to cerebral is:
taste bud prim. gust. axons -> brainstem -> thalamus -> cortex
47
How many combinations of the bitter tastant can we have?
75 (T1 3, x T2 25)
48
Gust. sensory neuron cell bodies in in ______ ganglia
sensory
49
The three cranial nerves that sense taste are:
1. VII (7)
2. IX (9)
3. X (10)
50
The three cranial nerves which receive taste info are ___-_____ sensory neurons
psuedo-unipolar
51
The gateway to cortex is:
thalamus
52
Pseudo-unipolar neurons send taste to the brainstem by:
1. receive input from tongue
2. transmit to 7, 9, 10 ganglia
3. project to gust. nucleus
4. into solitary tract nuc for b.stem
53
After taste received in brainstem, it goes to:
ventral posterior medial (VPM) of thalamus
54
After taste received in thalamus, it goes to:
primary gustatory cortex (frontal lobe, insular cortex in front, temp, par)
55
The central taste pathway is all _____ relative to cranial nerve
ipsilateral
56
Different parts of tongue represented by three dif. ganglia. Where, with what?
Front: 7
Middle: 9
Back: 10
*org lost in brain*
57
The VPM is part of what track in the brain:
internal capsule (white matter tract)
58
The gustatory afferent axon propagates signal to ganglia in ____ ____
geniculate ganglion
59
Two structures connected to gust. aff. axon:
1. nucleus solitary tract (NST)
2. geniculate ganglion CN 7 (primary sensory neuron ganglia)
60
Std. hierarchy for taste path (PNS):
1. medulla
2. NST
3. thalamus
4. gust. cortex
61
T/F:
Most cells in buds respond to many tastants
FALSE. Mostly one BUT a few which do many
62
Afferent cells detect ____ ____
multiple tastants
63
Afferent cells are (fine/broad) tuned to taste
BROAD (due to detect many)
64
The brain uses what approach for taste?
Population.
65
Why does the brain use pop. coding with taste signals?
there are many "broadly tuned" cells which encode tastants
66
What approach with tightly tuned cells in taste?
labeled line (overlapping populations)
67
What does the labeled line approach do for taste?
decide what you like and what you've had before
68
What approach does the sensory system use in taste?
population approach
69
T/F:
Separate regions in the brain are reserved for specific tastes
FALSE. Population coding means it's all over the brain
70
T/F:
Olfaction requires many molecules to respond
FALSE. You need only one because it's so sensitive
71
The olfactory epithelium is in:
the roof of your nasal cavity
72
The olfactory epithelium has:
olfact. receptor cells
73
T/F:
Olfactory receptors are found in all mammals
TRUE
74
Olfactoru receptors are ____ ____ neurons
bona fide
75
Olfactory receptors have ____ at the end
cilia
76
Cilia in receptors receive:
odors
77
Olfactory receptors have an axon which go to the ____ ___:
olfactory bulb
78
The olfactory bulb is under:
the brain (cribriform plate)
79
What cells are similar to glia, yet make mucus?
Supporting
80
Basal cells can generate new ____ ____ every few weeks
olfactory receptors
81
The volmeronasal organ is use for:
detection of social/sexual cues
82
T/F:
The CNS is diferent from the main olfaction pathway
TRUE, it goes to the ACCESSORY olfaction bulb (btw amygdala and hypothalamus)
83
The olfactory (epithelium/bulb) is larger in humans than rodents
bulb
84
The main olfactory signaling pathway has a mixture of what two things?
antibodies and proteins to receive odors
85
Odorant receptors detect what?
epitopes (chemical structure in odor)
86
Odors bind to receptors on what?
cilia
87
Odor receptors are _____
GPCRs
88
Since receptors are gene protein coupled receptors, they will sense what tastes?
Sweet, Bitter, Umami
89
What G-protein alpha subunit is found in olfact. cells?
G olf
90
G olf activates what?
adenylyl cyclase
91
Activation of adenylyl cyclase in the olfac. system increases what?
cyclic AMP (cAMP)
92
Production of cAMP in olfact. signal transduction opens what?
cAMP-gated channels
93
the opening of cAMP channels in the olfact. signal transduction allow for what?
Ca2+ and Na+ entrance
94
With olfac. signal transduction, entrance of two specific ions into the cell does what?
depolarizes cell
95
With olfac. signal transduction:
after Ca2+ is activated, what channels open?
Cl-
96
With olfac. signal transduction:
Once Cl- channels open, it causes what in the cell?
enhanced depolarization
97
With olfac. signal transduction:
Cl- effect on the cell creates what unique property?
Cl- is higher in than out
98
With olfac. signal transduction:
Cl- efflux enhances ______ caused by Na+ and Ca2+ influx
depolarization
99
With olfac. signal transduction:
what happens after prolonged odor exposure?
adaptation
100
With olfac. signal transduction:
Cl- effect on the cell does what to equilibrium potential?
Flips it. Likes to be negative (-65mV) but becomes positive
101
What two scientists found the olfactory organization system?
1. Richard Axel
2. Linda Buck
102
Odorant receptors are encoded by the largest ______ _____
gene superfamily
103
What gene superfamily encodes odors?
OR
104
T/F:
Each olfac. receptor neurons expresses many receptors
FALSEEEE!!! FALSE FALSE FALSE FALSE. They express ONLY one
105
T/F:
Each receptor protein can bind to multiple odor molecules
TRUE. The proteins are not very exclusive
106
Many cells which express the same receptor gene are _____ throughout the epithelium
Scattered (in zones)
107
What does it mean if an odor is TAAR (trace amine-associated receptor)?
detects volatile amines (V1-V2)
108
Each olfac. recep. cell expresses a ______ ______ _____ _____
single odor receptor protein
109
Different odor cells are _____ ____ within the epithelium
randomly scattered
110
An odor receptor cell can respond to different odors but what happens?
It has preferences
111
By measuring several receptor cell types, you can do what?
distinguish each odor
112
What is the central olfac. path for primary olfac. recep. cells?
Go to cribriform plate, enter bulb
113
T/F:
Receptor cell axons have one branch with many dendrites of first order cells
FALSE ; there are many branches/synapses with second order dendrites
114
Second order cell dendrites called:
mitral cells
115
Can we map smell?
YES! With the glomerulus, reveals encoded cells
116
Axons of olfac. recep. cells make contact with dendrites in:
the glomerulus
116
Olfactory receptor cells have (population/lined) coding
population
117
In the glomerulus, the cells have axons of ____ and dendrites of ____-
sensory neurons, mitral cells
118
Some odor receptors in the same glomerulus are ____ ____ in the two bulbs
bilaterally symmetrical
119
Primary olfactory recep. axons converge on:
one glomerulus
120
Lateral inhibition helps to:
sharpen light and dark boundaries in visual field
121
GABAergic granule cells in the olfactory bulb help:
distinct odor repsonse of mitral cells
122
Lateral inhibition is important in:
processing senses
123
Second order mitral neurons prohect to:
olfactory cortex (temporal lobe)
124
T/F:
Odor projection to the temporal lobe is unique to olfaction
TRUE. Usually it goes to the thalamus, then the cortex
125
In central olfactory pathways, odors projected directly to the olfactory cortex (temporal lobe) then go to: (2)
1. amygdala
2. entorhinal cortex
126
How do odors deal with social/emotional behavior?
Once signal projected from olfactory cortex, it goes to amygdala and entorhinal cortex which helps elicit response.
127
Where can mitral cells also project to (besides olfac. cortex)?
olfac. tubercle
128
Once odor signals are projected to tubercle, it goes to what two places?
1. thalamus
2. orbitofrontal cortex
129
In the tubercle -> thalamus -> orbito cortex circuit, what does this likely do?
mediate conscious perception of odor
130
List the order of the two different central olfactory pathways:
1. Olf bulb > Prim. olf cortx > Amy/Ento
2. Bulb > tuber > Thala > Orbito FC
131
the Olf Cortex is in the _____ part of _____ lobe
Rostro-dorsal part of temporal
132
Where in the brain are taste buds represented?
rostro-ventral part of parietal lobe
133
Gustatory and Olfactory cortices are _____ _____ at three major cortical lobe borders
close together
134
Resume slide 28
yessir
135
Neuro 3000
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