Chemical Senses 1 (Taste) Flashcards
1
Q
These differ for each taste
A
Threshold levels needed for response
2
Q
Gustatory nucleus neurons communicate with the VPM of the thalamus which projects here
A
Primary gustatory cortex
3
Q
The two mechanisms for salt detection
A
Amiloride sensitive and amiloride insensitive
4
Q
This inhibits sweet sensitivity
A
Leptin
5
Q
These tests sweeter than sucrose (table sugar)
A
Proteins, aspartame
6
Q
Many animals systems (cats, fish, salamanders, mice, and rats) were used to study this
A
Taste
7
Q
These synapse onto basal cells via electrical and chemical synapses
A
Taste receptor cells
8
Q
These enhance sweet sensitivity
A
Endocannabinoids
9
Q
These are mostly sensitive to one taste
A
Taste cells
10
Q
These are thought to be stem cells to replace taste cells
A
Basal cells
11
Q
Neurons that send taste info to the brain
A
Gustatory afferent neurons (sensory)
12
Q
Low salt (10-150 mM) tastes this way
A
Good
13
Q
What tastes do we like/dislike?
A
Like sweet, dislike bitter
14
Q
Just like sweet and bitter, this activates a second messenger system (GPCR)
A
Umami
15
Q
Mutations in this affects the vestibular system
A
OTOP1
16
Q
These affect the taste of salts in the amiloride insensitive mechanism
A
Anions
17
Q
These neurons penetrate taste buds
A
Sensory gustatory neurons
18
Q
These lead to the medulla, thalamus, and cortex
A
Gustatory axons
19
Q
This is released in salt detection
A
5HT
20
Q
Some taste cells only express bitter receptors and have some communication to these
A
Gustatory axons
21
Q
Has a low pH and type III presynaptic cells respond to it
A
Sour
22
Q
In type II cells, sweet, bitter, and umami tastants do this
A
Active second messenger systems which interact with ion channels and lead to NT release
23
Q
This declines with age
A
Gustatory sensitivity
24
Q
What are taste receptors likely doing all over the body?
A
Gathering info about some sugar produced by a bacteria or something that shouldn’t be there
25
What are the 5 tastes?
Sweet, salt, bitter, sour. umami
26
These stick out from the taste receptor cell into the taste pore to be exposed to tastants
Microvilli
27
Taste sour bc of proton detection
Acids
28
This taste uses T1R1+T1R3 receptors (type II)
Umami
29
These detect many molecules and structures
Taste receptors
30
Detect environment, signals integrated in orbitofrontal and other cortical areas
Taste (gustation) and smell (olfaction)
31
When are labeled lines and population coding seen in neural coding of taste?
Labeled lines at the beginning with taste cells and axons being specific to one but pop coding seen later in the cortex
32
This is both salty and bitter
K
33
Sweet receptors
T1R3
34
Channels are open all the time to depolarize the cell during this taste detection
Salt
35
Most taste reception is here
Tongue
36
Influences many feeding behaviors (vomiting, swallowing, digestion, breathing), mediated by other areas of the brain such as the medulla and hypothalamus
Taste info
37
How many taste buds are there on average? Whats the range?
2000-5000 avg. 500-20000 range
38
How often is taste cell sensitivity to one of the five tastes replaced?
Every 10-14 days
39
Rich in proteins/amino acids. Delicious, MSG or glutamate, nucleotides
Umami
40
How do the thresholds for salt/sweet compare to those for bitter (how do the sensitivities compare)?
High threshold for salt/sweet, low for bitter. (Bitter is in uM while salt/sweet is in mM)
41
Uses a combination of labeled lines (one responds to one) and population coding (one responds to many, many respond to one)
Taste neural coding
42
Many poisons are this taste
Bitter
43
Taste bud cells that are close to gustatory afferents but have no synapses or synaptic vesicles, no VG calcium channels
Type II
44
At least 30 of these genes are used to recognize bitter, depends on the species/person
T2R
45
Many areas of the tongue are sensitive to these
All basic tastes
46
These are important for hunger, emotion, sex, and memory
Chemical senses
47
Signal mechanisms can be influenced by these to do things like enhance or inhibit sweet sensitivity
Signals like leptin and endocannabinoids
48
These open with low pH and are H permeable
OTOP1
49
Taste bud cells that use GPCRs
Type II
50
Bitter receptors
T2R
51
We crave these when they are lacking
Nutrients
52
In type II cells, salt and sour tastants pass through these
Ion channels
53
Good markers for sour sensitive cells
PKD2L1 and OTOP1
54
The more important sour sensing receptor
OTOP1
55
The heteromeric dimers that make up umami receptors that detect some umami tastants
T1R1+T1R3
56
Some of these cells also synapse onto taste receptor cells
Basal cells
57
This is selectively expressed in a unique pop of taste bud cells (type III)
OTOP1
58
These are found in the stomach and intestine
Gustducin and T1R3 receptors (sweet)
59
The oldest (evolutionarily) and most universal
Chemical sense
60
Sour detecting cells allow protons to enter through a channel to inhibit and cause what?
Inhibit specific K leak channel and depolarize the cell
61
Used to determine what is food and what is poison
Taste
62
Multiple of these are in each taste cell (4-11) for bitter
T2Rs
63
Molecules being detected for taste
Tastants
64
Some cells detect both sweet and umami, but never these two combination
Bitter and umami or bitter and sweet
65
Where is the sensory part of a taste receptor cell
Apical end (facing out)
66
These are located on paella (bumps on tongue)
Taste buds
67
Taste bud cells that respond to sour taste
Type III
68
These are found in the stomach, intestines, and lungs
T2R receptors (bitter)
69
The transmitters taste cells use to generate receptor potentials and depolarize
5HT and ATP
70
How do most cells respond to taste? Is this always the case?
Most cells respond strongly to one taste but some can respond to more than one
71
How many basic tastes are there?
5
72
Each one of these uses one mechanism, not all are understood however
Each basic taste
73
The heteromeric dimers that make up sweet receptor cells that detect all sweet tastants
T1R2+T1R3
74
Are taste receptors exclusive to the mouth?
No, they are in the pharynx, lungs, intestines, testis, etc.
75
Taste bud cells tuned to detect one of three tastes (bitter, sweet, or umami)
Type II
76
Various ones of these are found in the heart, kidneys, testis, thyroid, and other organs/cell types including the brain
Taste receptors
77
How are taste cells dispersed on the tongue?
They are spread out and not located for specific tastes
78
Taste bud cells that are probably progenitors of other taste sensing cells
Basal cells (Type IV)
79
Monitor internal environment (O2, CO2, proteins, etc), involved in chemical communication and integration
Chemoreceptors
80
Each taste bud contains how many tase bud cells?
50-150 (1% of tongue epithelium)
81
A PLC and taste cell specific cationic channel
TrpM5
82
Activate the same second messenger system as for bitter using GPCRs
Sweetness (type II cells)
83
How do different tastes stimulate different responses in the brain?
They stimulate responses in different areas (insular taste cortex)
84
Brodmann's 36
Primary gustatory cortex
85
These cells are likely involved in salt detection
Type I and type III
86
Taste bud cells that are presynaptic, form synapses, have synaptic vesicles, and use VG calcium channels
Type III
87
This taste uses T1R2+T1R3 receptors (type II)
Sweet
88
Signals to the primary gustatory cortex are carried in this manner
Ipsilaterally, same side
89
This taste uses T2R receptors (type II) only
Bitter
90
This is detected by an mGluR for umami detection
Glutamate
91
High levels of salt are aversive and activate these cells
Bitter (type II) and sour (type III)
92
K, Mg, and caffeine all taste this way
Bitter
93
Both of these are needed for flavor detection
Taste and smell (gustation and olfaction)
94
The G protein present in some taste cells
Gustducin
95
Smell, combinations of receptors, pain, texture, visual cues, and temp all contribute to this
Flavor
96
No taste perception
Ageusia
97
The G protein used in sweetness
Gustducin and probably others
98
Taste bud cells like glial cells that may be Na+ sensing, but we aren't sure
Type I
99
Two families of taste receptor genes that are GPCRs (using gustducin) in type II cells for detecting bitter
T1R and T2R
100
Things with very different structures can have this taste
Sweet
101
These 3 cranial nerves carry gustatory axons
VII (facial), IX (glossopharyngeal), and X (vagus)
102
When exposed to chemicals, taste cells do this
Generate receptor potentials to depolarize
103
Where do gustatory axons first synapse?
Gustatory nucleus in medulla
104
Na+ enters through these channels
Amiloride sensitive Na+ channels (others probably involved like TRPV1 and TMC-1)
105
This NT is released by sour sensitive cells
5HT
