07b: Taste and Smell Flashcards

1
Q

Both taste and smell receptors are stimulated by:

A

molecules (in solution)

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2
Q

Taste receptors are grouped together as (X), which are found in (Y).

A
X = taste buds
Y = papillae
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3
Q

List the cell types found in one taste bud.

A

Types I and II: supporting cells (with microvilli)
Type III: sensory receptor
Type IV: basal cell

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4
Q

Basal cells found in taste buds come from (X) and are important for (Y).

A
X = migration of surrounding epithelium
Y = production (via differentiation) into new sensory receptor cells
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5
Q

T/F: there is continual turnover of sensory receptors in taste cells.

A

True

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6
Q

List taste regions on tongue, from distal to proximal.

A
  1. Sweet
  2. Salty
  3. Sour
  4. Bitter
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7
Q

Taste molecules interact with (ion channels/GPCR). All stimuli elicit (increase/decrease) in (X).

A

Either;
Increase
X = intracellular Ca

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8
Q

Gustducin is a(n) (X) involved in which specific sensations?

A

X = GPCR

Sweet and bitter(2) tastes

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9
Q

T/F: Gustducin AA sequence and biochemical properties are similar to rod transducin.

A

True

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10
Q

Salty taste is result of (X) ion, which (depolarizes/hyperpolarizes) taste cells by:

A

X = Na
Depolarizes;
Passive influx through amiloride-sensitive Na channels

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11
Q

Na entering taste cell does so through (passive/active) transport through (X), located on (apical/basal) surface of cell.

A

Passive;
X = amiloride-sensitive Na channel
Apical

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12
Q

How is proper Na and (X) ion concentration maintained in taste cell?

A

X = K

Na/K pump in basolateral membrane

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13
Q

Sour taste is produced by (X). Degree of “sourness” depends on (Y).

A
X = acids;
Y = proton concentration
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14
Q

T/F: Sour(1) and Sour(2) involve similar mechanisms in depolarization of taste cell.

A

False

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15
Q

Sour(1) mechanism of (depolarization/hyperpolarization).

A

Depolarization;

Blocks K efflux from cell

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16
Q

Sour(2) mechanism of (depolarization/hyperpolarization).

A

Depolarization;

Influx through amiloride-sensitive Na channels

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17
Q

List the ion(s) that pass through amiloride-sensitive (X) channels in taste sensation.

A

X = Na

Na and H

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18
Q

Bitter sensation is mostly elicited by (X). Give an example.

A

X = poisonous/toxi plant substances;

Quinine or CaCl2

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19
Q

T/F: Bitter(1) and Bitter(2) involve two different GPCR.

A

False - Bitter(1) doesn’t involve GPCR

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20
Q

T/F: Bitter(1) and Sour(1) involve similar mechanisms in depolarization of taste cell.

A

True

21
Q

(X) taste(s) involve gustducin, which (activates/suppresses) (Y). The key second messenger is (Z), which mediates:

A

X = bitter(2) and sweet;
Activates;
Y = PLC
Z = IP3

Ca release from intracellular stores

22
Q

T/F: All sweet taste transduction mechanisms use GPCR.

A

True

23
Q

Sweet taste mechanism involves activation of (X), which immediately stimulates:

A

X = Gustducin

Either AC or PLCd

24
Q

(X) molecule elicits the unique umami sensation, which involves (Y) receptor.

A
X = L-gluatamate
Y = metabotropic glutamate receptor
25
Q

Main ingredient that makes food hot/spicy is (X), the receptor for which is (ion channel/GPCR) for both (X) and (Y).

A

X = caspaicin;

Ion channel

Y = painful heat stimulation

26
Q

When activated by caspaicin or by (X), the receptor causes:

A

X = heat;

influx of Ca and Na ions

27
Q

Taste sensory cells have axons that synapse on:

A

They don’t have axons!

28
Q

Mature olfactory receptor has long, thin (X) that terminates in (Y) which gives rise to about 5 (Z).

A
X = dendrite;
Y = knob
Z = cilia
29
Q

(X) processes on ends of olfactory receptors lie in thin layer of (Y), secreted by (Z) cells.

A
X = cilia;
Y = mucus
Z = supporting
30
Q

Olfactory receptors arise from maturation of (X) cells.

A

X = basal

31
Q

Olfactory molecules diffuse through (X) and reach/bind specific receptors in plasma membrane of (Y).

A
X = mucus;
Y = cilia
32
Q

Binding of olfactory molecule to receptor on (X) initiates (rapid/gradual) (activation/suppression) of (Y) and formation of (Z).

A

X = cilia;
Rapid activation;
Y = G-proteins Golf, then AC
Z = cAMP

33
Q

In olfactory sensation, production of (X) is key to (opening/blocking) (Y) channels, resulting in:

A

X = cAMP;
Opening;
Y = cyclic NT-gated (CNG)

Influx of Na and Ca (depolarization)

34
Q

In olfactory sensation, the influx of (X) ions causes both (depolarization/hyperpolarization) and (opening/closing) of (Y) channels. What effect does this have?

A

X = Na and Ca;
Depolarization;
Opening;
Y = Ca-gated Cl channels

Efflux of Cl out of cell and further depolarization

35
Q

Olfactory sensation: when (de/hyper)-polarization of (X) spreads to (Y), action potentials are conducted to the first relay station, (Z).

A

Depolarization;
X = cilia;
Y = cell body;
Z = olfactory bulb (mitral cells)

36
Q

(High/low) intracellular concentration of (X) has been shown to play role in odor sensitivity regulation by directly (activating/suppressing) (Y).

A

High;
X = Ca
Activating;
Y = Calmodulin

37
Q

Odor desensitization is a result of desensitization of (X) channels by (Y).

A
X = cAMP-gated (CNG) 
Y = Ca-calmodulin complex
38
Q

A given olfactory receptor shows (narrow/broad) spectrum of sensitivity to different odors - about (X) number.

A

Broad;

X = 10-12

39
Q

Primary afferent neurons in olfactory system are (X). Where are second order neurons?

A

X = olfactory receptor cells;

Mitral cells (in olfactory bulb) are second-order neurons

40
Q

About (X) number of olfactory afferent fibers synapse on one mitral cell.

A

X = 1000

41
Q

Olfactory receptors respond to prolonged stimulation with (slow/fast) adaptation.

A

Slow

42
Q

Adaptation to orders is likely due to (central/peripheral) neural property in olfactory pathway.

A

Central (inhibitory interactions)

43
Q

T/F: Olfactory bulb is recipient of many afferent inputs from the brain.

A

True

44
Q

Individual olfactory receptors respond to (one/many) types of odorants, and have (same/different) responses to the same odorant.

A

Many; different

45
Q

Regardless of specific taste type, they all cause (depolarization/hyperpolarization) that causes (X), which causes (Y), which causes (Z).

A

Depolarization;
X = Action Potential;
Y = Ca influx
Z = NT release

46
Q

T/F: All taste receptors that activate GPCR are involved in releasing Ca from intracellular stores.

A

False

47
Q

T/F: Salt taste receptor is open at rest.

A

True

48
Q

One form of sweet activates AC. What’s the pathway after that?

A
  1. Produces cAMP
  2. Activates PKA
  3. Phosphorylation/blocking K channels on basolateral membrane
  4. Depolarization
49
Q

Which tastes cause eventual release of Ca from intracellular stores?

A

Sweet and bitter(2)