Lec 18/19 Flashcards

1
Q

Olfactory transduction mechanism in receptor cilia:

What happens following the binding of a G-olf protein with a odorant molecule?

A

the alpha subunit of G-olf in turn activates adenylyl cyclase, which produces cAMP.

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2
Q

What type of of receptor is associated with the olfactory transduction mechanism?

A

G-olf receptor

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3
Q

Olfactory transduction mechanism in receptor cilia:

what happens after the activation of the effector adenylyl cyclase and the production of its 2nd messenger?

A

cAMP binds to a cAMP-gated cation channel and by doing this, the channel increases permeability to Na, k, and Ca. this allows a net inward current and leads to the depolarization of the cell as well as Ca2+ increase

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4
Q

Olfactory transduction mechanism in receptor cilia:

What happens following membrane depolarization after the opening of the nonselective cation channel?

A

the increase in Ca2+ opens Ca activated Cl- channels which produce more depolarization because because of relatively high Cl concentrations of olfactory receptor neurons.

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5
Q

Olfactory transduction mechanism in receptor cilia:

What happens after the depolarization due to Ca2+ activated Cl- channels?

A

If the receptor exceeds the threshold, it triggers action potentials in the soma that travel down the axon and into the brain.

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6
Q

What are the 3 ways to terminate an Olfactory response?

A
  1. oderant diffuses away
  2. mucous layer enzymes break it down
  3. cAMP in receptor cell activates other signalling pathways.
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7
Q

What process depends on receptor potentials mediated through the effect of an environmental stimulus acting on a receptor molecule.

A

Sensory transduction

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8
Q

What are the 5 steps to the Sensory transduction pathway?

A

ERTRS

  1. Environment stimulus
  2. Receptor molecule
  3. Transduction channel
  4. Receptor potential
  5. spike train or Neurotransmitter release
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9
Q

what are the 4 types of sensory transduction?

A
(TMCV)
Thermoreception
Mechanoreception
Chemoreception
Visual transduction
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10
Q

Which type of Sensory transduction is involved with hearing and touch?

A

Mechanoreception

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11
Q

Which type of sensory transduction is involved with taste and smell.?

A

Chemoreception

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12
Q

What senses are involved with mechanoreception?

A

hearing and touch

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13
Q

What senses are involved with chemotransduction?

A

taste and smell

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14
Q

What types of sensory transduction channel produces a “transient” response ?

A

TRP channel

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15
Q

What does TRP stand for?

A

Transient receptor potential

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16
Q

Are TRP receptor channels selective or non selective? and if so what are they selective to?

A

not selective and sometimes can be permeable to Ca

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17
Q

What are the “feelings” or sensations that are involved with TRP channels?

A
PIHTT "PIT"
Pain
itch
heal
taste
touch
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18
Q

TRP channels can be activated or modulated by what range of environmental stimuli?

List:

A
TIP2M 
temperature
ph
mechanical stress
interaction with chemicals
2nd messengers
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19
Q

What is the abbreviation for the “vanilloid” subfamily?

A

TRPV

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20
Q

What is the abbreviation for the “classical” subfamily?

A

TRPC

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21
Q

What is the abbreviation for the “melastatin” subfamily?

A

TRPM

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22
Q

What is the abbreviation for the “ankyrin” subfamily?

A

TRPA

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23
Q

How will A warmth thermoreceptor that experiences slow increasing change in temperature adjust its firing rate?

A

increase in fire rate

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24
Q

How will A cold thermoreceptor that experiences slow increasing change in temperature adjust it’s firing rate?

A

increase in fire rate

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25
Q

Which type of thermoreceptor has a broader temperature response?

A

cold receptors

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26
Q

At what temperature does a cold receptor reach its max firing rate?

A

~25ºC

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27
Q

At what temperature does a hot receptor reach its max firing rate?

A

~46ºC

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28
Q

Are all neurons sensitive to temperature?

A

yes

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29
Q

What is the diameter of the small areas on your skin that are sensitive to changes in temperature?

A

1mm

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30
Q

T or F : A single thermoreceptor will be sensitive to both heat and cold.

A

False; they either cold or heat receptors.

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31
Q

What type of receptor is most likely free nerve endings?

A

thermalreceptors (cold and warm)

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32
Q

thermosensation is likely to be mediated by ______ channels. This was discovered due to tissue cultures.

A

ion channels

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33
Q

What are the mammalian thermal sensitive channels?

A

TRPV1-4 (1 is most important)
TRPM8
TRPA1

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34
Q

What activates the thermosensitive channel TRPV1?

A

capsaicin

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35
Q

capsaicin activates which thermosensitive channel?

A

TRPV1

36
Q

the pungent “hot” ingredient in chilly peppers is due to what ingredient?

A

capsaicin

37
Q

What activates the thermosensitive channel TRPM8?

A

menthol

38
Q

menthol activates which thermosensitive channel?

A

TRPM8

39
Q

The cool mint-like compound that activates channels in thermoreception is called..

A

menthol

40
Q

What thermosensitive channel(s) respond to heat?

A

TRPV1-4

41
Q

What thermosensitive channel(s) respond to cold?

A

TRPM8, TRPA1

42
Q

Which thermosensitive channels have a higher threshold?

A

Heat responsive

TRPV1-4

43
Q

Which thermosensitive channels have a lower threshold?

A

Cold responsive

TRPM8, TRPA1

44
Q

Which thermosensitive channel is activated by a wide range of compounds including garlic and cinnamon ?

A

TRPA1

45
Q

What 2 Thermosensitive channels are activated by the substance icilin?

A

TRPA1, TRPM8

46
Q

HEAT OR COLD?

activation of the channel is more sensitive

A

heat

47
Q

HEAT OR COLD?

activation of the channel is less sensitive

A

cold

48
Q

What are the names of the 2 different vestibular hair cells?

A

Type I and Type II

49
Q

What type of cells are “hair cells”

A

modified endothelial cells

50
Q

What are the 2 vestibular extracellular solutions called?

A

vestibular endolymph and paralymph

51
Q

what is the potential of Endolymph?

A

0 mV

52
Q

What is the potential of Paralymph?

A

0mV

53
Q

What are defined as vestibular hair bundles?

A

Stereovilli

54
Q

What is the voltage of a Vestibular type I cell?

A

-40mV

55
Q

What is the voltage of a Vestibular type I cell?

A

-40mV

56
Q

In the Vestibular system, what type of hair cells has a calyx-shaped afferent nerve terminal?

A

Type I cell

57
Q

In the Vestibular system, what type of hair cells several bouton-shaped afferent nerve terminals?

A

Type II cell

58
Q

In the Vestibular system, what type of hair cells has a bulbous basal area?

A

Type I cell

59
Q

In the Vestibular system, what type of hair cells has a more cylindrical shape?

A

Type II cell

60
Q

is there a high K+ concentration inside or outiside a type II vestibular hair cell?

A

inside

61
Q

What are the tallest Stereosillia called?

A

Kinocillium “true cillium”

62
Q

The K+ concentration is higher in which venstibular solution?

A

endolymph

63
Q

Deformation of stereovilli in one direction cause opening of what type of channels?

A

TRPA1 channels

64
Q

Deformation of stereovilli in the direction of the kinocillium causes…..

A

K+channels to open (in stereocillia)

65
Q

K+ influx in stereocilli is caused by mechanical deformation in what direction?

A

toward the kinocillium

66
Q

Deformation of stereovili away from the kinocilliu causes…

A

K+channels to close

67
Q

In vestibular hair cells, what happens to the firing rates during a quick response?

A

firing rates increase

68
Q

Ca2+ concentration is higher in which vestibullar solution?

A

paralymph

69
Q

During Vestibular hair cell depolarization there is a Ca influx which leads to..

A

NT release

70
Q

Vibration of stereovilli leads to rapid fluctuation in what 3 things?

A
  1. membrane potential
  2. Intracellular Ca
  3. transmitter release
71
Q

the channels are the tips of stereocilli are selective or non selective?

A

nonselective

72
Q

The closing of channels on the stereocilli causes …

A

hyperpolarization

73
Q

Measurements of Ca2+ influx due to GFP showed that mechemoreceptive channels are located where?

A

close to the bottom of the “link tips” on the stereovilli

74
Q

When a link tip is pulled with tension what happens?

A

the entry of Ca2+ and other ions!

75
Q

What are the 5 primary taste qualities?

A
SS SUB
sour
salty
sweet
umami
bitter
76
Q

The taste of salt is due to what substance?

A

Na+ directly

77
Q

The sour taste is due mainly to what substance?

A

acids or H+ protons

78
Q

The Umami taste is due mainly to what substance?

A

amino acids

79
Q

Which has a more diverse range of stimuli? taste or smell?

A

smell 400,000 oderants

80
Q

a taste receptor is what kind of cell?

A

modified endothelial cell

81
Q

Taste receptors as well as vestibular hair cells are what type of cells?

A

modified endothelial cells

82
Q

each taste bud contains how many taste cells?

A

50-100 taste cells

83
Q

Taste reception always depends on the release of what ion for the release of NT?

A

Ca2+

84
Q

In taste cells, how is specificity acheived?

A

taste cells express only one type of transduction system linked with single sensory neurons.

85
Q

What are the 2 types of taste buds?

A
  1. Salty & Sour

2. Sweet , Umami, and Bitter

86
Q

Which taste sensation is due to Na+ levels in the saliva and uses the EnAC channels?

A

Salty