chemical senses Flashcards

1
Q

what is the role of hypothalamus and amygdala in human taste system

A

pleasure, aversion, food seeking, satiety, etc.

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2
Q

cranial nerve for epiglottis

A

10

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3
Q

taste in the fungiform papillae

A

sweet, umami

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4
Q

taste in the circumvallate papillae

A

bitter

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5
Q

foliate papillae taste

A

salt and sour

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6
Q

nerve for circumvallate papillae

A

9

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7
Q

cranial nerve for fungiform papillae

A

7

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8
Q

describe the makeup of papillae

A

contain a few 100 taste buds, each taste buds have 50-100 taste receptors,

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9
Q

are taste receptor cells neurons

A

no

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10
Q

what do taste receptor cells synapse on

A

gustatory afferent axons

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11
Q

which tastes have smaller taste thresholds

A

bitter and sour

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12
Q

what is the taste transduction cascade for umami

A

tastants activate T1R1 and T1R3, alpha subunit activates PLCB2 which transforms IP3 from PIP2, IP3 opens a Calcium channel on the endoplasmic reticulum which releases calcium into the cytoplasm, calcium influx opens TRPM5 channel causing Na influx, robust depolarization occurs, Calcium modulator channel is opened from the intracellular calcium, ATP is released, PX2/PX3 channels open as a result of ATP as neurotransmitter on the taste nerves

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13
Q
A
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14
Q
A
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15
Q

what is the taste transduction pathway for salty

A

amiloride sensitive sodium channels open due to salt tastants, depolarization occurs and flows downstream where it activates voltage-gated sodium, potassium, and calcium gated channels, calcium allows for transmitter release onto the taste afferents

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16
Q

what is the taste transduction pathway for sour

A

hydrogen sensitive TRP channels open in response to sour tastants, the depolarization travels downstream to open sodium, potassium, and calcium channels, the channels result in more depolarization and stimulate neurotransmitter release onto the taste afferents

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17
Q

what is the central taste pathway

A

taste buds, gustatory axons, medulla/brain stem, VPM thalamus, insular/frontal cortex, amygdala

18
Q

where are the collateral inputs of the medulla

A

hypothalamus and amygdala

19
Q

what happens if you ablate the P2X receptors

A

taste cells cannot depolarize and you cannot taste anything

20
Q

describe olfactory transduction

A

receptor binds odorant, alpha subunit turns gtp to gdp, adynyl cyclase activated, camp synthesized, camp channels opened for na and ca causing influx, calcium binds to ca gated cl channel causing an influx of cl, cell is further depolarized (most of depolarization

21
Q

describe olfactory repolarization

A

calcium begins to inhibit adynyl cyclase which decreases camp synthesization and decreases camp affinity of camp gated channels so some begin to close (by binding to CAM)

22
Q

what kinds of inputs do each glomerulus receive

A

each glomerulus receives input from olfactory neurons expressing specific receptor proteins

23
Q

describe the central olfactory pathways

A

olfactory receptor neurons synapse on the mitral and tufted cells in the glomureli (these make up the olfactory tract in the olfactory bulb). the olfactory tract extends to the pyriform cortex, olfactory tubercle, amygdala, and entorhinal cortex
-these project to the orbitofrontal cortex, thalamus, hypothalamus, and hippocampus

24
Q

what is the role of DAG in bitter sweet umami pathway

A
25
Q

what is the role of melastatin in sween umami pathway

A
26
Q

what g protein receptor is associated with bitter

A

T2R

27
Q

what g protein receptor is associated with sweet

A

T1R2, T1R3

28
Q

what g protein receptor is associated with umami

A

T1R1, T1R3

29
Q

what tastes is the TRPM5 channel associated with

A

bitter, sweet, umami

30
Q

how many types of T2R channels are there

A

30, most bitter taste receptor cells express most of them if not all

31
Q

where are the foliate papillae

A

sides of tongue

32
Q

where are the circumvallate papillae

A

back diamond of tongue, nine of them

33
Q

where are the fungiform papillae

A

front of tongue

34
Q

what is the most sensitive part of the olfactory receptor cell

A

the cillia

35
Q

what do we know about the loss of smell with covid 19

A
36
Q

what is the significance of temporal spiking

A
37
Q

where is the olfactory bulb

A

bottom of the frontal lobe near your nose

38
Q

what flavor corresponds to the glutamate tastant

A

umami

39
Q

what flavor corresponds to the quinine tastant

A

bitter

40
Q

what flavor corresponds to the sucrose tastant

A

sweet