Gustation Flashcards
1
Q
What are the 5 human tast classes?
A
- Salty - proper electrolyte balance
- Sweet - energy rich nutrients
- Umami - amino acids
- Bitter+Sour - potentially noxious or poisonous
- Fatty? - satiety, combination of somatosensory and gustation
2
Q
What are the three types of papillae on your tongue?
A
- circumvallate
- foliate
- fungiform
3
Q
Describe taste buds
A
- Onion shaped structure containing 50-100 tast receptor cells
- Pore opens out to the surface of the body
- Apical surface - folded into microvillli (increase SA)
4
Q
What is the inability to tast called?
A
Ageusia
5
Q
Describe signal transduction for salty tastes.
A
- Na+ in mouth increases
- Membrane potential depolarizes
- Ca2+ channels opened/NT release
6
Q
Describe signal transduction for a sour taste.
A
- Apically localized K+ channels blocked by protons
- Receptor comprised of two parts
- TRPP3 and PDK1L3
- Results in depolarization and opening of Ca2+ channels
8
Q
Which 3 tast classes activate the phospholipase C pathway and are G protein coupled?
A
Sweet, umami and bitter
9
Q
Which GPRC do sweet tastants bind to?
A
T1R2, T1R3
10
Q
Which GPRC do umami tastants bind to?
A
T1R1, T1R3
11
Q
Which GPRC do bitter tastants bind to?
A
T2R
12
Q
A
13
Q
Which pathway is activated by L-glutamate and other amino acids as well as MSG?
A
Umami
14
Q
Describe the mechanism/pathway that sweet, bitter and umami tastants induce.
A
15
Q
What are the three major classes of taste cells?
A
- Type I glial cell
- Type II receptor cell (ATP release, sweet/umami/bitter)
- Type III presynaptic cell
16
Q
Why does airplane food taste awful?
A
- Dryness and low pressre decrease our abilities to taste (sweet, salty)
- Loud noises also decrease ability
- Low humidity means that we are able to smell poorly
