chemical senses Flashcards
1
Q
chemoreceptors
A
monitor internal environment, chemical communication and integration
2
Q
chemoreceptors are important for…
A
hunger, emotion, sex and memory
3
Q
5 basic tastes
A
sweet sour salty bitter umami (savory)
4
Q
T or F: aspartame is sweeter than sucrose
A
TRUE
5
Q
what tastes bitter?
A
K+ (also salty), Mg2+, caffeine
6
Q
apical end
A
sensory part of taste receptor cell
7
Q
taste receptors cells synapse with..
A
gustatory afferent axons and basal cells
8
Q
T or F: most cell respond to one taste
A
TRUE
9
Q
saltiness mechanism
A
- Na+ enters through amiloride-sensitive Na+ channels
- open all the time, depolarizes taste cell
- anions affect the taste of salts
10
Q
sourness mechanism
A
- lower pH (acid)
- H+ enters H+sensative TRP channl (PKD2L1), depolarizes cell
- selectively expressed in unique population of TRC’s
11
Q
bitterness mechanism
A
- two families of receptor genes, T1R and T2R, these are G-protein coupled taste receptors
- 30 T2R genes used to recognize bitter
- PLC and taste cell specific cationic channel
12
Q
sweetness mechanism
A
- many different tastants, ALL detected by the same receptor
- T1R2 + T1R3 (heteromeric dimers)
- activate same second messenger system as bitter
13
Q
umami mechanism
A
- amino acids
- T1R1 + T1R3
- activate same second messenger as bitter
14
Q
ageusia
A
no taste perception
15
Q
central taste pathway
A
- cranial nerves VII (facial), IX (glossopharyngeal), and X (vagus) carry gustatory axons
- gustatory axons lead to medulla, thalamus, and cortex
- gustatory to VPM thalamus to primary gustatory cortex (brodmann’s 36)
- IPSILATERAL
