7.3: Sensing Temperature and Taste Flashcards
temperature fibers are typically:
C and AS fibers, like nociceptors
which channels are temp sensitive?
transient receptor potential channels (TRPCs)
capsaicin receptor/ hot temp receptor
TRPV1
medium heat receptors
TRPV3/ TRPV4
channel that opens in response to cold temp
TRPM8
channel that opens in response to NOXIOUS cold
TRPA1
Why can a person adapt to spicy diets?
because their TRPV1 capsaicin/hot temp channels gets deactivated after prolonged stimulation
menthol causes ____ to open at higher temps. Makes things taste cool even at regular temps
TRPM8
each tastebud houses ___ ___
taste cells
each tastecell on a tastebud houses taste ___
receptors (GPCRs)
activation of GPCR taste receptors release ___ onto ___ ___ that project to ___ ___ ____
activation of GPCR taste receptors release ATP onto SENSORY AXONS that project to NUCLEUS TRACTUS SOLITARIUS
T1 receptors have affinity for
sweet or umami.
T2 receptors have affinity for
bitter
activation of a taste receptor recruits the ____ gProtein.
gustducin
how does the gustucin in the taste cell receptor activate sensory neurons
has 2 subunits: alpha unit activates phosphodiesterase
beta subunit activates PLC
Ca2+ influx due to Gustducin activation opens TRPM5 channel (cation channel)
which T1 receptor couples are sensitive to sweetness? to umami?
T1R2+T1R3 = sugar affinity
T1R1 + T1R3 = umami affinity (sensitive to MSG)
the ____ channel receptor responds to acidity
PKD2L1
Why can PKD2L1 channel open in response to CO2?
because there is carbonic anhydrase surrounding it and it converts CO2 to H+ and HCO3-
Which channel detects salt? Where are these channels present?
epithelial Na+ channel. Present in the taste cells and kidney. when Na+ in ECF, epithelial channels open and Na+ flows into the cell, depolarizing it
____ involved in sensing presence of fatty acids
CD36
___ is the principle gustatory neurotransmitter
ATP
what happens when ATP is released by the taste receptors?
when gustatory sensory neurons bind ATP, P2X receptor channel opens and + flows into axon terminal.
taste receptors release atp onto sensory neurons, which project to ___ ___ __ in the ____. this region can project into 3 other regions. what are they?
nucleus tractus solidarius in the medulla. NTS can project into amygdala, primary gustatory cortex for cognitive interpretation of taste, and portions of the thalamus for appetite regulation
3 cranial nerves that gustatory senses are conveyed to the brain through
1) Facial nerve: conveys info from tip of tongue
2) Glossopharyngeal nerve: innervates rest of the tongue
3) Vagus nerve; innervates buds on the roof of mouth
