Taste
Where are taste buds located
In the papillae of the tongue
Bitter tastes are ______ aversive
Innately
The Na+ channels are voltage ______ and are blocked by
Insensitive and are blocked by the diuretic amiloride
What do salt and sour tastes reli on
Ion channels
Sour taste is produced by the _____ concentration of _____ in acidic foods
Sour taste is produced by the high concentration of protons in acidic food
What taste is mediated via GPCRs
Sweet Bitter Umami
Which receptors are used for Sweet taste Bitter Taste Umami taste
Sweet —> T1R2 + T1R3 Umami —> T1R1 + T1R3 Bitter = T2R
What does the gustatory detect
Tastants
Order of synapses for taste 1st order axons 2nd order axons 3rd order axons
1. Synapse in the medulla in the nucleus solitarius - 2. Synapse in the VPM of the thalamus 3. Synapse in the gustatory cortex
Tastant receptors go to ion channels via ____ ______ pathways and involve ______
2nd messenger pathways and involved GPCRs
What does each cranial target CN 7 CN 9 CN 10
7 —> anterior 2/3 of tongue 9 —> posterior 2/3 of tongue 10 —> other taste buds
Salt entering the cell and causing depolarization is an ______ response
Appetive
Increasing salt conc. Transforms innately appetitive stimulus to an ______ stimulus
Aversive
Afferent nerve fibers (cranial nerves involved)
CN 7 CN 9 CN 10
Main type of papillae
Circumvallate
The role of the TRPM5 channel
Depolarized the taste cell via increased Ca+ in the cell
Taste system is also called the ______ system
Gustatory
Salt receptor mediation (pathway)
Na+ ions enter the receptor cells via Na+ channels and the cell depolarizes
GPCRs act through _____ and _____ to do what?
PLC and IP3 to release Ca+ and open the TRPM5 channel
Explain what happens with sour taste
Protons (H+) block the K+ channels which causes depolarization of the cell H+ flows in and increase the pH and K+ ions cant move in or out so this causes a depolarization of the cell and opens Na+ channels and then Na+ ions move in and causes an action potential and Ca+ ions move in via Ca+ channels
Are taste buds in the stomach, gut and pancreas
Yes
