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