Taste Smell Physio

Question 1

What NT do SUB release?

Answer 1

ATP

Question 2

What NT do salty/sour release?

Answer 2

seratonin

Question 3

What is the mech for salty sensory cells?

Answer 3

• salt binds ENaC, increases Na in saliva and on the tongue
• Na diffuses down gradient into cell,
• DEPOL causes increase in intracellular Ca
• 5HT released

Question 4

What is the difference in mech between salty and sour?

Answer 4

• excess H+ (acid) inhibits K channels from flooding additional positive charge into cell
• DEPOL causes increase in intracellular Ca
• 5HT released

Question 5

What is the mech for sweet/bitter sensory cells?

Answer 5

• sugars bind Gq, activates PLC-IP3
• increase in intracellular Ca activates TRPM5, Na floods in
• DEPOL causes release of ATP thru Panx1 channels

NOTE: bitter molecules bind GPCR with very high affinity (we are sensitive to it)

Question 6

What is the difference in mech between sweet and umami?

Answer 6

• Glutamate binds mGluR4***, activates PLC-IP3
• increase in intracellular Ca activates TRPM5, Na floods in
• DEPOL causes release of ATP thru Panx1 channels

Question 7

What processes taste on anterior 2/3 of tongue?

Answer 7

chorda tympani branch of facial nerve, with cell bodies in geniculate ganglion
- terminate in nucleus tractus solitarius (gustatory/rostral area)

Question 8

What processes taste of posterior 1/3 of tongue?

Answer 8

lingual branch of glossopharyngeal, with cell bodies in geniculate ganglio
- terminate in nucleus tractus solitarius (gustatory/rostral area)

Question 9

What processes taste of epiglottis?

Answer 9

superior laryngeal nerve of vagus, with cell bodies in nodose ganglion
- terminate in nucleus tractus solitarius (gustatory/rostral area)

Question 10

What are the 3 components of the gustatory cortex?

Answer 10

1. postcentral gyrus
2. frontal operculum
3. insula