Physiology Of Taste

Question 1

What is the pathway of taste?

Answer 1

As through the thalamus before they project to their relevant cortical area

Taste afferents from the midbrain are involved in visceral reflexes (e.g. secretion of gastric juices)

Question 2

What 2 sensations?

Answer 2

Chemosensory and somatosensory

Question 3

What are the 5 taste sensations?

Answer 3

Umami
Sweet
Sour
Bitter
Salty

Question 4

How are sourness and saltiness detected?

Answer 4

Sodium ions and hydrogen ions across a membrane

Question 5

What does transduction of wetness and bitterness involve?

Answer 5

2nd messengers

Question 6

What is umami associated with?

Answer 6

Glutamate

Question 7

Where are the receptors for umami taste?

Answer 7

Back of the pharynx

Question 8

What nerves are involved in taste?

Answer 8

Primary sensory jnpit to the cortex travels via the

facial (frontal of tongue),

Glossopharyngeal (back of tongue) and

vagus (soft palate and mouth)

Question 9

Where does the taste/food go?

Answer 9

Taste pore

Question 10

Wheat happens when the taste sensory cells are depolarised?

Answer 10

Transmit AP and taste sensed

Question 11

What are papillae in order?

Answer 11

Circumvallate

Folliate

Fungiform

Question 12

How is taste sensed? (Pathway)

Answer 12

Action potentials to the gustatory cortex

Question 13

What papillae is shown?

Answer 13

Circumvallate

Question 14

What receptor senses sweet?

Answer 14

T1R family

Question 15

What receptor senses bitterness?

Answer 15

T2R family

Question 16

What receptor senses glutamate?

Answer 16

t-mGluR4

Question 17

What receptor senses sodium salt?

Answer 17

Question 18

What receptors are 7 pass transmembrane receptors?

Answer 18

Question 19

Why is there variability in taste between individuals?

Answer 19

There are variable amino acids between membrane of R families

Question 20

What is the taster mouse?

Answer 20

Amino acids exchanged so the mouse cannot taste sweet taste

Question 21

How can a sweet receptor bind to different sweet ligands?

Answer 21

Dimerisation of receptors

Question 22

What does depolarisation cause?

Answer 22

Increase Ca2+ into the cell and NTrelease

Question 23

What type of receptor do. Utter and sweet ligands use?

Answer 23

GPCR in membranes

Question 24

Describe the pathway of sweet ligands on GPCR

Answer 24

Sweet ligands, gustducin, activates a cAMP second messenger that closes K+ channels and depolarise the cell

And increase Ca2+ and neurotransmission

Question 25

What happens when the bitter ligand binds the GPCR?

Answer 25

The butter ligand, transducin, releases Ca2+ from intracellular

Release of Ca2+ from intracellular stores and NT

Question 26

What type of channel do sour and salt trigger?

Answer 26

Ion channels and depolarise the cell, trigger extracellular Ca2+ entry