Gustatory System

Question 1

5 Basic Tastes

Answer 1

Salty, Sour, Sweet, Bitter, Umami (savoury)

Question 2

Salty

Answer 2

Relates to: Vital electrolytes
Human Preference: High Salt content
Relevance: Required for many physiological processes

Question 3

Sour

Answer 3

Relates to: Acidity (H+ ions)
Human Preference: Avoid high acidity
Relevance: avoid rotting food as many rotten foods are acidy which an cause injury to GI tract

Question 4

Sweet

Answer 4

Relates to: Sugars
Human Preference: High Sugar content
Relevance: Required for energy and growth
* Flavour we first learn to enjoy as a child i.e in breast milk

Question 5

Bitter

Answer 5

Relates to: Diverse chemical structures make bitter taste
Human Preference: Avoid bitter content
Relevance: Avoid toxic substance and poisonous ones

Question 6

Umami

Answer 6

Relates to: AA e.g Glutamate
Human Preference: High AA preference
Relevance: Protein synthesis, neurotransmission

Question 7

How do we differentiate food apart from taste

Answer 7

Texture, Temp + Balance (ratio of tastes) help us differentiate foods

Question 8

Tongue

Answer 8

2000 - 5000 taste buds

100 chemoreceptive taste cells per taste bud

Question 9

Lingual Papillae

Answer 9

Contain taste buds which are groups of taste cells

They are dotty structures in the tongue

Question 10

Papillae types

Answer 10

Filiform papillae - detect texture in the middle of tongue
Fungiform papillae - Evaginations (protrusion) with taste buds on top
Circumvallate papillae - at the back of tongue where majority of taste cells are found.

Question 11

Taste pore

Answer 11

Sensory transduction occurs at the top of taste pores between pore microvilli and saliva.
Synaptic transmission happens at base of taste buds with gustatory afferent nerve

Question 12

Tastes that use ion channels

Answer 12

Salty - involves ENAC (Epithelial NA+ channels) + unknown mechanism. KO ENAC still detect salt = ENAC not only detection
Sour - OTOP1 which is the sour perceiving channel

Question 13

Tastes that use G-Protein coupled receptors

Answer 13

Bitter - Bitter tastes activates T2R’s
Sweet - activates T1R2 + T1R3
Umami - activates T1R1 + T1R3
These bind to EC domain on G-Protein receptors triggering a cascade in the cells

Question 14

How many stimuli do taste cells respond to?

Answer 14

Taste cells only respond to 1 type of stimuli

But taste buds contain taste cells which respond to various stimuli