Sense of taste (gustation) Flashcards
What comes first in gustation?
Food chemicals must be dissolved
Papillae
Projections made up of many taste buds
Taste buds contain taste cells called
Tastants
Tastant cells do what two things
- Identify concentrations + quality of food
- Prep GI tract
Taste cells are specialized for
Sensory transduction
Basal cells are used for
taste stem cells- replaced every 10 days
Taste cells contain
Vesicles filled with NTs
The taste system detects 5 perceptually distinct categories of tastants. What are they?
- Salt
- Sour
- Sweet
- Bitter
- Umami
Salt
metallic ions;NaCl
Sour
H+; acidity
Sweet
Sugar/Glucose
Bitter
Alkaloid
Umami
Savory/Meaty (Glutamate)
Is taste segregated in different places on the tongue?
NO; Each taste bud contains taste cells that have receptors for multiple flavors
Many bitter compounds are ________________
Poisonous
The possibility of poisonous bitter compounds have a
Lower threshold than others
T1 receptors bind ______; ionotropic or metabotropic
Things like glutamate; metabotropic
T2 receptors bind ____________; ionotropic or metabotropic
Glucose/sugars; metabotropic
T2 Membrane receptors bind _______; ionotropic or metabotropic
Bitter solutions; metabotropic
ENaC membrane receptors bind ________; ionotropic or metabotropic
Sodium; ionotropic
PkD2L cell receptors bind ___________; ionotropic or metabotropic
Sour; ionotropic
When receptors are depolarized.
they release NTs
G-proteins in T1 and T2 activate
an increase in concentration of IP3
IP3 in cells increases
intracellular Ca2+
An increase in intracellular Ca2+ _______________
Opens the TRP Ca2+ channel, depolarizing the cell
What are the 3 major receptor nerves that innervate the tongue?
1.Facial nerve CN7
2. Glossopharyngeal CN9
3. Vagus CN10
Facial nerve is in charge of what quadrant of the tongue
Front 2/3
Glossopharyngeal nerve is in charge of what quadrant of the tongue
Back 1/3
Vagus nerve is in charge of what quadrant of the tongue
Esophagus
These three nerves synapse onto Specific parts in what part of the brain
Solitary nucleus in Medulla Oblaganta
From the solitary nucleus, taste info transfers to the
Ventral Posteromedial nucleus (VPM)
From the VPM, info goes into the
Gustatory cortex
Where is the gustatory cortex located
Insula in temporal lobe