Olfaction & Taste

Question 1

Olfactory Chemoreceptor

Answer 1

• located in olfactory epithelium in upper part of nasal cavity
• chemical stimuli bind to these to cause a signal ( specific chemoreceptors for certain stimuli)

Question 2

Olfactory Bulb

Answer 2

• bundle of nerves that send projections through cibriform plate into the olfactory epithelium
• contain thousands of different epithelial cells with different chemoreceptors that are activated by specific stimuli which then triggers a g-protein activation and cascade of events inside the cell

Question 3

What is the pathway of olfaction? (from nostril to brain)

Answer 3

1. nostril
2. nasal cavity
3. olfactory chemoreceptors
4. olfactory bulb
5. olfactory tract
6. higher order brain regions like the limbic system

Question 4

Pheromones

Answer 4

• specialized olfactory cells bind these chemical signals released by one member of species and sensed by other member of species to trigger an innate response
• plays roles in social, forging, and sexual behavior

Question 5

Humans have ______ organ but do not have accessory _____ ____ that is directly involved with amygdala

Answer 5

• vomeronasal

- olfactory bulb

Question 6

What are the 5 main tastes?

Answer 6

• bitter
• sour
• sweet
• salty
• umami

Question 7

How many receptor cells are in each taste bud?

Answer 7

5 receptor cells in each taste bud that detect each type of taste

Question 8

Where are the majority of tastebuds located on the tongue?

Answer 8

anterior side of tongue

Question 9

What are the Labelled Lines found on the Gustatory Cortex?

Answer 9

created by each receptor cell’s axon (that remain separate from other axons in the brain) synapsing on same part of gustatory cortex as receptor cells of the same taste

Question 10

Which tastes have GPCR receptors?

Answer 10

• sweet
• umami
• bitter

Question 11

Explain the pathway of GPCR receptors

Answer 11

stimuli bind to GPCR -> conformational change in receptor -> G protein dissociates -> ion channel opens -> cell polarizes -> cell fires AP

Question 12

Which tastes rely on ion channels?

Answer 12

• sour

- salty

Question 13

How does ion channel activation occur?

Answer 13

stimuli directly binds to receptor -> ion channel opens -> cell depolarizes -> cell fires AP

Question 14

Describe the taste pathway (taste buds to brain)

Answer 14

taste information travels from taste buds (found on papillae) to brainstem and then ascends to taste center in thalamus then to higher order brain regions