Olfactory/Gustatory Physio

Question 1

5 categories of tastants

Answer 1

• Sour
• Salty
• Sweet
• Bitter
• Umami

Question 2

Umami is associated with…

Answer 2

Glutamate

Question 3

Bitter is associated with…

Answer 3

Poisons/Coffee

Question 4

Tastants associated with Ca2+ triggered release of serotonin

Answer 4

Salty and Sour

Question 5

Tastants associated with Ca2+ triggered release of ATP

Answer 5

Sweet, Umami, Bitter (SUB)

Question 6

What receptor is crucial in the release of ATP?

Answer 6

TRPM 5

Question 7

What 3 cortical areas make up the gustatory cortex?

Answer 7

• Postcentral gyrus
• Frontal operculum
• Insula

Question 8

Which parts of the pathway are responsible for the discriminative aspects of taste?

Answer 8

VPM and Gustatory cortex

Question 9

Which parts of the pathway integrate visual, somatosensory, olfaction and gustatory stimuli?

Answer 9

Orbitofrontal cortex

Question 10

Role of nucleus tractus solitarius

Answer 10

Receives afferents from CN VII, IX and X for taste, as well as other visceral info from CN X.

It also regulates medullary reflex arcs (swallowing, salivating, etc.)

Question 11

What type of cells are olfactory cells?

Answer 11

Bipolar cells (very adaptable)

Question 12

What type of receptors are olfactory receptors?

Answer 12

GPCRs

Question 13

Describe how the olfactory system adapts to smells

Answer 13

As odorant stimulation persists, sensitivity of CNGC to cAMP decreases, thus reducing cation influx.

Can also be inactivated by receptor phosphorylation

Question 14

How do odor receptors detect more smells than there are receptors?

Answer 14

• Combos of different stimuli act like signatures

- Concentration of odorant affects perception of smell

Question 15

Purpose of granular cells?

Answer 15

• Local interneurons that release GABA to increase specificity of signal

Question 16

Purpose of periglomerular cells?

Answer 16

• Local interneurons that release GABA to increase specificity of signal

Question 17

What do mitral and tufted cells do?

Answer 17

Project back to the olfactory tract

Question 18

Where do olfactory neurons synapse and what do they do?

Answer 18

• Synapse onto glomeruli

- Release Glutamate

Question 19

What does the olfactory cortex consist of?

Answer 19

• Anterior olfactory nucleus
• Olfactory tubercle
• Piriform cortex
• Ant. cortical amygdaloid nuclei
• Periamygdaloid cortex
• Lateral entorhinal cortex

Question 20

Where does the olfactory cortex project to?

Answer 20

• Intrinsic projections w/in cortex
• Back to olfactory bulb
• Thalamus
• Orbitofrontal cortex
• Lateral hypothalamus
• Hippocampus

Question 21

Role of anterior olfactory nucleus

Answer 21

Relay station to IL and CL cortices

Question 22

Where does anterior olfactory nucleus travel to?

Answer 22

• CL olfactory bulb/olfactory cortex
• IL olfactory bulb
• Lateral hypothalamus
• Dorsomedial thalamic nucleus
• Insula/orbital cortex

Question 23

Piriform Cortex —

Answer 23

Lateral hypothalamus

- Controls appetite

Question 24

Piriform Cortex — … —

Answer 24

Piriform cortex - thalamus - medial orbitofrontal cortex

• Integration of taste, sight, smell
• Appreciation of flavor of food

Question 25

Anterior cortical amygdaloid nucleus

Answer 25

Emotional learning and olfactory fear conditioning

Question 26

Periamygdaloid cortex

Answer 26

Integration of emotional aspect elicited by odor

Question 27

Etorhinal cortex ---

Answer 27

Hippocampus | - Memory formation

Question 28

Biggest difference b/w taste receptors and olfactory receptors?

Answer 28

- Olfactory receptors are neurons with fixed Na+ gradient and shifting permeability - Taste receptors are epithelial cells with shifting Na+ gradient and fixed permeability

Question 29

What is required for perception of flavor?

Answer 29

- Gustatory input from gustatory cortex - Olfactory input from olfactory cortex - Somatosensory info from mouth * All w/in medial orbitofrontal cortex

Question 30

Where does adult neurogenesis occur?

Answer 30

Olfactory bulb and dentate gyrus of hippocampus

Question 31

Main cause of reversible hyposmia?

Answer 31

Thickened mucus in nose d/t cold (this blocks odorants from entering)

Question 32

How/why does olfaction strongly influence memory?

Answer 32

- Interconnectedness of temporal lobe w/ amygdala and hippocampus