PHYS: Olfaction + Gustation

Question 1

Umami senses?

Answer 1

Glutamate

Question 2

Bitter senses?

Answer 2

Posions!

Coffee

Question 3

What happens when a taste cell gets activated?

Answer 3

It depolarizes

Question 4

Sour + salty trigger what?

Answer 4

A calcium-triggered release of seratonin

Question 5

Sweet, bitter, + umami (SUB) trigger what?

Answer 5

calcium-triggered release of ATP

Question 6

Answer 6

Question 7

Salty opens up _______ channel to secrete ______.

Answer 7

Salty = Epithelial Na+ Channel (ENaC)

releases 5-HT (seratonin)

Question 8

Sour is evoked by _____ and causes a ______ release.

Answer 8

Sour = evoked by H+ (acidic)

releases seratonin

Question 9

Sweet, Umami, and Bitter use what type of channel to increase Ca+ leading to depolarization and secretion of ATP?

Answer 9

GPCR

Question 10

What specific GPCR does umami use?

Answer 10

mGluR4

Question 11

Why do GPCRs have such high binding affinity?

Answer 11

bitter stuff is usually poison, so it binds with high affinity to save you from eating posionous stuff (evolutionarily helpful)

Question 12

What innervates taste buds?

Where do they terminate?

Answer 12

Special visceral afferent neurons

Terminate in the nucleus solitarius (gustatory area)

Question 13

We know that CN 7 innervates the ant. tongue, but what get the rest of it + the epiglottis?

Answer 13

Post. tongue = 9

Epiglottis = 10

Question 14

7 =

9=

10 =

Answer 14

7 = geniculate ganglia

9 = petrosal ganglia

10 = nodose ganglia

Question 15

What makes up the “gustatory cortex”?

Answer 15

Just the purple

Postcentral gyrus

Frontal operculum

Insula

Question 16

What is the pathway for ascending taste?

Answer 16

Nucleus tractus solitarius –> VPM –> post. limb of IC –> terminate in postcentral gyrus, frontal operculum, insular cortex

Question 17

What is responsible for hunger? (mechanism of eating)

Answer 17

Hypothalamus

Question 18

What is responsible for discrimitive aspects of taste?

Answer 18

VPM of thalamus

Question 19

What integrates visual, somatosensory, olfaction, and gustatory stimuli?

Answer 19

Gustaory cortex

Question 20

What is responsible for the emotional aspect of eating + memories of eating?

Answer 20

Amygdala

Question 21

What preforms the medullary reflex arcs that allow us to swallow + salivate?

Answer 21

Nucleus tractus solitarius

Question 22

What is the function of the Golf receptor? (listen to lecture)

Answer 22

On odorant stimulates it

Question 23

Golf stimulates –>

Answer 23

Adenylyl cyclase –> increases cAMP –> opens CNGC (cyclic nucleotide gated channels)

And if an odor persists then CGNC = desensitized or inactivated. It allows you to adapt or “get used to” a smell, so that you don’t notice it anymore.

Question 24

A high concentration of an odor smells like poop.

concentration matters

Question 25

What cells are found in the olfactory bulb?

Answer 25

Mitral cells, granule cells, periglomerular cells

Question 26

Which cells release GABA?

Answer 26

Granular + Perislomerular (interneurons)

Question 27

What do olfactory neurons release?

Answer 27

Glutamate

Question 28

What is the only sensory system that does not route through the thalamus before connecting to the cortex?

Answer 28

Olfactory (smell)

Question 29

Question 30

What is the function of the anterior olfactory nucleus?

Answer 30

Relay station to the cortices

Question 31

The piriform cortex ---\> lateral hypothalamus functions in?

Answer 31

Control of appetite/hunger

Question 32

Piriform cortex --\> thalamus --\> medial orbitofrontal cortex functions to?

Answer 32

Integrate taste, sight, and smell Appriciate food

Question 33

The anterior cortical amygdaloid nucleus functions in?

Answer 33

emotional learning olfactory fear conditioning

Question 34

The periamygdaloid cortex functions in?

Answer 34

Emotional aspect of an odor | (like when I smell dead bird)

Question 35

Lateral entorhinal cortex ---\> hippocampus

Answer 35

Important in memory formation + recall

Question 36

Are taste receptors neurons?

Answer 36

no they are modified epithelia cells w/: 1. Fixed permeability (stay open @ rest) 2. Shifting Na+ gradient

Question 37

How do you describe olfactory receptors?

Answer 37

They are neurons: 1. Fixed Na+ gradient 2. Shifting permeability

Question 38

To get "flavor" what 3 things do you need input from?

Answer 38

1. Gustatory cortex 2. Olfactory cortex 3. Somatosensory from mouth MEDIAL ORBITOFRONTAL CORTEX

Question 39

When you get a cold and thickened mucus blocks odorants from binding, what is this called?

Answer 39

Reversible hyposmia

Question 40

Why is smell strongly correlated w/ memory?

Answer 40

Because, the hippocampus + amygdala = limbic system ---\> mood + emotions They associate an emotional response w/ odors. Thats why if you had a traumatic experience and smell something like it it will bring you back. They also allow for memories after the odor stops.