Block 2 Exam: Taste and Olfaction

Question 1

4 properties of stimulus

Answer 1

1. Modality- which sensory neurons are activated
2. Location-sensory regions organized according to incoming signals. Adjacent sensory input is processed in adjacent columns.
3. Duration- encoded by duration of AP
4. Intensity- encoded by # of AP (or fibers activated)

Question 2

Labelled Line

Answer 2

coding model in which peripheral neurons that respond the most robustly to a given sensory modality carry the information via segregated pathways (wire from periphery to cortex).

Question 3

Ensemble Code

Answer 3

stimulus and intensity are encoded by ensembles of broadly-tuned neurons.

Question 4

Sweet triggered by

Answer 4

Sugars T1R2/T1R3

Question 5

Bitter triggered by

Answer 5

organic ions; TAS2R/T2R5

Question 6

Umami triggered by

Answer 6

organic ions; T1R1/T1R3

Question 7

Sour trigged by

Answer 7

H+ ions(pH); Pkd211-DTA

Question 8

Salty trigged by

Answer 8

Na+ ions;

Question 9

Oleogustus trigged by

Answer 9

fatty acids; GPR40/GPR120?

Question 10

ATP is NT for

Answer 10

Sweet, Umami, Bitter

Question 11

Serotonin is NT for

Answer 11

Salty and Sour

Question 12

Each papillae has ____ taste buds. Taste buds have _____ receptor cells.

Answer 12

Papillae has 1-100 taste buds.

Taste bud have 50-150 receptor cells

Question 13

Taste: binding of substrate either

Answer 13

1. Depolarizes taste receptor allowing for Ca2+ influx

2. Causes release of Ca2+ from intracellular stores.

Question 14

General Bitter Sweet Umami pathway

Answer 14

Alpha-gustduclin –>
PL-Beta-2 – >
IP3 –> Ca2+ –> Na+ influx –> NT Release on afferent axons.

Question 15

Taste Pathway:

Anterior tongue/Posterior tongue/Epiglottis —> ________ –> _____ (thalamus) —> ______

Answer 15

Tongue –> Gustatory nucleus –> VPN thalamus –> Gustatory cortex

Question 16

Where is primary gustatory cortex located?

Answer 16

above lateral fissure, within insular cortex

Question 17

What cranial nerves (taste) go medulla –> gustatory nerves of solitary tract -> VPM of thalamus

Answer 17

Cranial Nerves 7, 9, 10

Question 18

Papillae- carry ___ ___, which have various taste cells, which release NT on gustatory afferent axons.

Answer 18

Taste buds.

Question 19

What causes NT release in afferent axon?

Answer 19

brainstem Ca2+ signal

Question 20

Taste:
Primary afferents axons go to ____.
Secondary afferent axons send info to ____.

Answer 20

Brainstem

Thalamus –> gustatory cortex (insular cortex, in the lateral fissure)

Question 21

Cranial Nerve 7

Answer 21

anterior tongue; salty/sour

Question 22

Cranial Nerve 9

Answer 22

back of the tongue; bitter/acid

Question 23

Cranial Nerve 10

Answer 23

epiglottis and throat area; acid (acid more back of throat)

Question 24

Evidence for ensemble coding in taste cells

Answer 24

cranial nerves carry various taste sensations

Question 25

Cranial Nerve 7 goes to…

Answer 25

CT: Branch of facial nerve (mostly salty/acid)
GSP: branch of facial nerve
(mostly acid/bitter)

Question 26

Cranial Nerve 9 goes to…

Answer 26

GP: glossopharyngeal nerve (mostly sweet/acid)

Question 27

Cranial Nerve 10 goes to…

Answer 27

SLN- branch of vagus

mostly acid/water

Question 28

Taste evidence for labelled line coding…

Answer 28

The basic tastes are represented in spatial map in the primary taste cortex.

Specific areas of cortex light up in response to a taste. Hot sports for individual tastes. However, there is some overlap.

Question 29

We inhale air which goes through ____ ____. Odorants dissolve in ____, which activates receptors in cilia to cause depolarization.

Answer 29

Olfactory epithelium

Mucus

Question 30

Name 3 cells in olfactory epithelium

Answer 30

1. Olfactory receptor neurons
2. Supporting Cells
3. Basal Cells

Question 31

Olfactory receptor cells

Answer 31

bipolar, continuously regenerate

Question 32

Supporting cells

Answer 32

similar to glia, produce mucus with Bowmann glands

Question 33

Basal Cells

Answer 33

Source of new receptor cells (stem cells)

Question 34

Olfaction: (In cilia)

Odorant –> ____ (protein type) –> Adenylyl cyclase–> ____ –> influx of _____ –> Cl- out of cell.

Answer 34

Golf- –> Adenylyl cyclase –> cAMP –> influx of Ca2+/Na+ –> Cl- out of cell

Question 35

Name the 5 ways that olfactory response can terminate.

Answer 35

1. Odorant diffuses away
2. Enzymes in mucus break them down
3. Termination of signaling
4. Adaptation
5. Masking

Question 36

Generally receptor respond to many odorants but

Answer 36

show preference

Question 37

Olfaction: 25,000 primary neurons synapse onto

Answer 37

100 second order mitral/tufted cells (convergence)

Question 38

The olfactory bulb divides the media and lateral ___. The lateral generally goes to the ___ area.

Answer 38

Stria

Puriform.

Question 39

Olfaction: go to areas like olfactory tubrical, amygdala, and puriform, and innerrinel cortex which are involved in

Answer 39

memory

Question 40

Primary olfactory neurons go to ____ cells in olfactory tract.

Answer 40

mitral

Question 41

Where go axons from medial stria go?

Answer 41

Septal nulcei
OR
inhibit mitral cell activity in contralateral bulb

Question 42

The idea that different odorants can activate unique but overlapping neurons in pyriform cortex is

Answer 42

Cortical processing of odors.

Question 43

Ensembling coding in olfaction

Answer 43

Cells that respond to different odorants are diffusely distributed in pyriform cortex (no spatial organization)