DSA: Olfactory and Taste

Question 1

describe the signaling of olfactory receptors.

Answer 1

Golf to ATP via AC= cAMP; connected to GNC channels allowing Na+ and Ca2+ to flow into neuron

Question 2

Describe what happens when an odorant persists.

Answer 2

decrease sensitivity of the channel to the cAMP; decreasing Na+ and Ca2+ entry, therefore a smaller generated potential results, reducing the probability of an action potential

Question 3

olfactory neruons express ________ odorants receptor on ALL of its cilia.

Answer 3

same

Question 4

Describe placement of specific odorant receptors.

Answer 4

receptors are localized to areas of the olfactory epithelium, however, the receptors are concentrated in specific areas and all olfactory epithelium has odorant receptors

Question 5

What is the significance of the placement of odorant receptors?

Answer 5

allows for odorants to have a better chance at binding to a receptor
ex: you have a cold, the mucosa block covers the olfactory epithelium, have odorant receptor all over, still are able to smell enough if the smell is altered

Question 6

odorants activate ________ odorant receptors?

Answer 6

multiple

different combs. of receptors activated produces a variety of smells and gives characteristic odor

Question 7

Describe how concentration of odorant determines smell.

Answer 7

at low concentration only receptors with high affinity for the odorant bind producing a specific smell
as concentration increases different odorant receptors bind the odorant thus altering the smell

at very high concentration smell may become putrid and nauseating

Question 8

What receptor is responsible for binding pheromones?

Answer 8

TAAR (trace amine-associate receptots)

Question 9

What are the 3 post-synaptic neurons transmitted olfactory info. to the brain?

Answer 9

mitral
tufted
periglomerular

Question 10

Describe the pathway of olfactory info to the brain.

Answer 10

olfactory neuron, through holes in the cribriform plate, to olfactory bulb, glomeruli, axon terminals from olfactory neurons synapse and release EAA on the dendritic tress of the post-synaptic neurons

Question 11

Periglomerular release ____ to inhibit glomeri

Answer 11

GABA

this increasing ability to discriminate smells; sends the strongest stimulus to the brain

Question 12

What is the olfactory Cortex composed of?

Answer 12

1st synapse= anterior olfactory nucleus ( which relays info to contralateral and ipsilateral hemispheres

anterior olfactory nucleus
piriform cortex
anterior cortical amygdaloid nucleus 
periamygdaloid  cortex
lateral entorhinal cortex

Question 13

Where does the entorhinal cortex project its signals?

Answer 13

hippocampus, which is important in memory formation

Question 14

What two placed does the piriform cortex project and what is the significance?

Answer 14

Lateral hypothalamus
controls appetite, why smells can influence hunger
Back to olfactory bulb
modify the receptor responses to odorants

Question 15

What are the 5 taste receptors?

Answer 15

sweet
salt
sour
bitter
Umami

Question 16

Does does the receptor response to “salt”?

Answer 16

the response is to the Na+, Ca2+ via a Na+ channel

Question 17

Does does the receptor response to “sour”?

Answer 17

the response is to H+ ions; hydrogen-channel allow H+ to flow into the cell, then block Na+ channels

Question 18

Does does the receptor response to “umami”?

Answer 18

metabotropic glutamate receptor

Question 19

Does does the receptor response to “sweet” and “bitter”?

Answer 19

2nd messengers systems

Question 20

Taste info. synapse in what 3 places of the brain?

Answer 20

NTS (nucleus tractus solitary)
Thalamus
Gustatory Cortex

Question 21

What is the consequence of info. synapsing in the thalamus?

Answer 21

sends info. to cortex and lateral hypothalamus; thus has an impact of appetite

Question 22

What is the consequence of info. synapsing in the Gustatory Cortex?

Answer 22

responsible for basic taste

attraction to sweet tastes or aversion to bitter taste

Question 23

How do we perceive flavor?

Answer 23

3 things:

1. Gustatory input
2. Olfactory input
3. Somatosensory info from the mouth

together sense axons to the lateral posterior orbitofrontal cortex to produce the sensation of flavor and appreciation of food.