Smell and Taste (Karius)

Question 1

what receptors have a high turnover rate, odorant or taste and what can effect them

Answer 1

both, chemotherapy

Question 2

what is added to natural gas to alert us to the presence of it and what happens with age

Answer 2

mercaptan, sensiativty to this smell declines with age

Question 3

what kind of receptors are odorant receptors

Answer 3

G-protein coupled that create cAMP to open cyclic nucleotide gated ion channel
-Gs or Golf

Question 4

what happens if odorant persists for more than a few minutes

Answer 4

the sensitivity of the channel to cAMP is reduced decreasing Na+ and Ca++ entry
-AP potential is reduced

Question 5

what happens when odorant concentration is really high

Answer 5

changes perceived smell because it starts to bind other receptors that have a low affinity for that odorant

Question 6

what is TAARs receptors

Answer 6

activation does not necessarily lead to conscious awarenes of an order, instead produce physiologic/endorcine responses to pheromones

Question 7

transmission to the brain of smell, neurons involved

Answer 7

axons of olfactory neurons pass through cribfriform plate and synapse on neurons of the olfactory bulb

Question 8

layers of the olfactory bulb

Answer 8

granule cell layer
mitral cell layer
external plexiform layer
glomerular layer
olfactory nerve layer

cribriform plate
olfactory epithelium

Question 9

which cels of the olfactory bulb are not directly activated by olfactory cells

Answer 9

the granule cells

Question 10

the olfactory neruons will synapse with what cells in the glomeruli

Answer 10

mitral cells
tufted cells
periglomerular cells

Question 11

which cells of the glomeruli have axons going to the cortex and which have cell axons that stay in the olfactory bulb?

Answer 11

mitral cells and tufted cells have axons go to cortex (axons join olfactory tract)
periglomerular cell axons will remain in the olfactory bulb

Question 12

role of periglomerular cells

Answer 12

release GABA at their synaptic contact with other glomeruli and inhibit the activity from those glomeruli

Question 13

function of the granular cells

Answer 13

also release GABA at their synaptic contacts but they synapse with mitral and tufted cells
-also increase specifictiy of message going to olfactory cortex

Question 14

first possible synapse in olfactory cortex

Answer 14

in anterior olfactory nucleus

-synapses relay info to contralateral side and axons also continue on the ipsilateral side

Question 15

what are the 2 main parts of the olfactory cortex most important in smell perception

Answer 15

piriform cortex

lateral entorhinal cortex

Question 16

where does the entorhinal cortex project and what is its function

Answer 16

hipposcampus and memory function

Question 17

where does the piriform cortex project to and what is the function

Answer 17

lateral hypothalamus and control of appetite

also to medial orbitofrontal cortex via the thalamus to provide information that is used to identify the flavor of foods

Question 18

where does the olfactory cortex send input back to

Answer 18

the olfactory bulb/epithelium to modify receptor responses to odorants

Question 19

when is sour taste produced

Answer 19

when hydrogen ion enters the taste bud via a hydrogen-ion channel

Question 20

how is salty taste produced

Answer 20

when sodium or calcium ion enter the taste bud via a sodium or calcium channel

Question 21

what kind of receptor is the umami taste receptor

Answer 21

metabotropic glutamate recepter activated by glutamate

Question 22

gustary input synapses

Answer 22

NTS
thalamus
gustatory cortex (includes anterior insular cortex)

Question 23

synapse for gustary at thalamus goes where next

Answer 23

cortex and the lateral hypothalamus

-input has significant impact on appetite

Question 24

what does the perception of flavor require

Answer 24

gustatory input from the gustatory cortex
olfactory input from olfactory cortex (especially piriform cortex)
somatosensory info from the mouth

Question 25

where do neurons for all three areas of cortex for taste send axons to and this produces what

Answer 25

lateral posterior orbitofrontal cortex to produce sensation of flavor and appreciation of food