Olfaction and Taste

Question 1

How long is turnover of olfactory receptor cells?

Answer 1

60 days

Question 2

What is the target of cAMP in olfactory receptor cells?

Answer 2

CNG channel

Question 3

What does Ca2+ do in the olfactory receptor cell?

Answer 3

Opens a chloride channel so chloride can flow out and cause a depolarising current

Question 4

What is the secondary function of Ca2+ in the olfactory receptor cell?

Answer 4

Acts via calmodulin to suppress CNG channel sensitivity and contribute to adaptation?

Question 5

How is the Ca2+ extruded from the olfactory receptor cell?

Answer 5

Na-Ca-K exchange

Question 6

What do olfactory cells synapse with?

Answer 6

Mitral and tufted cells

Question 7

How do periglomerular cells inhibit neighbouring mitral cells?

Answer 7

Lateral interactions using reciprocal dendrodendritic synapses

Question 8

Where does medial dorsal nucleus of thalamus project to?

Answer 8

Orbitofrontal cortex

Question 9

Where does olfactory tubercle project to?

Answer 9

Thalamus

Question 10

Where does amygdaloid complex project to?

Answer 10

Hypothalamus and reticular formation

Question 11

Where does entorhinal cortex project to?

Answer 11

Hiipocampus

Question 12

Where does pyriform cortex project to?

Answer 12

Other olfactory cortical regions

Question 13

In what brain region is there more olfactory sensitivty (doesn’t respond to lots of odours)?

Answer 13

Pyriform, amygdala and orbitofrontal

Question 14

Where does vomeronasal organ send signals to?

Answer 14

Accessory olfactory bulb then amygdala

Question 15

What connects apical tips of cells in taste buds?

Answer 15

Tight junctions

Question 16

What are the classical taste qualities?

Answer 16

Bitter, sweet, sour and salt

Question 17

What do presynaptic cells detect?

Answer 17

Acid

Question 18

What do receptor cells detect?

Answer 18

Bitter, sweet and umami

Question 19

What do glial-like cells do?

Answer 19

Potassium and transmitter homeostasis

Question 20

What are the umami receptors?

Answer 20

T1R1 and T1R3

Question 21

What are the sweet receptors?

Answer 21

T1R2 and T1R3

Question 22

What does calcium do in the taste receptor?

Answer 22

Opens TrpM5 letting Na in and Panx1 letting ATP out

Question 23

What does ATP do in the taste receptor?

Answer 23

Acts as local purinergic transmitter via gap junction hemichannels

Question 24

How does Na depolarise the cell?

Answer 24

Flows in through ENaC channels

Question 25

Where do taste afferents go in the human?

Answer 25

Nucleus solitarius within gustatory nucleus, then VPMN of thalamus, then the gustatory neocortex in the anterior insula and frontal operculum

Question 26

Where do taste afferents go from the primary taste cortex?

Answer 26

To secondary taste area in the orbitofrontal cortex and the amygdala

Question 27

What is an across fibre code?

Answer 27

Taste identified by patterns of activity in different fibres

Question 28

What do afferent taste fibres receive input from?

Answer 28

ATP but also presynaptic cells via serotonin release which themselves require purinergic inout

Question 29

Which CNs carry taste?

Answer 29

VII, IX, X

Question 30

Is taste contralateral or ipsilateral?

Answer 30

Ipsilateral

Question 31

Where do taste fibres go?

Answer 31

CNs go to medulla, then to VPMN of thalamus, the to gustatory cortex, then either to lateral hypothalamus, amygdala or orbitofrontal

Question 32

What is the receptor molcule which odorant binds to?

Answer 32

Golf

Question 33

What do granule cells that are strongly excited inhibit?

Answer 33

Weakly responding mitral cells

Question 34

Which papillae have embedded taste buds?

Answer 34

Fungiform, foliate and circumvallate