Olfaction and taste

Question 1

What is anosmias?

Answer 1

Selective olfactory deficits

Question 2

What determines the sensitivity of the olfactory system?

Answer 2

The number of olfactory receptor neurons

Question 3

What is the role of cilia in olfactory transduction?

Answer 3

Important for detection of the odorant. Carries olfactory receptors.

Question 4

Describe the signal transduction that occurs after binding of an oderant molecule to its receptor

Answer 4

G protein is activated which activates adenylate cyclase. This increases levels of cAMP which activates the Na/Ca channel. Influx of Ca activates a Ca gated Chloride channel causing chloride influx.

Question 5

If not through a G protein coupled receptor, how else can olfactory stimulation transduction work?

Answer 5

Through IP3 gated ion channels. This activates phospholipase C which opens calcium channels

Question 6

Receptor neurons expressing the same odorant receptor converge where?

Answer 6

In the same glomerulus of the olfactory bulb

Question 7

What are the three cell types of the taste bud?

Answer 7

taste cells, basal cells, and support cells

Question 8

Taste buds int he tongue are innervated by:

Answer 8

CN VII, CN IX, CN X

Question 9

Describe how the salt receptor works

Answer 9

Salt enters through an Na/H channel (amiloride sensitive Na channel), depolarization, calcium influx

Question 10

Describe how sour receptor works

Answer 10

H+ activated channel allows Na/Ca in. Depolarization, calcium influx, neurotransmitter release

Question 11

Describe how sweet/bitter receptors work

Answer 11

Sugar binds to TIR 2/3 receptors, (bitter only binds TR2)which are G protein coupled receptors. This activates Phospholipase C which synthesizes IP3 causing intracellular release of Calcium from the ER.

Question 12

How does umami flavor receptor work?

Answer 12

Glutamate from MSG binds to TIR1/3 receptor. Activates G protein, phospholipase C, synthesis of IP3, and intracellular calcium release from the ER ensues.

Question 13

Which hormones increase taste receptor cell sensitivity?

Answer 13

serotonin (5hT) and cholecystokinin

Question 14

Which hormones enhance olfactory cell response to salt?

Answer 14

aldosterone and vasopressin

Question 15

Where do taste neurons synapse on the cerebrum?

Answer 15

In the insula, near the motor cortex location for the tongue

Question 16

which disorders cause reduced olfactory abilities?

Answer 16

atrophic rhinitis and diabetes and alzheimers

Question 17

Which disorders cause reduced olfactory AND gustatory abilities?

Answer 17

chronic renal failure

Question 18

Which conditions result in enhanced olfactory and gustatory abilities?

Answer 18

cystic fibrosis and epilepsy

Question 19

What are the three systems with chemical senses?

Answer 19

Trigeminal, olfactory, and gustatory system

Question 20

What does the trigeminal system do?

Answer 20

Protective function that detects obnoxious and irritating compounds

Question 21

TRP channels

Answer 21

activated by changes in temperature. Also activated by compounds that are cool (menthol) or spicy (capsacin). Allows in Na and Ca causing depolarization

Question 22

The heat index of peppers correlates with the amount of:

Answer 22

caspacin

Question 23

Humans can detect odors down to what concentration?

Answer 23

10^-14

Question 24

What are the three types of olfactory receptor cells?

Answer 24

basal cells, supporting cells, receptor cells

Question 25

What adds to the sensitivity of the olfactory system?

Answer 25

Mitral cell. Convergence of many olfactory receptor neurons converging on one mitral cell

Question 26

Periglomerular cells

Answer 26

Forms synapses between glomeruli

Question 27

What are the olfactory bulb targets? Where does each end up?

Answer 27

pyriform cortex, olfactory tubercle, amygdala go to the thalamus, hypothalamus, and orbitofrontal cortex

Endorhinal cortex goes to hippocampal formation

Question 28

Emotional state can affect:

Answer 28

olfactory receptors

Question 29

Locus ceruleus (ex: Hunger) enhances sensitivity of:

Answer 29

olfactory bulb

Question 30

Orbitofrontal cortex is responsible for:

Answer 30

olfactory perception and identification

Question 31

hypothalamus’ role in olfactory information:

Answer 31

motivatonal or emotional response to scent

Question 32

What is the hippocampal role in olfactory information?

Answer 32

Olfactory memories

Question 33

Which papillae have taste buds?

Answer 33

fungiform papillae

Question 34

A taste bud has three cell types. WHat are they?

Answer 34

taste cells, basal cells, and support cells

Question 35

Taste receptor cells–are they primary receptor neurons?

Answer 35

No-Releases neurotransmitter onto another nerve

Question 36

Where is the gustatory cortex?

Answer 36

near the insula

Question 37

Taste receptors synapse where in the cortex?

Answer 37

In the insula, near the somatosensory cortex (homunculus)

Question 38

Describe the pathway of taste information

Answer 38

Cranial nerves 7,9,10 from tongue go to the solitary nucleus then to the:

1. amygdala
2. hypothalamus
3. VPM of thalamus to insula

Question 39

Which areas are responsible for visceral or emotional responses to taste?

Answer 39

hypothalamus and amygdala

Question 40

Which areas of the brain are responsible for identification of taste?

Answer 40

insula/frontal cortex