Physiology of Taste & Smell

Question 1

Taste receptor cells are comprised _________ of that synapse on _____

Answer 1

modified epithelial cells ; neurons

Question 2

olfactory receptor cells are

Answer 2

neurons

Question 3

The receptors for taste are primarily located in the taste buds, which contains both _______ and ___________ cells

Answer 3

sensory (receptor) ; supportive

Question 4

The receptor cells found in the taste buds contain microvilli on their ______ ends

Answer 4

apical

Question 5

taste buds have a lifespan of about

Answer 5

10 days

Question 6

microvilli project into an opening called the

Answer 6

taste pore

Question 7

Gustants that are dissolved in saliva can bind to these receptors and initiate

Answer 7

downstream effects

Question 8

The binding of the gustant stimulates a ________ which ______ voltage-gated calcium channels

Answer 8

depolarization ; opens

Question 9

The binding of the gustant stimulates a depolarization whichs open voltage-gated calcium channels - this stimulates the release of a ________, triggering _________ in afferent neurons to the brain

Answer 9

transmitter ; action potentials

Question 10

cravings for non-food items like detergents, clay, soil (called Pica) is associated with

Answer 10

iron-deficiency anemia

Question 11

the salt receptor is a

Answer 11

sodium channel

Question 12

The microvilli of sensory taste cells contain a receptor for sodium that also acts as a

Answer 12

channel

Question 13

The sodium receptor that acts as a sodium channel is called the ________

Answer 13

epithelial sodium channel (ENaC)

Question 14

The movement of sodium down its electrochemical gradient into the taste receptor cell causes a

Answer 14

depolarization

Question 15

The movement of sodium down its electrochemical gradient into the taste receptor cell causes a depolarization which leads to ___________ and the __________

Answer 15

downstream effects and the release of a transmitter

Question 16

sour foods contain high levels of

Answer 16

hydrogen ions (H+)

Question 17

There are multiple ways in which hydrogen ions can be detected by the taste cells:

Hydrogen ions can enter the cell through the _______ utilized for salt recognition

Answer 17

ENaC channel

Question 18

There are multiple ways in which hydrogen ions can be detected by the taste cells:

Hydrogen ions can also bind to and activate channels that facilitate _____ INFLUX

Answer 18

Na+

Question 19

There are multiple ways in which hydrogen ions can be detected by the taste cells:

Hydrogen ions can bind to channels and block ____ EFFLUX

Answer 19

K+

Question 20

The multiple ways H+ ions can be detected by the taste cells are most likely initiated SIMULTANEOUSLY, with the end effect of cell ________ and
__________

Answer 20

depolarization ; transmitter release

Question 21

Umami receptors are activated by _________, such as glutamine, which are important components of muscles, organs, transport proteins, etc

Answer 21

amino acids

Question 22

The umami receptors are stimulated by

Answer 22

monosodium glutamate (MSG)

Question 23

Despite the great variance in these 3 taste sensations, the signaling mechanisms are the same for ______, _____ , and ______ modalities

Answer 23

bitter
sweet
umami

Question 24

For bitter/sweet/umami:

The gustant binds to a _________ and _______ the G-protein

Answer 24

G-protein coupled receptor ; activates

Question 25

For bitter/sweet/umami: The alpha subunit of the G-protein activates the enzyme _______

Answer 25

phospholipase C

Question 26

For bitter/sweet/umami: The alpha subunit of the G-protein activates the enzyme phospholipase C, which cleaves PIP2 into ____ and _____

Answer 26

DAG and IP3

Question 27

For bitter/sweet/umami: IP3 _______ intracellular calcium levels, leading to the ______ of a non-specific cation channel

Answer 27

increases ; opening

Question 28

For bitter/sweet/umami: The influx of cations such as sodium _______ the taste receptor cell, leading to

Answer 28

depolarizes ; transmitter release

Question 29

which is the better developed sense in humans: olfaction or taste?

Answer 29

olfaction

Question 30

olfactory receptor cells have a lifespan of

Answer 30

4-8 weeks

Question 31

Olfactory cells have small ______ at one end that detect _________

Answer 31

dendrites ; chemical stimuli

Question 32

After dendrites on olfactory cells detect chemical stimuli, AXONS carry this information ________

Answer 32

centrally

Question 33

The receptors for olfaction can be found in the ______ portion of the nasal cavity

Answer 33

superior

Question 34

Despite the wide diversity of smells that can be detected, there is only believed to be a _______ messenger mechanism utilized by the olfactory system

Answer 34

1 second

Question 35

________ in the olfactory epithelium are responsible for the formation of new receptor cells

Answer 35

Basal cells

Question 36

Which cells function similar to glial cells, providing nutrients and assisting the function of the olfactory receptor cells

Answer 36

supportive cells

Question 37

The ________ also produce mucus, which is necessary for the collection and detection of odorant molecules

Answer 37

support cells

Question 38

Dendrites of the olfactory receptor cells project into this ______ layer

Answer 38

mucus

Question 39

Odorants bind to receptors on the dendrites and initiate changes in ______ that lead to _______

Answer 39

ion flux ; depolarization

Question 40

If the depolarization initiated by an odorant binding is of a significant enough magnitude, an ________ is generated in the axon of the __________ cell

Answer 40

action potential ; olfactory receptor

Question 41

The electrical signal generated in the axon of the olfactory receptor cell is propagated via the ________ nerve to the _________

Answer 41

olfactory ; olfactory bulb

Question 42

It appears that all olfactory neurons utilize the same ________ pathway to initiate depolarization

Answer 42

second-messenger

Question 43

The binding of an odorant to a G-protein coupled receptor activates a G-protein called

Answer 43

Golf

Question 44

The _____ subunit of Golf exchanges a bound _____ for _____

Answer 44

alpha ; GDP ; GTP

Question 45

The activated _____ subunit dissociates from the _______ complex, and the alpha subunit activates _______

Answer 45

alpha ; beta-gamma ; adenylyl cyclase

Question 46

Adenyl cyclase converts _____ into _____

Answer 46

ATP ; cAMP

Question 47

cAMP binds to, and opens a

Answer 47

non-specific cation channel

Question 48

Sodium and calcium flow _____ their electrochemical gradients into the ________

Answer 48

down ; olfactory receptor cell

Question 49

The INFLUX of calcium activates a

Answer 49

chloride channel

Question 50

Olfactory cells are unique in that they contain a HIGH concentration of

Answer 50

chloride

Question 51

Chloride flows ____ of the cell, producing a _______

Answer 51

out ; depolarization

Question 52

If the graded potential produced during the second-messenger pathway is of significant enough magnitude, an _______ is generated in the ________ of the axon

Answer 52

action potential ; initial segment

Question 53

The frequency of these action potential is proportional to the

Answer 53

concentration of the odorant