8 Taste and Smell

Question 1

What is Ageusia?

Answer 1

total taste loss

Question 2

What is Anosmia?

Answer 2

total smell loss

Question 3

Why are chemotherapy agents risky for taste and smell?

Answer 3

inhibit the production of new cells

contain heavy metals (metallic taste)

Question 4

What 4 things might damage smell?

Answer 4

epilepsy
damage to olfactory bulb
parkinson’s diseases
clinical depression

Question 5

What are the 5 basic tastes?

Answer 5

salt
sour
sweet
bitter
umami

Question 6

What structure on the tongue do taste buds lie on?

Answer 6

papilla

Question 7

What are the components fo teh taste buds?

Answer 7

pore
taste cells
basal cells
sensory afferents

Question 8

How often are taste cells replaced?

Answer 8

2 weeks

born from basal cells

Question 9

How do taste cells detect taste?

Answer 9

chemical binds (transduction)
receptor potential
VGC Ca2+ channels open
Ca2+ influx
'neurotransmitter' released
excites sensory neurones
AP

Question 10

How is salt detected by taste cells?

Answer 10

Na+ entry (non-gated channels)

depolarisation

Question 11

How is salt detected?

Answer 11

H+ causes either K+ channel block or enters by TRP

depolarisation

Question 12

What channels facilitate salt sensing?

Answer 12

amiloride 0 sensitive sodium channels

Question 13

What is a TRP?

Answer 13

transient receptor potential

Question 14

What receptors are used to taste sweetness?

Answer 14

GCPR T1R2:T1R3

Question 15

What receptors are used to taste umami?

Answer 15

GCPR T1R1:T1R3

Question 16

Which receptors are used to taste bitterness?

Answer 16

GCPR T2R:T2R

Question 17

What is the central taste pathway?

Answer 17

gustatory sensory axons
cranial nerves
brain stem
thalamus (VPM)
primary gustatory cortex

Question 18

Name 2 secondary pathways of the central taste pathway and what they’re for

Answer 18

medulla (swallowing, salivation)

Hypothalamus (satiety, palatability)

Question 19

which cranial nerves offer taste sensation?

Answer 19

VII
IX
X

Question 20

How often are smell receptors replaced?

Answer 20

4-8 weeks

Question 21

How many types of chemoreceptor molecules does each olfacotry cell have?

Answer 21

one

Question 22

How many odorants can each chemoreceptor molecule bind?

Answer 22

many

Question 23

How do we work out what we are smelling?

Answer 23

population coding

Question 24

What is the principle of adaptation in smell?

Answer 24

constant regular smells are omitted (like home)

Question 25

Where in the brain are olfacotry neurones born?

Answer 25

lateral third ventricle

stem cells here

Question 26

How is smell detected?

Answer 26

odorant binds receptor
GCPR events
intracellular cascade
depolarisation
receptor potential
AP

Question 27

How do smell signals get frromt he nose to the brain?

Answer 27

1st order neurones (glomerulus, site where neurones detecting the same sort of cell synapse)
2nd order neurones

Question 28

What is the central olfacotry pathway?

Answer 28

olfacotry neurones
olfactory bulb
olfactory cortex

Question 29

Where does smell information go from the olfactory crotex? why?

Answer 29

MD thalamus - > orbitofronto cortex (recognition)

limbic area (association, bringing things together, being reminded of something)