Taste and Olfaction

Question 1

Define ageusia, hypogeusia, dysgeusia, cacogeusia

Answer 1

A: Inability to taste
H: Decreased ability to taste
D: distorted ability to taste
C: sensation of bad taste in absence of appropriate gustatory stimuli

Question 2

Define tastant

Answer 2

any substance capable of stimulating the sense of taste

Question 3

Define anosmia, hyposmia, dysosmia, parosmia, phatosmia, agnosia

Answer 3

A: inability to detect odours
H: decreased ability to detect odours
D: distorted identification of smell
P: altered perception of smell without an odour present
P: perception of smell without odour present
A: inability to classify or contrast odour’s but detect

Question 4

Define taste pore

Answer 4

small apical opening in mucosal epithelium

Question 5

Define Labile

Answer 5

cells continually renewed opposite to permanent

Question 6

Define umami

Answer 6

pleasant savoury taste/ meaty taste

Question 7

Define nervous intermediate and what is it aka

Answer 7

nerve of Wrisberg/glossopalatine part of Facial nerve (VIII)

Question 8

What is the thalamus

Answer 8

structure within brain, above hypothalamus just above brain stem, main function is to relay motor and sensory signals to the cerebral cortex

Question 9

What are olfactory mitral cells? Where are they located? (name of location and if this is in PNS/CNS)

Answer 9

neurones part of the olfactory system located in the olfactory bulb in the CNS

Question 10

What shape is a taste bud? What is the shape of the cells? How many cells are there in one taste bud (range)?

Answer 10

Onion shaped
Spindle shaped
50-80

Question 11

Taste buds communicate to the oral cavity via…

Answer 11

taste pores

Question 12

What are the RECEPTOR cells divided into (3)?

Answer 12

Three types
Type 1
Type 2
Type 3

Question 13

What type of nervous pathway do these cells stimulate (aff or eff)? What two cranial nerves do these pathways eventually link to?

Answer 13

Afferent tast pathways

Trigeminal and facial

Question 14

Are these cells labile or permanent?

Do the have villus projections or not?

Answer 14

Labile and yes

Question 15

What 5 tastes can taste buds recognise?

Answer 15

sweet, sour, bitter, salt, umami

Question 16

Which type of cell is most common? And what percentage does it compose of all three cell types?

Answer 16

T1, 50%

Question 17

Function of T1 cells? (2)

Answer 17

Degrade/absorb NT

Transduction of salty taste

Question 18

Function of T2 cells? (1)
How are the apical ends of T2 cells joined?
What projects into the pores from their apical end?

Answer 18

sweet, bitter, umami tastes activate it
Apical ends of T2 cells joined together by junctional complexes
microvilli project into pores from their apical end

Question 19

Function of T3? (2)

Answer 19

Transduction of sour tastes

form synaptic junctions with nerve terminals

Question 20

Location of taste buds?

What papillae are they generally linked with (3)?

Answer 20

Located dorsum, lateral margin of tongue, palate and pharynx

Commonly linked with fungiform, foliate, circumvallate papillae

Question 21

What 4 eff/aff nerve supply d they get? (1 and 2 are part of what cranial nerve)

Answer 21

1) Chorda tympani nerve then nervus intermedus
2) Greater superficial petrosal nerve then nervus intermedus
3) Glossopharyngeal nerve
4) Vagus nerve
- 1 and 2 branches of facial nerve

Question 22

what is the perception of taste based on? 3

Answer 22

internal state, past experiences, genetics

Question 23

What does taste depend on?

Answer 23

smell and texture

Question 24

Roughly how many olfactory receptors are there? What type of receptor proteins are they?

Answer 24

1000, G-Coupled

Question 25

How thick is olfactory mucosa (cm)?

Answer 25

3cm

Question 26

What directs inhaled air towards olfactory epithelium?

Answer 26

Turbinates

Question 27

What 4 cells are found in olfactory epithelium?

Answer 27

olfactory receptor cells, supporting cells, basal cells, brush cells

Question 28

What do olfactory receptor cells do?

Answer 28

solublise odorants

Question 29

What nerve innervates olfactory epithelium?
Sensory/Motor?
Only sensory pathway that doesn’t relay in the …
Are olfactory nerve cells labile or permanent?

Answer 29

Olfactory nerve
sensory
thalamus
labile

Question 30

Nervous pathway of olfaction (4)

Answer 30

Olfactory epithelium
Olfactory bulb
Mitral cells
cortex of brain