Physiology of Smell and Taste

Question 1

how are chemoreceptors stimulated

Answer 1

binding to particular chemicals

Question 2

where are the sensory receptors for taste mainly packaged

Answer 2

taste buds

Question 3

what are the sense organs of taste

Answer 3

taste buds

Question 4

what do taste buds consist of

Answer 4

sensory receptor cells and support cells

Question 5

how long is the life span of a taste bud

Answer 5

10 days

Question 6

what are taste buds replaced by when their life cycle runs out

Answer 6

basal cells within taste buds

Question 7

what do taste receptor cells synapse with

Answer 7

afferent nerve fibres

Question 8

where are taste buds mainly present

Answer 8

tongue, palate, epiglottis and pharynx

Question 9

where do the majority of taste buds sit

Answer 9

papillae of tongue

Question 10

what do papillae appear as

Answer 10

little raised red dots

Question 11

what are the 4 types of human papillae

Answer 11

filiform, fungiform, vallate, foliate

Question 12

what are the most numerous type of human papillae

Answer 12

filiform

Question 13

what type of human papillae doesn’t contain taste buds

Answer 13

filiform

Question 14

what does the binding of taste provoking chemicals (tastant) to receptor cells cause

Answer 14

depolarising receptor potential

Question 15

what does the receptor potential initiate

Answer 15

action potentials in afferent nerve fibres which synapse with receptor cells

Question 16

where are signals conveyed to

Answer 16

cortical gustatory areas in brain

Question 17

what do afferent taste fibres reach the brainstem via

Answer 17

7th (chorda tympani branch), 9th and 10th cranial nerves

Question 18

what section of the tongue does chorda tympani sense from

Answer 18

anterior 2/3

Question 19

what section of the tongue does glossopharyngeal nerve sense from

Answer 19

posterior 1/3

Question 20

where does vagus nerve sense from

Answer 20

areas other than tongue e.g epiglottis and pharynx

Question 21

what are the 5 types of taste

Answer 21

bitter, sour, salty, sweet, umami

Question 22

what are the three abnormalities of taste

Answer 22

ageusia, hypogeusia, dysgeusia

Question 23

what does ageusia mean

Answer 23

loss of taste function

Question 24

what can cause ageusia

Answer 24

nerve damage, local inflammation or some endocrine disorders

Question 25

what does hypogeusia mean

Answer 25

reduced taste function

Question 26

what can cause hypogeusia

Answer 26

chemo, medications

Question 27

what does dysgeusia mean

Answer 27

distortion of taste function

Question 28

what can cause dysgeusia

Answer 28

many e.g glossitis, gum infections, medications, URTI’s

Question 29

what types of smells is CN 1 responsible for

Answer 29

common odours e.g rose, chocolate, vanilla

Question 30

what types of smells is CN 10 responsible for

Answer 30

chemical and non chemical stimulus (protective to lungs)