Physiology Of Taste

Question 1

What structure & what cell detects taste

Answer 1

Chemoreceptors in taste buds

Question 2

Taste buds strcuture

Answer 2

Chemoreceptors separated by support cells, arranged like orange slices

Question 3

Taste bud life span

Answer 3

Around 10 days

Question 4

What do chemoreceptors do once they detect a taste

Answer 4

Synapse with afferent nerve fibres

Question 5

Where are taste buds located in the oral cavity

Answer 5

Mainly in tongue but also palate, epiglottis & pharynx

Question 6

What structure are most taste buds a part of

Answer 6

papillae on the dorsum of the tongue

Question 7

What three types of papillae contain taste buds

Answer 7

Fungiform, vallate, foliate

Question 8

Process of taste. STEP 1 Binding of taste provoking chemical (tasant) to ___________ produces ___________ receptor potential

Answer 8

Binding of taste provoking chemical (tasant) to receptor cells (chemoreceptors) produces depolarising receptor potential

Question 9

Process of taste. STEP 1 Receptor potential initiates action potentials in _____________ which synapse with receptor cells

Answer 9

Receptor potential initiates action potentials in afferent nerve fibres which synapse with receptor cells

Question 10

Process of taste. STEP 3 Signals conveyed by _________ via brainstem and thalamus to ______________

Answer 10

Signals conveyed by cranial nerves via brainstem and thalamus to cortical gustatory areas

Question 11

What three cranial nerves carry afferent taste fibres to the brain stem

Answer 11

CN VII (chorda tympani branch), CN IX, CN X

Question 12

What part of the oral cavity does the CN VII supply special sensory (taste) to

Answer 12

anterior 2/3 of tongue

Question 13

What part of the oral cavity does the CN IX supply special sensory (taste) to

Answer 13

Posterior 1/3 of tongue

Question 14

What part of the oral cavity does the CN X supply special sensory (taste) to

Answer 14

Areas other than tongue e.g. epiglottis & pharynx

Question 15

What are the 5 primary tastes

Answer 15

Bitter (alkaline, poisons etc), sour (acidic), salty (NaCl & other salts), sweet (glucose), umami (meat/ savoury - AAs)

Question 16

Define aguesia

Answer 16

loss of taste function

Question 17

Define hypogeusia

Answer 17

Reduced taste function

Question 18

Define dysgeusia

Answer 18

Distorted taste function

Question 19

Aguesia aetiology examples

Answer 19

Nerve damage, local inflammation, certain endocrine disorders

Question 20

Hypogeusia aetiology examples

Answer 20

Chemotherapy, medications e.g. metronidazole

Question 21

Dysgeusia aetiology examples

Answer 21

glossitis, gum infections, tooth decay, reflux, chemotherapy, neoplasms, zinc deficiency