Gustation and Olfaction

Question 1

Where are taste buds found?

Answer 1

Tongue
Palate
Tonsillar pillars 
Epiglottis
Proximal oesophagus

Question 2

What are the 3 types of papillae?

Answer 2

Circumvallate
Fungiform
Foliate

Question 3

What are the features of circumvallate papillae?

Answer 3

Located at the posterior of the tongue in a V shape

Large numbers of taste buds are found on the walls of these papillae

Question 4

What are the features of fungiform papillae?

Answer 4

Found at anterior surface of tongue

Taste bugs on surface of papillae

Question 5

What are the features of folate papillae?

Answer 5

Found on the lateral marginas are of the tongue

Question 6

Which cells differentiate into new taste cells?

Answer 6

Supporting cells

Question 7

What are the 5 taste categories?

Answer 7

Sour
Salty
Sweet
Bitter
Umami

Question 8

What is umami?

Answer 8

Taste caused by L-glutamate

Found in meats and aged cheese

Question 9

How does the taste threshold relate to different tastes?

Answer 9

Bitter and sour tastes have a much lower taste threshold than sweet and salty
This is because bitter and sour tastes are generally associated with more dangerous substances

Question 10

Which taste cells have metabotrophic pathways?

Answer 10

Sweet
Umami
Bitter

Question 11

Which taste pathways have ionotrophic pathways?

Answer 11

Salty

Sour

Question 12

What are the receptor cells in the olfactory system?

Answer 12

Bipolar neurons

Question 13

Describe the mechanism of the olfactory pathway

Answer 13

1. Odorant molecule binds to 7 transmembrane protein of primary olfactory neuron
2. Activated receptor activates a G-protein, which stimulates AC to convert ATP –> cAMP
3. cAMP activates the cation channel, making it permeable to sodium and calcium
4. Influx of cations causes depolarisation leading to APs

Question 14

What does the Bowman Gland secrete?

Answer 14

Mucus

Question 15

What forms the olfactory knob?

Answer 15

Lower end of bipolar neurons extending into mucus layer

Question 16

Which structure detects the odorants in the nasal cavity?

Answer 16

Olfactory cilia

Question 17

Which cells differentiate into bipolar cells?

Answer 17

Basal cells

Question 18

What connects bipolar neurons to the CNS?

Answer 18

Central processes

Question 19

Where does olfactory information from bipolar cells pass to?

Answer 19

Dendrites of mitral cells found in the neuropil of the glomeruli in the bulb

Question 20

Which cells provide lateral inhibition for signal enhancement of olfactory signals?

Answer 20

Tufted cells

Granule cells

Question 21

Which cells make dendritic connections between mitral cells?

Answer 21

Granule cells

Question 22

How many odour receptor genes does each bipolar neurone express?

Answer 22

1

Question 23

Name the 7 categories of odours

Answer 23

1. Camphoraceous
2. Musky
3. Floral
4. Pepperminty
5. Ethereal
6. Pungent
7. Putrid

Question 24

Which olfactory pathway feeds into the limbic system encoding the emotional aspects of odour?

Answer 24

Medial olfactory pathway

Question 25

What are causes of anosmia?

Answer 25

Nasal disease
Congenital 
Head trauma
Idiopathic
AD

Question 26

How can head trauma cause anosmia?

Answer 26

Damage to frontal lobe processin
Damage to ascending nerves at cribiform plate
Permanent compression of nasal passages