Olfaction & Gustation

Question 1

what portion of detected odors are “noxious” and “pleasant?”

Answer 1

80% noxious
20% pleasant

Question 2

where is olfactory epithelium located?

Answer 2

upper nasal cavity and around cribiform plate of ethmoid bone

Question 3

what 3 cell types make up the olfactory epithelium?

Answer 3

1. Basal cells
2. olfactory receptor cells
3. supporting cells

Question 4

what are basal cells?

Answer 4

epithelial stem cells that will become new receptor cells

Question 5

what are olfactory receptor cells?

Answer 5

bipolar cells whose dendrites bind to odorants and unmyelinated axons from the olfactory nerve

Question 6

the olfactory nerves go through the ____ to synapse with ____ in the olfactory bulb

Answer 6

cribiform plate
mitral & tufted cells

Question 7

olfactory bulb fibers run in the ____ which divides into…

Answer 7

olfactory tract
medial & lateral olfactory stria

Question 8

the medial olfactory stria reaches the ____ via the ____

Answer 8

opposite olfactory bulb
anterior commissure

Question 9

the lateral olfactory stria projects to the ____

Answer 9

primary olfactory cortex

Question 10

describe the location of the primary olfactory cortex

Answer 10

• anterior portion of parahippocampal gyrus surrounding amygdala
• includes piriform & entorhinal cortex

Question 11

the olfactory system is considered a subdivision of the ____ system

Answer 11

limbic

Question 12

the piriform cortex relays information to the ____ and ____

Answer 12

orbitofrontal olfactory cortex
dorsomedial thalamic nucleus

Question 13

what are the second order neurons of the olfactory pathway?

Answer 13

olfactory bulb fibers

Question 14

a taste bud is a collection of ____ on a papilla of the tongue

Answer 14

gustatory receptor cells

Question 15

what type of cell are CNs VII, IX, and X?

Answer 15

pseudounipolar

Question 16

central axons from CNs VII, IX, and X synapse with the ____

Answer 16

solitary nucleus

Question 17

where do CNs VII, IX, and X carry taste from?

Answer 17

VII: anterior 2/3 tongue
IX: posterior 1/3 tongue
X: epiglottis

Question 18

cell bodies of fibers carrying taste in CN VII are located in the ____

Answer 18

genicular ganglion

Question 19

cell bodies of fibers carrying taste in CN IX are located in the ____

Answer 19

inferior ganglion

Question 20

cell bodies of fibers carrying taste in CN X are located in the ____

Answer 20

inferior-nodose ganglion

Question 21

secondary afferents carrying taste form the ____

Answer 21

solitary tract

Question 22

the solitary tract ascends through the ____ and synapses with the ____

Answer 22

brainstem
ventral posteromedial thalamic nucleus

Question 23

taste fibers that synapse in the ventral posteromedial thalamic nucleus, then travel through the ____, ending in the ____

Answer 23

posterior limb of internal capsule
primary gustatory cortex

Question 24

where is the primary gustatory cortex located?

Answer 24

inferior portion of postcentral gyrus, operculum, and superior portion of insula

Question 25

transduction mechanism of salty tastes

Answer 25

Na+ channels

Question 26

transduction mechanism of sour tastes

Answer 26

H+ channels

Question 27

transduction mechanism of sweet tastes

Answer 27

2nd messenger system

Question 28

transduction mechanisms of bitter tastes

Answer 28

1. 2nd messenger system
2. block K+ channels

Question 29

transduction mechanism of umami tastes

Answer 29

broken down AAs, bind to receptors on Na+ channels

Question 30

where are most bitter taste buds located on the tongue?

Answer 30

near the back

Question 31

where are most sour taste buds located on the tongue?

Answer 31

sides

Question 32

where are most sweet taste buds located on the tongue?

Answer 32

front/sides

Question 33

where are most salt taste buds located on the tongue?

Answer 33

front/sides