Test 2: Smell and Taste Paths

Question 1

What CNs contribute to taste and smell

Answer 1

CN1 olfactory: smell

CNVII facial, IX glossophary, and X vagal: taste/gustation

Question 2

How many neurons make up olfaction path

Answer 2

2 neuron circtui with 5 destinations

Question 3

What are 1neuron characteristics of olfaction

Answer 3

bipolar unmyelinated chemosensitive

• embedded in mucosa of nasal epithelium
• intertwine as fascicle to form olfactory nerve
• project through ethmoid bone to olfactory bulb

Question 4

What are 2neuron characteristics of olfaction

Answer 4

in olfactory bulb
mitral and trufted cells within glomeruli
-go to 5 different targets

Question 5

Why is smell vulnerable to injury?

Answer 5

fascicles going through cribiform plate vulnerable to shear forces from head injury
-result in anosmia

Question 6

What makes up the olfactory nerve

Answer 6

single dendrite with unmyelinatef axon

• cilia hairs
• primary olfactory neyurons
• CB in olfactory epithelium

Question 7

What is in the glomeruli

Answer 7

dendrites and matrial/tufted cells (2neurons)

-each neuron cilia 1 picks up one oderant and translates into bulb

Question 8

What are the 5 targets of 2neurons of olfaction

Answer 8

anterior olfactor nucleus
olfactory tubercle
amygdala
piriform cortex
entorhinal

Question 9

What occurs at the anterior olfactory nucleus

Answer 9

sharpen sensory detection

• contralateral anterior olfactory nucleus and bulb input
• coordinates between bulbs

Question 10

What occurs at the olfactory tubercle

Answer 10

visceral and metabolic responses to smell

-hypothalamus, lateral stria-perforated substence-frontal-hypo

Question 11

What occurs at the amygdala

Answer 11

emotional response to smell

-limbic system- lateral to uncus in temporal lobe

Question 12

What occurs in the piriform cortex

Answer 12

concious perception- PRIMARY olfactory cortex

-orbital frontal gyri; anterior to parahippacampus- uncus

Question 13

What occurs in the entorhinal

Answer 13

memories and forming new ones

-hippocampus- primary gateway

Question 14

Where does the olfactory tract relay to?

Answer 14

Allocortex (

Question 15

What is the area where the2neurons deccusate called

Answer 15

anterior commisure

-medial striate through here

Question 16

Where do higher order smells get translated

Answer 16

primary olfactory output -> orbitofrontal cortex for high order analysis
-orbitofrontal crosses with taste modalitis to get smell

Question 17

How is taste transduced?

Answer 17

By gustatory receptors clustered in tastebuds

• trasnduce sweet, sour, salty, bitter, and umami
• excite pseudounipolar sensory 1neurons for that specific taste

Question 18

What portions of the mouth do the 3 CN involved in taste transduce?

Answer 18

Facial (VII)- aka corda tempony- intermediate facial

• anterior 2/3 tongue
• 1CB genicular ganglion

Glossopharyngeal (IX)

• posterior 1/3 tongue and pharynx
• 1CB inferior pharyngeal ganglia

Vagus (X)

• larynx, epilottis
• 1CB inferior vagal ganglia

Question 19

What are taste receptor cells

Answer 19

saliva will come and bring taste cells throughout mouth down into trenches where taste buds are

Question 20

What are the 3 type of taste buds and where are they

Answer 20

Circumvallae papilae: IX BITTER
-big posterior
-50% all tastebuds
Foliate papilae: IX SOUR
-deep latearl
-25% all tastebuds
Fungiform papilae: VII SWEET/UMAMI/SALTY
-front
-25% all tastebuds

Question 21

What is 1CB of taste

Answer 21

genicu gang for facial

inferior gang for glosso and vagal

Question 22

Where does 1neuron go and where does synapse on 2CB for taste

Answer 22

Travel in solitary tract to solitary nucleus in medulla

Question 23

Where are 2CB for taste

Answer 23

ROSTRAL Solitary nuclues -rostral medulla

Question 24

Where do 2CB go for taste

Answer 24

travel ipsilaterally in central tegmentum path to VPM

Question 25

Where are 3CB of taste

Answer 25

VPM
travel to primary gustatory cortex (insula) or orbital frontal operculum
-via internal capsule and coronar radiate

Question 26

What is the difference in proccessing of primary gustatory cortex vs, orbital frontal gyrus

Answer 26

Primary: discriminative taste
Operc: enhance descrimination with smell

Question 27

Where is the solitary tract/nucleus for taste

Answer 27

ROSTRAL medulla

• caudal is visceral sensory
• nucleus is on outside of tract