Chemosensation

Question 1

taste receptor morphology

Answer 1

modified epithelial cell located inside a taste pore. Synapses on CN 7, 9, or 10 ganglion fiber

Question 2

Conscious taste neural pathway

Answer 2

Taste bud –> cranial nerve –> solitary tract nucleus –> VPM thalamus –> insular cortex

Question 3

role of trigeminal nerve in chemosensation

Answer 3

chemesthesis (detection of noxious stimuli). Free nerve ending of CN 5 ganglion cell –> SpV

Question 4

smell receptor morphology

Answer 4

ciliated bipolar neurons

Question 5

How is an odor identified?

Answer 5

via a recognized pattern of activity across olfactory glomeruli

Question 6

What are the three types of gustatory papillae?

Answer 6

fungiform, foliate, circumvallate

Question 7

Describe fungiform papillae

Answer 7

anterior portion of tongue. chorda tympani branch of CN 7 (anterior 2/3 of tongue)

Question 8

Describe foliate papillae

Answer 8

on sides of tongue. CN 9 innervation

Question 9

Describe circumvallate papillae

Answer 9

Posterior tongue. CN 9 innervation

Question 10

Where are the taste receptors innervated by CN 10?

Answer 10

oropharynx

Question 11

5 primary taste qualities

Answer 11

sweet, sour, salty, bitter, umami (savory, MSG)

Question 12

Which taste qualities are transduced via ion channels?

Answer 12

salty and sour

Question 13

Which taste qualities are transduced via GPCRs?

Answer 13

sweet, bitter, umami

Question 14

Describe the orthonasal route of odorant access to olfactory epithelium

Answer 14

in through nostrils –> olfactory epithelium

Question 15

describe the retronasal route of odorant access to olfactory epithelium

Answer 15

mouth –> oropharynx –> nasopharynx –> olfactory epithelium

Question 16

Odor transduction pathway

Answer 16

Odorant binds receptor –> G protein activation –> cAMP –> influx of Na (depolarization) and Ca –> opened Ca-gated Cl channels –> Cl efflux –> further depolarization –> activated olfactory glomeruli

Question 17

Olfactory pathway for memory

Answer 17

olfactory bulb –> entorhinal cortex –> hippocampus –> memories

Question 18

Olfactory pathway for conscious perception of smell

Answer 18

Olfactory bulb –> piriform cortex –> orbitofrontal cortex –> conscious perception of smell

Question 19

Olfactory pathway for visceral reactions and homeostasis

Answer 19

Olfactory bulb –> olfactory tubercle and amygdala –> hypothalamus –> visceral reactions and homeostasis