VIII- Taste, Smell

Question 1

5 primary sensations of taste

Answer 1

1. sour
2. salty
3. sweet
4. bitter
5. umami

Question 2

cranial nerves that transmit taste and olfactory

Answer 2

1. CN VII chorda tympani anterior 2/3
2. CN IX posterior 1/3

Question 3

taste receptor cells

Answer 3

taste buds = basal stem cells + taste cells with specific receptors @ apical domain

Question 4

olfactory receptor cells

Answer 4

highly unusual bc
1. have processes exposed to outside in epithelium
2. axons project directly to telencephalon/bulb
3. neurons continuously replaced
4. fire action potentials

Question 5

average life span of taste receptor cells

Answer 5

~10 days

Question 6

ionic mechanism of taste

Answer 6

1. dissolved substance initiates transduction
2. depolarization
3. SOME cells can fire action potential thru voltage gated Na+ channels
4. release transmitters

ligand gated ion channels + GPCRs

Question 7

olfactory transduction pathway

Answer 7

1. odorant molecule activated GPCRs in nerve receptors
2. neuron synapse on mitral cells (second order olfactory neurons) in bulb
3. bulb targets olfactory/pryiform cortex, olfactory tubercule, amygdala, entorhinal cortex
4. orbitofrontal cortex, thalamus, hypothalamus, hippocampus

Question 8

central projection pathway taste

Answer 8

1. taste receptor cell
2. first order gustatory neuron
3. second order gustatory neuron @ solitary tract
4. thalamus VPM
5. insular/gustatory cortex
6. amygdala

from solitary tract can also go straight to hypothalamus and amygdala

Question 9

hyposmia

Answer 9

dec or changed sense of smell
-transient or chronic

Question 10

anosmia

Answer 10

general: complete loss smell
specific: lowered sensitivity to specific odorant

Question 11

hypogeusia

Answer 11

dec taste sensation

Question 12

ageusia

Answer 12

absence of taste

Question 13

parageusia

Answer 13

aka dysgeusia
perversion of the sense of taste or bad taste in mouth