Olfaction_ Gustation

Question 1

basal cells

Answer 1

present in every taste bud

re differentiate every 7-14 day s into a taste cell receptor

Question 2

Taste bud histology

Answer 2

Each bud is innervated by either VII, IX, or X

DO NOT have axons, but have a very negative inside and can depolarize causing the entrance of Ca and release of NT

Labelled line or cross fiber

Question 3

Nucleus of solitary tracts

Answer 3

Found in the pons
receive primary afferents from ipsilateral taste buds (VII, IX, X) and from proprioception of V

fibers project to VPM on way to primary gustatory cx
also to DMN X for gag reflex

Question 4

primary gustatory cx

Answer 4

located in the insular cx

receives input from the VPM, which is receives input from the solitary nucleus which is where primary taste afferents synapse

**all ipsilateral

Question 5

How do 1000 odor receptors allow for discrimination of 10,000 odors

Answer 5

each odor receptor responds to multiple odorants

each odorant stimulates multiple receptors

a particular odorant activates a pattern of glomeruli

**combinatorial code=pattern of firing

Question 6

Central projections of olfaction

Answer 6

1) olfactory neurons in crib plate synapse on olfactory bulb
2) Olfactory bulb
3) anterior olf. nuc
3) piriform cx
4) amygdala
5) periamygdaloid cx
6) enterorhinal cx

Question 7

Projections of primary olfactory cx

Answer 7

hippocampus (memory)
thalamus---orbital frontal gyrus 
orbital frontal cx( directly) 
ipsi olfactory bulb 
hypothalamus (autonomics)

Question 8

Orbital frontal gyrus

Answer 8

aka flavor cx
aka orbital cx
receive input from the primary olfactory cx via thalamus

receives sensory input from the tongue and teeth, olfaction, vision, and gustation

determines if something is pleasant or unpleasant

Question 9

Phantosmia

Answer 9

hallucinated smell, often unpleasant

seizure with focal pt in olfactory cx areas (PHG or near uncinate)