Olfaction & Gustation Flashcards
what portion of detected odors are “noxious” and “pleasant?”
80% noxious
20% pleasant
where is olfactory epithelium located?
upper nasal cavity and around cribiform plate of ethmoid bone
what 3 cell types make up the olfactory epithelium?
- Basal cells
- olfactory receptor cells
- supporting cells
what are basal cells?
epithelial stem cells that will become new receptor cells
what are olfactory receptor cells?
bipolar cells whose dendrites bind to odorants and unmyelinated axons from the olfactory nerve
the olfactory nerves go through the ____ to synapse with ____ in the olfactory bulb
cribiform plate
mitral & tufted cells
olfactory bulb fibers run in the ____ which divides into…
olfactory tract
medial & lateral olfactory stria
the medial olfactory stria reaches the ____ via the ____
opposite olfactory bulb
anterior commissure
the lateral olfactory stria projects to the ____
primary olfactory cortex
describe the location of the primary olfactory cortex
- anterior portion of parahippocampal gyrus surrounding amygdala
- includes piriform & entorhinal cortex
the olfactory system is considered a subdivision of the ____ system
limbic
the piriform cortex relays information to the ____ and ____
orbitofrontal olfactory cortex
dorsomedial thalamic nucleus
what are the second order neurons of the olfactory pathway?
olfactory bulb fibers
a taste bud is a collection of ____ on a papilla of the tongue
gustatory receptor cells
what type of cell are CNs VII, IX, and X?
pseudounipolar
central axons from CNs VII, IX, and X synapse with the ____
solitary nucleus
where do CNs VII, IX, and X carry taste from?
VII: anterior 2/3 tongue
IX: posterior 1/3 tongue
X: epiglottis
cell bodies of fibers carrying taste in CN VII are located in the ____
genicular ganglion
cell bodies of fibers carrying taste in CN IX are located in the ____
inferior ganglion
cell bodies of fibers carrying taste in CN X are located in the ____
inferior-nodose ganglion
secondary afferents carrying taste form the ____
solitary tract
the solitary tract ascends through the ____ and synapses with the ____
brainstem
ventral posteromedial thalamic nucleus
taste fibers that synapse in the ventral posteromedial thalamic nucleus, then travel through the ____, ending in the ____
posterior limb of internal capsule
primary gustatory cortex
where is the primary gustatory cortex located?
inferior portion of postcentral gyrus, operculum, and superior portion of insula
transduction mechanism of salty tastes
Na+ channels
transduction mechanism of sour tastes
H+ channels
transduction mechanism of sweet tastes
2nd messenger system
transduction mechanisms of bitter tastes
- 2nd messenger system
- block K+ channels
transduction mechanism of umami tastes
broken down AAs, bind to receptors on Na+ channels
where are most bitter taste buds located on the tongue?
near the back
where are most sour taste buds located on the tongue?
sides
where are most sweet taste buds located on the tongue?
front/sides
where are most salt taste buds located on the tongue?
front/sides
