Olfactory and Taste Flashcards
what bone is cribriform plate part of?
ethmoid
loss of ability to smell
anosmiac
only part of olfactory neuron that can respond to odorant
cilia
what makes up olfactory stria?
mitral and tufted cell
this leads to contralateral olfactory bulb
medial olfactory stria
what receives primary olfactory input?
amygdala, periamygdaloid complex, piriform cortex, entorhinal cortex
what part of thalamus would olfactory project to (secondarily)?
mediodorsal nucleus thalamus
where are taste buds primarily located?
circumvallate papillae
how many circumvallate papillae do we have?
8/12/2015
what makes up taste cortex?
operculum and insular cortex
germ layer for olfactory epithelium
ectoderm
this gave rise to olfactory epithelium, glial cells olfactory nerves and bulb
olfactory placode
type of epithelium olfactory is
pseudostratified columnar
beneath epithelium, secrete mucus in which odorants are dissolved
olfactory glands of Bowman
dendrite of bipolar olfactory neuron ends in epithelium as this (bulbous enlargement)…has cilia with odorant receptors
olfactory vesicle
these unmyelinated axons are bundled on each side of olfactory neuron
olfactory fila
where do olfactory fila terminate?
olfactory glomeruli (go thru cribriform plate to here from epithelium)
life span for healthy olfactory cells
30-60 days
these act as stem cells that give rise to receptor cells in olfactory epithelium
basal cells
layers of olfactory bulb from superficial to deep
nerve fiber, glomerular, external plexiform, mitral cell, granule cell
what makes up nerve fiber layer of olfactory bulb? where do these terminate?
afferent from olfactory epithelium; glomeruli
makes up glomeruli…olfactory receptor axons synapse on these dendrites
mitral and tufted cells
mitral and tufted cells have reciprocal connections with these cells
periglomerular cells
modulatory input to olfactory bulb glomerular layer
locus ceruleus, raphe nuclei, anterior olfactory nucleus, diagonal band of Broca
what makes up external plexiform layer of olfactory bulb?
somata of tufted cells, dendrites tufted and mitral cells, apical dendrites granule cell
principal cell type of olfactory bulb
mitral
what input do mitral dendrites receive in external plexiform layer?
centrifugal fibers of olfactory tract
these axons run in olfactory tract and comprise main output of the bulb
mitral cell
are mitral and tufted cells inhibitory or excitatory?
excitatory (probably glutamate)
principle interneuron of olfactory bulb
granule cell
two interneurons in olfactory bulb
periglomerular and granular cells
inputs to periglomerular cells
olfactory neuroepithelial cells, centrifugal fibers olfactory tract, dendrodendritic synapses w/ mitral
what do periglomerular cells secrete?
dopamine, GABA, peptides
NT for granule cells
GABA
granule cells receive axodendritic contacts from these cells
mitral cells and centrifugal fibers
an order arrives in a glomerulus and stimulates these cells…which then inhibit surrounding mitral cells (*surround inhibition*)
periglomerular cells
collateral branches of mitral/tufted cells axons terminate here (between olfactory bulb/tract)
anterior olfactory nucleus
this is located at rostral margin of anterior perforated substance…olfactory tract expands here
olfactory trigone
where do most axons that enter the olfactory trigone from the olfactory tract go?
lateral olfactory stria (to lateral olfactory area)
fibers that don’t enter lateral olfactory stria will go to here (*which is part of intermediate olfactory area*)
anterior perforated substance
principal cell axons pass through the olfactory tract and terminate here
primary olfactory areas (for subjective appreciation)
lateral olfactory tract (formed by mitral and tufted projections) gives rise to these; where does this project?
medial and lateral olfactory stria; contra. olfactory tract
anterior olfactory nucleus projects here
bilateral olfactory bulbs, contra. anterior olfactory nucleus
where does projection from olfactory bulb terminate?
primary olfactory cortex
these make up primary olfactory cortex; how many layers?
amygdaloid nuclear complex, olfactory tubercle, piriform cortex, entorhinal cortex; 3 layers
where does lateral olfactory stria terminate?
olfactory tubercle and piriform cortex
lateral olfactory stria projects here via amygdala
MD thalamus
lateral olfactory stria projects here for conscious perception of smell
orbitofrontal cortex
lateral olfactory stria projects here via the entorhinal cortex
hippocampus
where does lateral olfactory stria project?
MD thalamus, orbitofrontal cortex, hippocampus
where do anterior olfactory nucleus, olfactory tubercle, piriform cortex, anterior cortical amygdaloid nucleus, periamygdaloid cortex, and lateral entorhinal cortex project?
lateral hypothalamus, DM thalamus, insular and orbital cortex, olfactory bulb
olfactory cortex has direct connections with these
orbitofrontal and insular cortex
olfactory cortex has projections to these structures for feeding and learning/behavior
lateral hypothalamus and hippocampus
these make up pyriform cortex
uncus, entorhinal area, limen insulae
this is landmark of amygdala/lateral olfactory area on medial surface temporal lobe
uncus
this part of amygdala receives olfactory fibers; what is other part of amygdala part of?
dorsomedial; limbic system
principal region for conscious awareness of olfactory stimuli (*primary olfactory area*)
lateral olfactory area
this percent of human genome is for odorant receptors
3
what kind of receptors are odorant receptors?
GPCR
lesion of this will cause olfactory hallucinations
parahippocampal region
meningioma of olfactory groove compresses olfactory tract and optic neve
Foster Kennedy syndrome
how many chemoreceptor cells are located on taste bud?
40-60
what is turnover rate for gustatory receptor cells? what is source of new cells?
10-14 days; basal cells
taste buds located on lingual papillae
fungiform, vallate, folate papillae
how many taste buds do fungiform papillae include? (*anterior 2/3 tongue*)
2/4/2015
these papillae located on terminal sulcus; how many taste buds?
vallate; 8-12
this papillae located on lateral tongue (*only ONE…2-9 clefts*)
folate
these extend into taste pores…soluble chemicals interact with receptors here
apical microvilli
this taste occurs when chemical interacts with specific ion channel
salty
these tastes occur when chemical interactions with receptor activated GPCR second messenger pathway
sweet, sour, bitter
transduction of this in taste can be done thru ion channels or G protein pathways
amino acid
these SVA CN carry taste
VII, IX, X
where are first order neurons located for taste? where do these project?
geniculate, glossopharyngeal, vagal ganglia; solitary tract/nucleus
this CN innervates taste for anterior 2/3 tongue and palate; what nerves carry taste fibers? where are cell bodies?
VII; chorda tympani and GPN; geniculate ganglion
CN innervates vallate papillae and posterior 1/3 tongue; where are cell bodies?
IX; inferior ganglion
CN that innverates epiglottis for taste; what nerve carries taste fibers? where are cell bodies?
X; superior laryngeal; inferior ganglion
second order taste neurons from solitary tract travel in this; where do they terminate?
CTT; VPM thalamus
third order taste neurons from VPM thalamus travel through this; where do these fibers terminate?
posterior limb IC; frontal operculum (area 43), anterior insular cortex, rostral area 3b (discriminative taste pathway)
insular cortex projects here to get to hippocampal formation
entorhinal cortex (area 28)
complete loss of taste
ageusia
distortion of taste
parageusia
