ANAT neuroanatomy of taste and olfaction Flashcards

1
Q

5 sensations of taste
which release ATP
which release 5-HT

A
ATP:
    sweet
    umami
    bitter
5-HT:
    salty
    sour
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2
Q

what type of receptors are olfactory receptors

ionotropic/metabotropic

A

metabotropic

GPCR

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3
Q

what makes up CN 1 and pass through the cribriform plate

A

olfactory fila

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4
Q

what is the route through which centrifugal fibers reach the olfactory bulb

A

AC (ant. commisure?)

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5
Q

what does the olfactory tract contain

A

fibers of lateral olfactory tract
cells of anterior olfactory nucleus
fibers of anterior limb of anterior commisure

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6
Q

olfactory bulb layered forebrain structure

what layers are here [6]

A
olfactory epithelium (SUPERFICIAL)
olfactory nerve (after cribriform plate)
glomerular layer
external plexiform layer
mitral cell layer
granule cell layer (DEEP)
lateral olfactory tract
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7
Q

how does the glomerular layer receive input from other central nervous system areas

A

centrifugal afferents

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8
Q

what is the principle interneuron of the olfactory bulb

A

granule cell

inhibitory

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9
Q

f(x) of granule cells in the olfactory bulb

A

modulate olfactory bulb activity via feedback look

decrease activity of mitral and tufted cells

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10
Q

what is a hallmark of the olfactory bulb
(for the most part)
what is the exception

A

projects directly to the cortex
does not relay via thalamus

piriform cortex

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11
Q

what forms the lateral olfactory tract

where does it terminate

A

axons of mitral and tufted cells from caudal olfactory bulb

terminate on olfactory cortex (ventral areas of telencephalon)

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12
Q

areas of the olfactory cortex

A
anterior olfactory nucleus
olfactory tubercle
piriform cortex
anterior cortical amygdaloid nuclues
periamygdaloid cortex
lateral entorhinal cortex
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13
Q

where is olfactory information relayed to

???

A
insular and obitofrontal cortices
dorsomedial nucleus (thalamus)
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14
Q

f(x) of orbitofrontal cortex

A

integrate olfactory, taste, and other food-related cues that produce experience of flavors

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15
Q

after being relayed where is olfactory information directed to
???

A

lateral hypothalamus and hippocampus

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16
Q

where does the lateral hypothalamus get its inputs from?

f(x)?

A

piriform cortex and anterior olfactory nucleus

important for feeding behavior

17
Q

where does the hippocampus get its inputs from?

f(x)?

A

entorhinal cortex

links olfactory input to learning and behavior

18
Q

anosmia

A

loss of smell

19
Q

hyposmia or olfactory hypesthesia

A

decreased sensitivity to odorants

can be associated w/ nasal polyps

20
Q

what does the chorda tympani of CN VII innervate in the peripheral taste pathway

A

fungiform papillae on anterior 2/3 of tongue

anterior foliate papillae

21
Q

what does the greater superficial petrosal nerve innervate in the peripheral taste pathway

A

taste buds on soft palate

22
Q

peripheral taste pathway

CN VII

A

enter brainstem @ pontomedullary jxn via intermediate nerve (CN VII) –> solitary tract (CN VII) –> target cells of solitary nucleus –> rostral portion of gustatory nucleus

GVA (caudal portion of gustatory nucleus)

23
Q

what does the lingual-tonsillar branch of CN IX innervate

A

taste buds in vallate papillae

posterior foliate papillae

24
Q

what does the superior laryngeal nerve of CN X innervate

A

taste buds of epiglottis and esophagus

25
Q

where are the cell bodies of the taste fibers of CN IX, X found

A

inferior ganglia (petrosal [IX] and nodose [X])

26
Q

peripheral taste pathway

CN IX

A

central processes enter medulla –> descend in solitary tract –>terminate on neurons in rostral portion of gustatory nucleus

27
Q

hallmark of the central taste pathway

A

exclusively ipsilateral

28
Q

central taste pathway

A

2nd order neurons travel via ipsilateral central tegmental tract –> parvicellular ventral posteromedial nucleus (VPMpc)

3rd order neurons travel via ipsilateral posterior limb of IC –> inner portion of frontal operculum and anterior insular cortex (rostral area of bradmann 3b on postcentral gyrus)

29
Q

what pathway is responsible for discriminative aspects of taste

A

central taste pathway

solitary nucleus –> VPMpc –> cortex

30
Q

lesion of root of CN VII or tumor in internal auditory meatus (vestibular schwannoma)

A

loss of taste from ipsilateral 2/3 of tongue
paralysis of ipsilateral facial muscles
hyperacusis (paralysis of stapedius m)
impaired secretion of glands

31
Q

damage distal to geniculate ganglion

A

may or may not result in taste loss depending on origin of chorda tympani branches

ipsilateral facial paralysis

32
Q

ageusia
hypogeusia
parageusia (dysgeusia)

A
  • complete loss of taste
  • decreased taste sensitivity
  • distortions of taste perception