olfactory and taste Flashcards
taste vs temperature/touch innervation of the anterior tongue
taste: chorda tympani (CN VII)
touch/temp: lingual n. (CN V-3)
posterior tongue innervation of taste/temp/touch
glossopharyngeal n. (CN IX)
What’s the least understood sense?
smell
Olfactory membrane is located on
superior part of each nostril
type of receptor on the cilia of olfactory cells
odorant-binding protein receptors
Binding of chemical odorant to receptor induces the _____ transduced formation of cAMP which opens _____ channels
Binding of chemical odorant to receptor induces the “G-protein” transduced formation of cAMP which opens “sodium” channels
Odorant-binding receptors are located on the
cilia of olfactory cells
Odorant-binding receptors on olfactory cell cilia actions
Binding induces G-protein
activation of adenyl cyclase
causes formation of cAMP
cAMP opens sodium channels
causing depolarization
substances must be sightly _____ to penetrate the mucus to reach the olfactory cells
water-soluble
anosmia
loss of smell
trauma to the cribriform plate that shears the olfactory axons is called
anosmia (loss of smell)
rhinorrhea
nasal congestion
anterior 2/3 of tongue sensation and taste innervation
posterior 1/3 of tongue sensation and taste innervation
anterior:
sensation - lingual n. CN V-3
taste - chorda tympani (CN VII)
posterior:
sensation - CN IX
taste - CN IX
posterior 1/3 of tongue sensation and taste innervation
sensation - CN IX
taste - CN IX
anterior 2/3 of tongue sensation and taste innervation
anterior:
sensation - lingual n. CN V-3
taste - chorda tympani (CN VII)
13 possible chemical receptors in taste buds
*2 for sodium
* 2 for potassium
* Chloride
* Adenosine
* Inosine
* 2 sweet
* 2 bitter
* Glutamate
* Hydrogen ion
sour taste perception caused by
Caused by H+ from acids (citric acid, acetic acid)
salty taste perception caused by
ionized salts, mainly sodium (NaCl)
sweet taste perception caused by
sucrose
many chemicals - mostly organic
umami taste perception cause by
glutamate
bitter taste preception caused by
long chain organic substances (N)
alkaloids
how does age impact bitter taste preception
younger is more sensitive to bitter taste sensation
taste buds are located on what?
papillae of tongue
Circumvallate papillae form a “ “
V
where are 50% of taste buds found?
Circumvallate papillae
taste bud distribution on papillae
Circumvallate papillae 50%
Foliate papillae 25%
Fungiform papillae 25%
location of tongue papillae
Circumvallate papillae – posterior surface of tongue
Foliate papillae – along lateral surfaces of tongue
Fungiform papillae – flat surface of tongue
most numerous of the lingual papillae are the
filiform papilae
what papillae is responsible for giving the tongue its texture and sensation of touch?
filiform papillae
what is the average life of a taste bud?
10 days
salts, sweet, sour, and umami tastes cause _____ of the respective taste cells
depolarization
bitter taste causes an internal release of ____
Ca2+
(no external Ca2+ required)
transmission of taste sensation (starting at taste buds)
anterior 2/3 CN VII
posterior 1/3 CN IX
posterior of mouth CN X
->
signals to solitary nucleus
->
thalamus
->
cortex
gustatory cortex contains (2)
insula (in synovial fissure)
frontal operculum (near insula)
taste and smell are tied to primitive ____ and _____ functions of the NS
emotional and behavioral
most of what is perceived as a sense of taste is actually derived from ___
smell
glutamate is thought to be a primary tastant of which of the following taste sensations?
umami
What substance stimulates the sour taste sensation?
hydrogen ions
which of these is NOT a primary smell sensation?
ethereal
floral
camphoraceous
umami
umami
what are the primary smell sensations?
musky
putrid
pungent
camphoraceous
ethereal
floral
pepperminty
the first central synapse for neurons transmitting the sweet taste sensation is in the nucleus of what?
solitary tract
the facial nerve is responsible for the innervation of what? (in relation to taste)
anterior 2/3 of tongue
*chorda tympani
What follows the activation of an odorant receptor in the transduction mechanism of smell?
G-protein activation of adenyl cyclase
what CN is involved primarily in olfaction?
CN I
a woman comes home and detects a strong smell of gas but her husband has been home all day and does not smell anything. What condition describes the husband?
anosmia
where are odorant binding receptors found?
cilia
lack of taste refers to
ageusia
in the olfactory transduction mechanism, what ions have increased conductance?
sodium
