Lecture 10 Flashcards
Taste chemicals are soluble in what 2 things
Water and air
What do taste and smell detect
Chemicals
In the case of smell what are the chemicals soluble in
Air
What kind of receptors do taste and smell chemicals rely on
G protein couples receptors
T/f taste and smell are closely related to behavior
True
What is the importance of nostrils
Important for distinguishing the location of odors
The inability of smell is called
Anosmia
What is a likely cause of Anosmia
A missing gene for that odor or a zinc deficiency
The inability to smell any odors could be due to
A cold, Brain trauma
Can you taste food without smell
No
What is our oldest sense
Taste
Things that you can smell are called
Odorants
What do odorants interact with
Olfactory receptor neurons
Where are orns located
Olfactory epithelium
where do the axons of the orns connect to
to the olfactory bulb
what kind of cells are orns
bipolar cells
are ORNS mylenated or unmylinated
unmylenated
what are the microvilia called on ORNS
olfactory cilia
olfactory cilia re directly exposed to what
odorants
how are ORNS regenerated
by stem cells
are ORNS regenerated
yes
how do cilia detect odors
they use their cilia
the odorant receptors are a large family of what kind of receptors
g protein linked receptors
are odor receptors variable
yes
how many odor receptors do humans have
950
who has better smell mice or humans
mice
how many odor genes are expressed in humans
400
each orn express how many olfactory receptors
1
t/f every olfactory receptor is expressed in some ORN
true
t/f ORNs not are selective
false
t/f ORNS expressing a particular receptor are sparsely distributed over the olfactory epithelium
true
where do ORN axons go to
the olfactory bulb
which has a larger olfactory bulb mice or humans
mice
in the olfactory bulb where do ORN axons go to
the glomeruli
in the bulb where axons go to the glomeruli they come in contact with 2 cells . what is the name of the cells
- mitral cells
2. tufted cells
mitral cells and tufted cell each extend dendrites into how many glomerulus
1
where do the axons of glomeruli project to
the olfactory tract
what kind of cells do glomeruli come in contacy with
granule cells
t/f only some of the ORNS expressing a particular receptor project to one glomerulus
false , they all do !
about how many ORN go into 1 glomerulous
25000
about how many mitral cells go into 1 glomerulous
25
t/f individual glomeruli are selective for particular odors
true
t/f different odors activate different glomeruli
true
t/f complex natural substances like coffee and cheese give off hundreds of odorant
true
at normal concentration , how many glomeruli are activated
only a small number of glomeruli are activated
what is the term when a small number of glomeruli only respond to one or 2 key odorants
sparse coading
what is population coding
many neurons respond but at different rates . you must compare response of many neurons to deduce which stimulus is present
how do axons from the olfactory bulb travel
ipsilaterally
describe the pathway that they axons from the olfactory bulb travel
travel ipsilaterally via the olfactory tract to the piriform cortex and other cortical targets
most mammals have another organ of smell called the
vomeronasal organ
where doe the vomeronasal organ project to
to the accessory olfactory bulb
where does the accessoty olfactory bulb project to
tothe hypothalamus and amygdala
name the 2 areas of the brain that are involved in emotion and body regulation
hypthalamus and amygdala
what are pheromones
they are odorants detected by the vno
how are pheromones detected
by receptors that are differnt from the ones used in the main olfactory system
t/f : pheromones are secreted in urine
true
t/f phermones exist in humans
false
t/f humans lack a vomeronassal organ
true
t/f there is differential activation of brain areas after exposure to an odor mix containing estrogen or androgens
true
t/f taste indicated the nutritive value of food
true
are most taste molecules hydrophilic or hydorphobic
hydrophillic
is the threshold for detecting bitter substances low or high
low
t/f the threshold for detecting bitter substances is high
false , its low
the threshold for detecting all substances except bitter is high/low
high
where are taste cells clustered
in taste buds
t/f there are taste buds on the pharynx
true
list the 5 places where taste buds are found
tongue palate pharynx epiglottis upper 3rd of esphagus
where are taste buds primarily foundon teh tongue
on the papillae
where are papillae embedded
in the epithelium
the tongue has special structures called ___ ___which contain taste bud
taste papillae
how many types of papillae are found in different regions of the tongue
3
where are fungiform papillae found
the anterior 2/3 of the tongue
what type of papillaw are found on the posterior 3rd of the tongue
cicumvallate papillae
each circumvallate is surrounded by a __
groove
where are foliate papillae are found where
situated on the posterior edge of the tongue
t/f tastes can only be detected in certain regions of the tongue
false, all tastes can be detected over the entire tongue
t/f different regions of the tongue have different sensitivities to taste
true
where is sour most sensitive on the tongue
on the sides
where is bitter most sensitive on the tongue
in the back
where is salty most sensitive on the tongue
on the sides and front
where is sweet / umami most sensitive on the tongue
on the tip
taste buds consist of what 2 kinds of cells
basal cells and taste cells
where are taste cells clustered
around the taste pore
each taste bud has a small opening at the surface of the epithelium called a
taste poor
taste cells in each bud extend ___into the taste taste poor
microvili
the taste cell in innervated by sensory neurons called
primary gustatory afferent fibers
what are the 5 basic tastes
salt, sour, sweet, bitter, umami
which taste is poisionous food often associtaed with
bitter
how many taste receptors are there
5
t/f there is 1 taste receptor for each basic taste
true
t/f each taste cell only expresses one type of taste receptor
true
t/f each taste bud is specific for one taste
true
the salt receptor is channel selective for __
na
in the salt receptor what depolarizes the cell
na
the sour receptors: what directly depolarizes the cell
h+
what are the sour receptors permiable to
protons and cations
sweet and umami use the g protein ____
gustducin
what are the receptors that are used in sweet
t1R2 and T1R3
what are the receptors that are used in the umami
t1R1 and T1R3
what are t1 , t1r2 ,t1r3
gpcr subunits
are t1r2 and t1r1 expressed in the same cell
no
does bitter use the g protein gustaducin
yes
what does gustaducin activate
PLCbeta 2
when gustducin activates PLCbeta2 ca is released which then activates ___
TRPM5
T/F trpm5 is a selective cation channel
false, trpm5 is a non selective cation channel
when trpm5 is opened does the cell depolarize or hyperpolarize
depolarize
when trpm5 is activated are channels opened or closed
opened
when taste cells are depolarized what does this lead to
neurotransmitter release
what are the taste cells transmitters
serotonin and maybe ATP , and GABA
t/f neurons that respond to similar tastes cluster together in hot spots
truth
t/f different basic tastes activate different parts of the insula
true
