Section 3 Taste and Olfaction Flashcards
What taste modalities warn against potential noxious chemicals?
Sour and bitter
Which 3 tastes rely on G-protein-coupled receptors?
Sweet, umami and bitter
Which taste modaity is T1R2 + T1R3?
Sweet
Which taste modality is T1R1 + T1R3
Umami
What protein is the same bw the sweet and umami receptors?
T1R3
Which taste modality is the T2R family?
Bitter
How are different better substances detected?
By diff members of the TR2 family of receptor.
Which tastes are type II cells assoc w?
sweet/bitter/umami
What NT is released by the sweet, bitter, umami modalities?
ATP
Through what cells does sodium enter the cells of the tongue?
Amiloride-sensitive channels (depolarizes cell and leads to NT release)
How do H ions enter or the sour modality?
Via PKD2L1 ion channels
What ions shut down K channels?
H+ ions
How can taste be modified?
Leptin: released by fat cells in response to eating to give a sense of satiation, to damp response to sweet tastants OR
Increase levels of endocannabinoids: increase responses to sweet tastants
Supertasters:
heightened taste, esp. bitter, more fungiform papilla
Are there more men or women super tasters?
women, 35% of women vs 15% of men
What do super tasters tend not to like?
green veggies like cabbage and kale
How long do taste chemoreceptor cells live?
10 days
What do new taste cells differentiate from?
Basal cells near the base of taste bud
how does chemo affect taste?
kills all the taste cells and they won’t be replaced until after chemo is stopped
Ageusia:
loss of some or all tastants
Hypogeusia:
dec sensitivity to some or all tastants
Dysgeusia:
distortion of taste of some or all or the perception of taste when stimulant is not there (gustatory hallucination)
Gustatory agnosia:
complete
Hypergeusia:
inc taste sensitiivity to some or all tastants
Adrenal insufficiency is aka:
Addison’s disease
An example of hyperguesia:
Addison’s disease
How does adrenal insufficiency lead to a decrease in the threshold for salt taste?
dec secretion of aldosterone, dec renal Na-reabsorption, fall in plasma Na conc, fall in salivary Na, 100 X dec in threshold for salt taste
Loss of taste is common reported with:
D-penicillamin, a copper chelator (or other metals, too)
What is D-penicillamin used to tx?
cystinuria, scleroderma, RA and pulmonary fibrosis
Taste issues most often happen:
after an injury or illness
T or F? 3rd molar extraction can lead to tast disorders
T
Injury or illnesses that may cause taste disorders:
upper res and middle ear infections, head and neck cancers, chemical exposure (insecticides, some meds, some antibiotics and antihistamines), head injury, surgeries to ear, nose, and throat, poor oral hygiene
What taste buds decrease with age?
Fungiform
What types of receptors are in the fungiform taste buds?
All 5
T or F? Conc of salt required to get the same level of stimulation decreases w age.
F. increases. threshold increases
How do afferent officers respond to taste?
some respond more strongly to one taste modality than other fibers.
What combine to form the sense in the primary gustatory cortex?
olfactory, somatosensory, and taste input.
Secondary taste area:
taste, olfaction, water, oral temp, fat texture, viscoity, grittiness, particulate quality
To where do odors bind?
receps on the cilia of the olfactory receptor neurons
T or F? Each olfactory receptor neuron expresses many types of olfactory receptors.
F. one type
T or F. Some olfactory receptor neurons can be activated by multiple odorants.
T.
T or F? One odorant can activate multiple kinds of olfactory receptor neurons
T
What does odor identification entail?
different activities of a population of odor receptors
Olfactory cell turnover rate:
every 40 days
Chemo: lost sense of smell, will return about ___ days after stopping the tx
40
What is hyposmia a common sign of?
PD and AZ
What can cause anosmia?
PD, AZ, viral infection, concussion, brain trauma
loss of the sense of smell:
anosmia
Incorrect perception of smell:
parosmia (ie flowers smell like something burnign)
Perceiving a fould, rotten smell in the absence of any stimulus:
phantosmia
Phatosmia can occur when?
During epiliptic seizure that originates in the medial temporal lobe
A seizure originating here can lead to phantosmia:
medial temporal lobe
1-7% of Europeans can’t detect:
musk
What is more marked, the loss of taste or olfaction?
Olfaction
What has a bigger impact on taste, olfaction or gustatory input?
olfaction
___ kinds of olfactory cells, __ different kinds of glomerulus, all inputs to one glomerulus come from the same class of ______
300, 300, primary receptor cell
T or F? Neurons can respond to more than one type of odorant.
T
Half of the neurons in the orbitofrontal cortex:
are responsive to only one odor, and the rest to only a few
