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whats olfaction?
sense of smell
what does olfaction detect?
detect of chemicals in the air (ordorants)
what do humans use olfaction for?
identify food and quality of food (should I approach or avoid something in the environment?)
what can odorants do?
volatile (be able to float in the air) & are very small
what is the sensory organ of smell?
olfactory epithelium
where is the olfactory epithelium located?
inside the nasal cavity
what is the olfactory epithelium lined with?
olfactory receptor neurons which detect odorants that reach into the nasal cavity
when do olfactory neurons die off after about so the epithelium creates new ones?
a month
what routes do odorants reach the olfactory epithelium by two routes?
orthonasal olfaction and retronasal olfaction
what is the orthonasal olfaction?
odorant goes through the nostril
what is the retronasal olfaction?
odorant goes through the mouth and then nasopharynx (top of the throat) and then the nostrils
what other areas of the brain do odorants pass by?
amygdala, entorhinal cortex & hippocampus, piriform cortex
olfaction is the only sense that isnt processed in the?
thalamus
by what does the anterior (front) piriform cortex organize odorants?
chemical structure
by what does the posterior (back) piriform cortex organize odorants?
perceptual similarity
top down olfactory perception says that expectation and experience influences?
odor perception (expecation) and perception (experience)
what is ansomia?
inability to perceive smell
what can failing to sense smell be a warning sign of?
alzheimer
what is hyperosmia?
when smelling is enhanced; increase in olfactory sensitivity
who is typically better at discriminating odors?
women
what is gustation?
sense of taste that detects chemicals dissolving on our tongue
what are the 5 basic tastes of gustation?
sweet, sour, salty, bitter, umami
what do humans use gustation for?
identify food and quality of food such as ions (salty), energy (sweet), building blocks for proteins; amino acids (umami), bacteria/spoiled food (sour), toxic chemicals (bitter)
do we have a taste map on our tongue?
no
what is the tongue covered in?
papillae
what is embedded in the papillae?
taste buds that contain taste receptor cells
what do the receptor cells react to?
sweet, umami, bitter
what is the presynaptic cells?
salty, sour
salty and sour tastants are?
positively charged ions
where do sweet and salty tastants pass through?
ion channels and depolarize the taste cell cause an action potential
sweet and bitter tastants are?
sugars and other chemicals
what is activated from the swwet and bitter tastants?
G-protein coupled receptors that trigger events within the cell that eventually lead to depolarization and action potential
what do presynaptic (sour) cells react to as well?
carbonation and water
what are the pathways to the cortex?
Vagus Nerve (CN X), Glossopharyngeal Nerve (CN IX), Chorda Tympani Nerve (branch of facial nerve: CN VII)
the higher the concentration of a tastant means?
the more intense the taste
what is the quality of taste more likely coded by?
pattern of multiple neurons
what is the in the brain?
experience of taste
what influence taste perception?
adaptation, temperature, mouthfeel, visual, and auditory
gustation is carried to w here?
Carried to the brain via 3 cranial nerves
after gustation is carried to the brain via 3 cranial nerves, where does it go?
Nucleus of the solitary tract (medulla; midbrain)
where does the nucleus of the solitary tract carry gustation to?
thalamus
where does the thalamus take gustation to finally?
insular cortex (primary gustatory cortex)
