Lecture 7- Taste Flashcards
taste
sensations evoked by solutions in the mouth that contact the receptors on the tongue and roof of the mouth
flavour
combination of true taste (sweet, salty, sour, bitter, umami) and retronasal olfaction
retronasal olfactory sensation
the sensation of an odour that is perceived when chewing and swallowing forces an odorant in the mouth up behind the palate into the nose
chemical senses
taste and smell
elements
substances that cannot be broken down into simpler substances (sort of)
chemicals
elements or combinations of elements
chemical compound
substance composed of 2 or more elements in a fixed proportion
odorant
basic stimulant for smell is a chemical compound called an odorant
tastant
basic stimulant for taste
papillae
bumps on our tongues
taste buds
found in the divots between papillae and they contain taste receptor cells
fungiform papillae
located throughout the tongue, but with the highest concentrations along the tip and the sides
- contain taste buds which are sensitive to all 5? tastes
filiform papillae
small and located throughout the tongue
- no taste buds!!! responsible for the tongue’s sense of touch
circumvallate papillae
humans usually have between 6-12 of these, sensitive to bitter tastes
foliate papillae
look like fish gills, located on side of tongue near the back
- lots of taste buds
solubilized
in order to be tasted, molecules is food must be dissolved (solubilized) by saliva
amylase enzyme
in saliva, breaks down starch and turns into sugar
taste pore
tips of taste receptor cells reach up into an opening, the :
Microvilli
“taste hairs”- tips of the taste receptor cells
approx how many taste receptor cells do humans have
300,000
four basic tastes: salty
made up of 2 charged particles: 1 cation 1 anion (sodium chloride)
- early experience can modify salt preference, perception changes over time
four basic tastes: sour
comes from acidic substances
- can damage body tissues at high concentrations
four basic tastes: bitter
cannot distinguish between tastes of different bitter compounds
- all bitter is bitter
- can be poisonous
- can “turn off” bitter perception
- intensifies during pregnancy for women
four basic tastes: sweet
evoked by sugars, many different sugars taste sweet
- single receptor type is responsible for all sweet perception ; different sweeteners stimulate different parts of receptors
glucose
principle source of energy for most animals
fructose
sweeter than glucose
sucrose
common table sugar; combo of glucose and fructose
umami
candidate for 5th basic taste
- comes from monosodium glutamate (MSG)
GLUTAMATE
IMPORTANT NEUROTRANSMITTER
safety issues of consuming MSG
numbness, headache, flushing, tingling, sweating, tightness in the chest if sensitive people consume a large amount
cross-modality matching
The human ability to match the intensities of sensations that come from different sensory modalities
- used to assess the intensity of taste sensations for non, medium, and supertasters
labelled lines
each taste receptor connects to a nerve fibre that signals a particular taste quality (separate nerves)
- suggests that info about taste qualities flows along specific and distinct paths:
nerves in the mouth gather into 3 bundles:
1 in from the front of the tongue (nerve VII)
1 from the back of tongue (nerve IX)
1 from throat (nerve X)
where do the nerves in the mouth travel to?
towards the medulla to an area called the nucleus of the solitary tract
what is responsible for these reflexes: gagging, coughing?
sensory nuclei in the nucleus of solitary tract
what order does taste info go through the brain?
nerves in mouth
the nucleus of solitary tract
thalamus
primary taste cortex (gustatory cortex)
* amygdala and hypothalamus
amygdala function
linking emotional states with memories
hypothalamus function
memory creation and storage
unconditioned stimulus
stimulus which generates a reflexive response: no learning required
unconditioned response
unlearned reflex elicited by the unconditioned stimulus
neutral stimuli
not responsive at first
conditioned stimulus
researchers
conditioned response
drool
biological preparedness
the central nervous system (CNS) and peripheral nervous system (PNS) are structurally hard-wired to make conditioned stimulus connections related to life-critical unconditioned stimuli, even with very limited learning opportunities
capsaicin
chemical that produces the burn in chilis ALSO desensitizes pain receptors
