Gustation Flashcards
What are senses?
Group of specialized receptors that responds to a specific physical phenomenon and that corresponds to a particular region of the brain where the signals are processed and interpreted.
Who formulated the doctrine of specific nerve endings?
Johannes Muller
What is the significance of Hermann Ludwig Ferdinand Von Helmholtz’s work?
All behaviour should be explained by only physical forces rather than vitalism.
Who proposed that neuron transmissions are chemical based?
Otto Loewi
What does the Absolute threshold refer to in psychophysics?
The minimum intensity of a stimulus that can be detected.
What is the Just noticeable difference?
The smallest change in stimulus intensity that can be detected.
What is the Method of limits in psychophysical methods?
A method where stimuli are presented in ascending or descending order to determine thresholds.
Define the Method of constant stimuli.
A method where a set of stimuli is presented in random order to determine thresholds.
What is the Method of adjustment?
A method where participants adjust the stimulus until it matches a criterion or threshold.
What does Fechner’s law represent?
Dp = dS/S, indicating that the perception of a stimulus is proportional to the logarithm of the stimulus intensity.
change in intensity/ initial stimuli = constant stimuli (webers contrast
In scaling methods, participants rate on a scale of how __________ they perceive something to be.
[intensely]
What type of taste is associated with Sucrose?
Presence of calories
What does sour taste (____acid) indicate?
Warning of spoilage
What does ______ chloride indicate in taste perception?
Presence of electrolytes to maintain body’s fluid balance
What does M__________ glutamate signify?
Presence of protein
At how many weeks of gestation do specialized taste cells begin to develop?
As early as 7 or 8 weeks
When are structurally mature taste buds visible?
At 13-15 weeks
How many taste buds do infants have compared to adults?
Up to 5 times the amount
What is the role of the tongue?
Muscular organ that plays vital parts to enable talking, chewing, swallowing.
What are papillae?
Small structures on the surface of the tongue that contain taste buds.
What is a taste bud?
Sense organ that contains receptors for the sense of taste.
What are taste receptors?
Taste receptors make up tastebuds, they have proteins on the surface of taste cells that bind with food molecules.
Taste receptors send signals to the brian via nerve fibres
What happens during depolarization of the taste cell?
Sodium increases within the cell and depolarises the membrane which opens a voltage gated calcium channel. Calcium increases in the cell which causes the release of neurotransmitter – this causes a change in the electric charge leading to release of a signal
Calcium increases within the cell and depolarizes the membrane.
What is the sequence of neural signals for taste perception?
Tongue, papillae, taste buds, taste recpetors, depolarisation, neurotransmitter release, brain stem (nucleus solitary tractus), thalamus (relay station), Primary cortex (insula), secondary cortex (orbitofrontal cortex)
What are the four types of papillae?
- Filiform
- Fungiform
- Foliate
- Circumvallate
Where are filiform papillae located?
On the upper surface of the tongue.
What do fungiform papillae detect?
Different taste sensations.
Where are circumvallate papillae located?
At the back of the tongue near the throat.
Form a V shape. Usually about 7 circumvallate papillae
What do taste buds contain?
Receptors for the sense of taste.
What does Type I taste receptor detect?
Low salt
What does Type II taste receptor detect?
High salt, sweet, bitter, and kokumi
What does Type III taste receptor detect?
Acids
What does sodium influx lead to in taste transduction?
Opening of voltage gated calcium channels.
What does Chorda Tympani Nerve conduct signals from?
Conducts signals from the front and sides of the tongue.
From the fungiform papillae in particular
7th of 12th cranial nerve
What does Glossopharyngeal Nerve conduct signals from?
The back 1/3 of the tongue.
corresponds with the circumvallate papillae
9th of 12 cranial nerves
What does Vagus Nerve conduct signals from?
Taste receptors in the mouth and larynx.
larynx and epiglottis
10th of 12 cranial nerve
What is the gustatory system responsible for?
The perception of taste.
Percieved through brain areas such as the insula (primary cortex) and the OFC (secondarey cortex)
Where do taste signals arrive first in the brain?
Nucleus tractus solitarius (NTS)
Brain Stem
What is the role of the thalamus in taste processing?
Relay station for sensory information.
What integrates taste with other sensory information?
Orbitofrontal cortex
What is the labelled line hypothesis?
Individual taste receptor cells encode a single taste quality.
1 TRC links to one taste fibre
What is the combinatory model in taste perception?
Transmitted by multiple fibres which encodes the taste quality.
What is a predominant taste for sucrose?
Sweet
What is a common taste quality for sodium nitrate?
Salty, sour, and bitter.
What does multi voxel pattern analysis examine?
Patterns in neural responses to different tastes.
Is taste quality represented topographically in the brain?
No
What is ageusia?
Total loss of taste.
What is hypogeusia?
Reduced sensitivity to taste.
What is hypergeusia?
Increased sensitivity to taste.
What is dysgeusia?
Unpleasant sensitivities to taste.
How does taste sensitivity change as we age?
Generally declines.
What genetic factor influences taste perception?
Gene expression of TAS2R38.
Taste receptor 2, member 38
What is a universal preference in taste perception?
Sweet and salty perceived as good, sour and bitter perceived as bad.
What is the first step in the order of taste perception to the brain?
The first step is the activation of taste buds on the tongue.
True or False: Taste signals are transmitted directly to the brain’s visual cortex.
False
Fill in the blank: The taste signals are processed in the __________ before being sent to the brain.
thalamus
Which cranial nerves are primarily involved in taste perception?
The facial nerve (VII), glossopharyngeal nerve (IX), and vagus nerve (X).
What is the final destination of taste signals in the brain?
The primary gustatory cortex.
Order from taste to brain
tongue, papillae, taste buds, taste receptors, depolarisation of taste cell, signal activation, brainstem (NST), thalamus, primary cortex (insula), Secondary cortex (orbitofrontal cortex),
Ageusia
Total loss of taste
Hypoageusia
decreased taste sensitivity
hyperageusia
increased taste sensitivity
dysgeusia
unpleasant taste sensitivities
