Final: Chapter 16 Flashcards
What 3 components do chemical senses involve?
taste, olfaction, flavor
Occurs when molecules - often associated with food - enter the mouth in solids or liquid form and stimulate receptors on the tongue
Taste
Occurs when airborne molecules enter the nose and stimulate receptor neurons in the olfactory mucosa, located on the roof of the nasal cavity
Olfaction
The impression we experience from the combination of taste and olfaction
Flavor
Light stimulates rod and cone receptors inside the eyeball
Vision
Pressure changes are transmitted to hair cells located deep inside the cochlea
Hearing
Stimuli applied to the skin are transmitted to receptors or nerve endings hidden under the skin
Cutaneous senses (touch)
Molecules stimulate receptors that are exposed to the environment
Taste and olfaction
The constant renewal of the receptors
Neurogenesis
occurs when molecules enter the mouth in solid or liquid form and stimulate taste receptors on the tongue
Taste
What are the 5 basic taste sensations?
salty, sour, sweet, bitter, and umami
Often associated with compounds that have nutritive or caloric value and that are, therefore, important for sustaining life.
Sweetness
Compounds cause an automatic acceptance response and also trigger anticipatory metabolic responses that prepare the gastrointestinal system for processing these substances
Sweet compounds
Triggers automatic rejection responses to help the organism avoid harmful substances
Bitter compounds
Often indicates the presence of sodium
Salty tastes
Why do people seek salty foods?
to replenish the salt their body needs, especially if they lose a lot of sodium through sodium
The structures that cause the ridges and valleys that are located on the surface of the tongue
Papillae
What are the 4 categories of papillae?
- filiform papillae
- fungiform papillae
- foliate papillae
- circumvallate papillae
shaped like cones and are found over the entire surface of the tongue, giving it its rough appearance
Filiform papillae
shaped like mushrooms and found at the tip and sides of the tongue
Fungiform papillae
Are a series of folds along the back of the tongue on the sides
Foliate papillae
Are shaped like flat mounds surrounded by a trench and are found at the back of the tongue
Circumvallate papillae
All of the papillae except the filiform papillae contain ______________.
taste buds
How many taste cells does each taste bud contain?
50 to 100 taste cells
Have tips that protrude into the taste pore
Taste cells
Occurs when chemicals contact receptor sites located on the tips of these taste cells
Transduction
List the 4 ways that electrical signals generated in the taste cells are transmitted from the tongue toward the brain in a number of different nerves
- the chorda tympani nerve (from taste cells on the front and sides of the tongue)
- the glossopharyngeal nerve (from the back of the tongue)
- the vagus nerve (from the mouth and throat)
- the superficial petrosal nerve (from the soft palette - the top of the mouth)
From this area, signals travel to the thalamus and then to two areas in the frontal lobe that are considered to be the primary taste cortex - the insula and the frontal operculum - which are partially hidden behind the temporal lobe
Nucleus of the solitary tract
The receptor sheet for taste. It contains papillae and all of the other structures like taste buds, taste cells, etc.
Tongue
The structures that give the tongue its rough appearance. There are 4 kinds, each with a different shape.
Papillae
Contained on the papillae. There are about 10,000 taste buds
Taste buds
Cells that make up a taste bud. There are a number of cells for each bud, and the tip of each one sticks out into a taste pore. One or more nerve fibers are associated with each cells.
Taste cells
Sites located on the tips of the taste cells. There are different types of sites for different chemicals, Chemicals contacting the sites cause transduction by affecting ion flow across the membrane of the taste cell
Receptor sites
The idea that quality is signaled by the activity in individual neurons that are tuned to respond to specific qualities
Specificity Coding
The idea that quality to signaled by the pattern of activity distributed across many neurons
Population Coding
Another name for population coding
Across-fiber patterns
What is evidence for the specificity coding?
That there are receptors that are specifically tuned to sweet, bitter, and umami tastes
Blocks the flow of sodium into taste receptors
Amiloride
What happens when you apply amiloride to the tongue?
It causes a decrease in the responding of neurons in the rat’s brainstorm (nucleus of the solitary tract) that respond best to salt.
How are neurons tuned in the taste system?
Broadly tuned, with many neurons responding to more than one taste quality
Involved in determining taste as well, especially at higher levels of the system
population coding
What could determine subtle differences between tastes within a category?
population coding
Can genetic differences affect people’s ability to sense the taste of certain substances?
YES
Bitter substance that some people have the ability to taste
Phenylthiocarbamide (PTC)
What is another substance experimented with that has properties similar to PTC?
PROP (6-n-propylthiouracil)
What causes the differences in people’s ability to taste PROP?
People who can taste PROP have higher densities of taste buds than those who can’t taste it
having a poor sense of smell that is not crucial to survival
Microsmatic
Having a well developed sense of smell
Macrosmatic
The lowest concentration at which an odorant can be detected.
Detection threshold
Participants are presented with blocks of two trials - one trial contains a weak odorant and the other, no odorant
Forced-choice method
TRUE OR FALSE: knowing the correct label for the odor seems to not affect our perception into that odor
FALSE, labels transforms our perceptions of odor
Cells that provide metabolic and structural support to the olfactory sensory neurons
Sustentacular cells
What cognitive disease is loss of smell associated with?
Alzheimer’s disease (AD)
What is the main difference of olfactory losses between AD and COVID-19?
In AD, the loss of olfaction begins occurring decades before the occurrence of clinical symptoms such as memory loss and difficulties in reasoning.
What can we do with other senses that we cannot do with olfaction?
We can describe other senses, like colors relating to wavelengths for vision or describing different pitches for sound, but we lack the specific language for odor quality.
Can molecules that have similar structures smell different?
YES
Can molecules that have different structures smell similar?
YES
There are odorants that did not exist in nature and have a quality that no human has smelled before, and which cannot be explained by reference to other odorants.
Odor objects
What is the first stage of perceiving odor objects?
Takes place in the olfactory mucosa and olfactory bulb, involves analyzing. The olfactory system analyzes the different chemical components of odors and transforms these components into neural activity at specific places in the olfactory bulb
What is the second stage of perceiving odor objects?
Takes place in the olfactory cortex and beyond, involves synthesizing. The olfactory system synthesizes the information about chemical components received from the olfactory bulb into representations of odor objects
A dime-sized region located on the roof of the nasal cavity just below the olfactory bulb
Olfactory mucosa
What is carried into the nose in the air stream, which brings these molecules into contact with the mucosa?
Odorant molecules
Located in the mucosa and the supporting cells
Olfactory receptor neurons (ORNs)
Are sensitive to chemical odorants
Olfactory receptors
What is one parallel between visual pigments and olfactory receptors?
They are both sensitive to a specific range of stimuli.
Measures the increase in calcium ions by soaking olfactory neurons in a chemical that causes the ORN to fluoresce with a green glow when exposed to ultraviolet (380nm) light
Calcium imaging
When the olfactory receptors responds, the concentration of ______________ increases inside the OR.
Calcium ions (Ca++)
The pattern of activation for each odorant, which is indicated by reading across each row
Oderant’s recognition profile
Activation of receptors in the mucosa causes electrical signals in the ORNs that are distributed across the mucosa. These ORNs send signals to structures called?
Glomeruli
What is the basic principle of the relationship between ORNs and glomeruli?
All of the ORNs of a particular type send their signals to just one or two glomeruli, so each glomerulus collects information about the firing of a particular type of ORN.
functional organization of glomerular activity patterns
Chemotopic maps
a representation of how chemical structures are perceived as odors
Odor maps
to enhance both the detection and discrimination of odorants
Odotoptic maps
What led to the proposal of odotopic maps?
DIfferent chemicals cause activity in specific areas
Odorants that caused activity in specific locations in the olfactory bulbs now cause widespread activity in the __________, and there is now an overlap between the activity caused by different odorants.
Piriform cortex (PC)
Similar to fMRI, which determines brain activation by measuring changes in blood flow, it shows that hexanal and pentyl acetate cause different patterns of activity in the rat olfactory bulb.
Functional ultrasound imagery
What does the formation of odor objects involve?
Learning, which links together the scattered activations that occur for a particular object
What happens to neurons when they are exposed to the same smell stimuli over and over again?
Neural connections form, and the neurons become associated with eachother.
When does a stable memory become established?
When neurons become linked
When do odor objects become formed?
When experience with an odor causes neurons in the piriform cortex to become linked
Can olfaction create memories?
yes under some circumstances
dramatic description of how tasting a cookie unlocked memories he hasn’t thought of for years
Proust effect
What are some characteristics of the Proust effect?
- memories were realized not by seeing the cookie but by tasting it
- memory was vivid and transported Proust back to a number of places from his past
- the memory was from Proust’s early childhood.
Elicited by odors and are memories about events from a person’s life story
Evoked autobiographical memories (OEAMs)
overall impression that we experience from the combination of nasal and oral stimulation
Flavor
Sensations we experience from both olfactory and taste receptors are referred to the mouth
Oral capture
Neurons that respond to more than one sense
Bimodal neurons
Odor associated with the food eaten to satiety (the quality or state of being fed or gratified to or beyond capacity)
Sensory-specific satiety
a nexus for sensory integration, the modulation of autonomic reactions, and participation in learning, prediction and decision making for emotional and reward-related behaviours.
Orbitofrontal cortex
Activity is related to the pleasantness of an odor or flavor/ involved in determining the reward value of foods
Orbitofrontal cortex
Interactions that involve more than one sense of quality
Multimodal interactions
a perceptual illusion that demonstrates how the brain combines visual and auditory information to create a unified understanding of speech; seeing a speaker’s lips move can affect what sound the listener hears
McGurk Effect
refers to how a property of a chemical sense - taste, olfaction, or flavor - is associated with properties of other senses.
Correspondences
According to correspondences, fruits were matched with _________.
High pitches
According to correspondences, smells such as musk and dark chocolate were matched with _________.
low pitches
According to correspondences, tastes of citric acid and sucrose were matched with _________.
high tones
According to correspondences, tastes of coffee and MSG were matched with _________.
lower tones
How old are infants that respond to banana extract or vanilla extract with sucking and facial expressions that are similar to smiles, and respond to concentrated shrimp odor and an order resembling rotten eggs with rejection or disgust?
3 to 7 days old
How does a mother’s diet during pregnancy affect the developing fetus?
it changes the flavor profile of the amniotic fluid; by the last trimester, the taste and olfactory receptors are functioning and the fetus swallows between 500 to 1000 ml of amniotic fluid a day
