Chapter 15 Flashcards Preview

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Flashcards in Chapter 15 Deck (56):
1

taste

when molecules stimulate taste receptors on tongue

2

5 taste qualities

sweet

sour

salty

bitter

umami

3

papillae

the structures that make up all the ridges and valleys of the tongue

4

four categories of papillae

filiform - cones; all over tongue

fungiform - mushroom shaped; tip and sides

foliate - folds on the back and sides

circumvilliate - flat mounds surrounded by trenches; back of tongue

5

which papillae contain taste buds

all except the filiform

6

about how many taste buds are on the entire tongue

10,000

7

what happens when you stimulate the middle part of the tongue and why

no taste - contain only filiform papillae that have no taste buds

8

taste cells

on taste buds in groups of 50-100

have tips that protrude into taste pore

9

taste transduction

chemicals contact receptor sites on the tips of the taste cells

10

4 nerves that transmit electrical signals from the tongue

chorda tympani nerve (front and sides of tongue)

glossopharyngeal (back)

vagus nerve (mouth and throat)

superficial petronasal nerve (from soft palette)

11

nucleus of the solitary tract

where nerve fibers from the tongue, mouth and throat make connections to the brain

12

where do fibers go after the nucleus of the solitary tract

thalamus 

taste cortex - insula and frontal operculum cortex

13

Evidence for distributed coding in taste

rat experiment that found across-fiber patterns for similar chemicals

applied to humans

14

Evidence for taste specificity coding

cloning experiments - PTC receptors

taste receptor eliminated - no substance avoidance

 

some taste neurons found that respond specifically, some to a range of things

15

amiloride

a substance that blocks the flow of sodium into taste receptors

decrease response in salt receptors

16

What may cause individual differences in tasting? 

genetic differences that affect the presence of receptors that respond to different chemicals

 

same goes for smell

17

macrosmatic

having keen sense of smell important for survival

18

microsmatic

less keen sense of smell

not crucial for survival

 

humans

19

pheromones

molecules emitted by members of a species that causes a specific reaction in another animal

20

anosmia

loss of the ability to smell bc of injury/infection

21

detection threshold

the lowest concentration at which an odorant can be detected

22

Why are humans less sensitive to odors than dogs even though they can have similar detection thresholds?

humans have way less receptors than dogs

23

recognition threshold

 

how does this usually compare to the difference threshold

the concentration at which quality can be recognized

 

has to be increased at least 3x as much

24

what makes smell recognition harder?

not being able to pull the lable from our memory

25

What makes relating odors to physical properties so difficult

-language of odor quality

-molecules with similar structures can smell different/vise versa

-we constantly encounter mixtures of molecules

26

odor objects

sources of odors we can identify

coffee, bacon, etc.

27

2 stages of perceiving odor objects

analyzing

synthesizing

28

analyzing stage of odor perception

occurrs in olfactory mucosa and olfactory bulb

olfactory system analyzes different chemical components of odors and transforms them into neural activity at specific places in olfactory bulb

29

synthesis stage of odor perception

occurs in olfactory cortex

olfactory system synthesizes info about chemicals into representations of odor objects

involves learning and memory

30

olfactory mucosa

small region on roof of nasal cavity

just below olfactory bulb

contains smell receptors

31

olfactory bulb

receives signals directly from olfactory receptors

glomeruli

32

olfactory receptor neurons (ORNs)

in mucosa and its supporting cells

33

olfactory receptors

molecules that dot the receptor neurons in the mucosa that are sensitive to oderants

34

one parallel between visual pigment receptors and olfactory receptors

both sensitive to a specific range of stimuli

(specific band of wavelengths vs narrow range of oderants)

35

# of olfactory receptors

 

how many types per ORN

350 types

 

 

one

36

what is the firing pattern of ORNs for each oderant

each one causes a different pattern of firing

when odors smell different they usually have different recognition profiles

37

glomeruli

in olfactory bulb

receive signals from ORNs

38

relationship between ORNs and glomeruli

10,000 ORNs of 1 type send signals to 1 or 2 glomeruli

39

generally describe activation pattern of olfactory bulb

different oderants cause activation in different areas

40

chemotopic map

pattern of activation in olfactory system where chemicals create a map of activation based on their properties

41

2 main olfactory areas

primary and secondary

 

additional areas

primary: piriform cortex

secondary: orbitofrontal cortex

 

 

amygdala

42

how are oderants represented in the piriform cortex

activity is scattered over a large area

43

what does the formation of odor objects involved

learning activation and memory

44

describe the activation of smelling something for the first time

 

4 steps

chemicals activate receptors in the mucosa

then a pattern on olfactory bulb shaped by chemotopic map

scattered activation in piriform cortex

multiple exposures lead these to be linked

45

retronasal route

food and drink chemicals go along this path to the olfactory mucosa

from mouth to nasal pharynx

46

nasal pharynx

passage connecting oral and nasal cavities

47

oral capture

when sensations from both olfaction and taste are perceived as being located in the mouth

48

What other two senses contribute to flavor

 

How does this happen in the brain

vision and touch

 

signals sent to amygdala (vision), structures in taste pathway (touch), orbitofrontal cortex (vision and touch)

49

bimodal neurons

 

where are many found

neurons that respond to more than one sense

 

orbitofrontal cortex

50

important property of bimodal neurons

respond to similar qualities (taste of sweet fruits and the smell of them)

tuned to respond to qualities that occur together in the environment

51

what do the properties of bimodal neurons suggest about the orbitofrontal cortex

its a cortical center for detecting flavor and for perceptual representations of foods

52

along with OFC what other structure is involved in flavor perception

insula - primary taste cortex

53

2 ways flavor can be influenced

expectations

amount of particular food already consumed

54

how does satiety affect flavor experience

food is more pleasurable when youre hungry than satisfied

55

sensory-specific satiety

 

example

the perceptual effect of the smell associated with food eaten to satiety

ex: after eating bananas until satiety, pleasentness for vanilla decreased slightly but rating for banana became negative

56

how is the OFC related to sensory specific satiety

it is involved in determining the reward value of foods

 

food regulation