Chapter 16

Question 1

gustation

Answer 1

taste

Question 2

olfaction

Answer 2

smell

Question 3

how are taste and smell “gatekeepers” of the body

Answer 3

identify things to survive or reject

create good and bad emotional responses

Question 4

how long do taste and olfactory receptors live and die

Answer 4

taste: 1-2 weeks

smell: 5-7 weeks

Question 5

5 basic taste sensations

Answer 5

salty (sodium chloride)

sour (hydrochloric acid)

sweet (sucrose)

bitter (quinine)

umami (meaty, brothy, savory, MSG)

Question 6

function of taste

Answer 6

determine which substances to consume and avoid

sweetness (often offers nutritive value)

bitter (potentially harmful)

salty (crave salty foods if body is depleted from sweating)

Question 7

papillae

Answer 7

ridges and valleys in the tongue

filiform (shaped like cones; entire tongue)

fungiform (mushrooms; tip and sides)

foliate (folds; back of sides of tongue)

circumvilliate (flat mounds; back of tongue)

Question 8

taste buds

Answer 8

located in all papillae except for filiform

whole tongue has 10,000

each taste buds has 50-100 taste cells (identify different types of chemicals for taste)

Question 9

transduction of tase

Answer 9

chemicals from receptor sites in tip of the taste cells turn into electrical signals for the brain to interpret taste

electrical signals sent to different nerves:
chorda tympani (from front and sides of tongue)
glossopharyngeal (from back of tongue)
vagus (from mouth and throat)
superficial petronasal (from soft palette located in top of mouth in the back)

Question 10

where do electrical signals from the tongue, mouth, and throat travel through to the brain

Answer 10

nucleus of solitary tract (brain stem) and onto thalamus

then signals travel to primary taste cortex in frontal lobe (insula and frontal operculum cortex)

Question 11

population coding

Answer 11

neurons that detect a combination of taste (generalized)

aka across fiber patterns

rats cannot distinguish certain taste over others (neurons fire for similar chemicals)

Question 12

specificity coding

Answer 12

neurons detect a specific type of taste

PTC and PROP (chemical found in humans for detecting bitterness)

Question 13

experiments on PTC and PROP

Answer 13

tasters (have more taste buds)

nontasters (lack of taste buds for bitterness)

super tasters (more sensitive than tasters for bitterness)

Question 14

function of olfaction

Answer 14

important for survival

helps us to be aware of dangerous smells

Question 15

macrosmatic smell

Answer 15

heavily reliant on smell

for animals, keen sense of smell is necessary for survival

provides cues for location and food

Question 16

microsmatic smell

Answer 16

for humans, less keen sense of smell

not crucial to survive

Question 17

pheromones

Answer 17

odor molecules emitted by member of species, causing a specific reaction to another individual of the same species

Question 18

research on pheromones

Answer 18

men rate women’s shirts more pleasant when they are on their menstrual cycle

men had higher testosterone levels when smelling shirts of woman who were ovulating

Question 19

isolated congenital anosmia (ICA)

Answer 19

people who were born without sense of smell

report feeling more socially insecure

Question 20

anosmia

Answer 20

inability to smell due to injury or infection

problematic for detecting taste because smell and taste are well connected

Question 21

how many different odors can humans discriminate

Answer 21

a trillion

Question 22

difference between identifying and naming odors

Answer 22

identifying (knowing that odor has certain smell but cannot label exact smell)

naming (being able to label the smell can transform our perception into identifying that odor)

Question 23

two stages of perceiving odor

Answer 23

first stage (analyzing odor, transduction of odor)

second stage (synthesizing odor; putting together and organizing odor info to perceive smell)

Question 24

olfactory mucosa

Answer 24

dime sized region at top of inside of nasal opening but below olfactory bulb

contains olfactory receptor neurons (ORN), important for odor chemicals to be carried as electrical signals to brain

ORN have olfactory receptors (area of neuron that receives odor molecules)

10,000 ORNs for each one of the 400 types of olfactory receptors

ORN carries odor chemicals, received by olfactory receptors in olfactory mucosa

Question 25

glomeruli

Answer 25

responsible for collecting info about ORN’s electrical signals that would then be processed in the brain

in olfactory bulb

each type of olfactory receptors sent to one or two of these glomeruli

Question 26

olfactory process

Answer 26

olfactory mucosa (ORN and olfactory receptors) -> olfactory bulb (glomeruli) -> piriform cortex, orbitofrontal cortex, amygdala

Question 27

where do neurons fire from olfactory bulb

Answer 27

piriform cortex (primary olfactory area; perceived odors; located in temporal lobe area)

orbitofrontal cortex (secondary olfactory area; perceives odors; in frontal lobe)

amygdala (involved with emotion associated to smell and other senses)

Question 28

odor objects

Answer 28

where smell is coming from

forming representations involves learning and memory (repeated exposure creates link)

Question 29

flavor

Answer 29

ability to experience and identify foods and drinks consumed comes from both mouth and nose

flavor involved in retronasal route (from mouth to nasal pharynx – passage to nose)

chemical molecules still reaching olfactory mucosa as foods and drinks consumed in mouth to help identify flavors

in orbitofrontal cortex (from primary gustatory cortex)

Question 30

oral capture

Answer 30

sensations we experience from both olfactory and taste receptors are seen as only coming from mouth

Question 31

two influences of flavor

Answer 31

expectation

sensory specific satiety

Question 32

Proust effect

Answer 32

ability to remember events based on taste and smell senses because of amygdala and hippocampus