chemical senses

Question 1

uses of chemo senses

Answer 1

identify things that should be consumed for survival
detect things that could be harmful
causes good and bad emotional responses

Question 2

gustation

Answer 2

structure and function of taste

Question 3

4 types of papilla

Answer 3

filiform
funigofrm
foliate
circumvallate

Question 4

filiform papilla

Answer 4

shaped like cones
located over entire surface
no taste buds
only for structure

Question 5

fungiform papilla

Answer 5

shaped like mushrooms
found on sides and tip of tongue

Question 6

foliate papilla

Answer 6

series of fold on back and sides

Question 7

circumvallate

Answer 7

shaped like flat mounds in a trench
located at the back

Question 8

taste buds

Answer 8

tongue contains around 10,000
each has 50-100 tase receptor cells with tips that extend into the taste pore

transaction occurs when chemical contact the receptor sites on the tips of the taste cell
- sent to brain by an afferent axon

Question 9

areas of the tongue

Answer 9

tongue isn’t category specific

different areas don’t deter different tastes
all buds have same receptors on them
but some may have different sensitivities

Question 10

nerves in the tongue

Answer 10

3 different nerves pick up signals from different areas

vagus nerve - back of tongue
glossopharyngeal nerve - further back
facial nerve - tip of tongue

Question 11

neural pathway from tongue to cortex

Answer 11

signals from 3 nerves converge to solitary nucleus in brain stem
related to the thalamus

goes into primary gustatory cortex (insula)

signal passed to secondary gustatory cortex (frontal operculum)

pick up information from tongue
- different nerves from different areas
generates an action potential

Question 12

olfaction

Answer 12

structure and function of odour

Question 13

olfactory mucosa

Answer 13

membrane that contains the cilia of the olfactory receptors

where the receptors are found
pick up molecules from the air
where transduction occurs

Question 14

olfactory bulb

Answer 14

goes to olfactory bulb from mucosa

structure containing the neural circuits that process olfactory information

neurons recieven information directly from the axons of the olfactory receptors

Question 15

functions of olfaction

Answer 15

macrosmatic olfaction
- many animals
- keen sense of smell, necessary for survival

microsmatic olfaction
- present in humans
- less keen, not crucial

Question 16

detecting odours - sensitivity

Answer 16

different species have different sensitivities to odours
however individual receptors are all equally sensitive
- difference lies in number of receptors

Question 17

identifying odours - recognition

Answer 17

recognition threshold is the concentration needed to determine quality of an operant

humans can discriminate among many odours but cannot label them correctly
not caused by a lack of sensitivity

Question 18

puzzle of olfactory quality

Answer 18

difficult to map perceptual experience onto physical attributes

some molecules that have similar structures smell different
some molecules that have different structures smell the same

Question 19

neural pathways from nose to cortex

Answer 19

information from olfactory bulb passed to piriform cortex (primary olfactory cortex)

passed to orbitofrontal cortex (secondary)

all link to the amygdala
- related to emotions and fight or flight response

Question 20

flavour

Answer 20

combination of smell, taste and other sensations

odour stimuli from food in the mouth reach the olfactory mucosa through the retronasal route
- taste of many compounds influenced by olfaction

smell gives 80% of flavour
only 20% from gustation

Question 21

flavour effected by

Answer 21

smell
taste
context
appearance
texture
physiological state
temperature
mood state
beliefs - religion, diets, past experience

Question 22

2 pathways to brain in flavour

Answer 22

orthonasal
- not chewed, only in nasal cavity

retronasal
- molecules come into mouth and onto tongue
- nasal and oral cavity connected by nasal pharynx
- air flows through both absorbed by olfactory mucosa