week 10 - taste

Question 1

papillae

Answer 1

• extensions of the skin
• help increase surface area of the tongue

Question 2

Where does transduction occur in the taste system?

Answer 2

when chemicals contact the receptor sites on the tips of taste buds

Question 3

Why is the taste system considered the gatekeeper of the body?

Answer 3

• identify things that should be consumed for survival
• detect and reject harmful things
• cause good/bad affective responses

Question 4

What is the taste cell pathway in cranial nerve 7?

Answer 4

takes information from chorda tympani (cn 7) from the front and sides of tongue to brain

Question 5

What is the taste cell pathway in cranial nerve 9?

Answer 5

takes information from glossopharyngeal nerve (cn 9) from back of tongue

Question 6

What is the taste cell pathway in cranial nerve 10?

Answer 6

takes information from vagus nerve (cn 10) from mouth and throat

Question 7

What is the pathway information from cranial nerves to the process of coding?

Answer 7

these pathways make connections in the nucleus of the solitary tract in the spinal cord -> thalamus -> insula -> frontal lobe and frontal perculum

Question 8

What makes the taste system different from other sensory systems we have learned about?

Answer 8

• no time for information to cross over to the side of brain
• ipsilateral (right side of tongue gets processed by right insula)

Question 9

t/f: primary tastes are associated with the same receptors

Answer 9

false, they each have their own different type of receptors

Question 10

monosodium glutamate (MSG)

Answer 10

• genetically based
• flavor enhancer

Question 11

Water taste receptor experiment

Answer 11

• researchers found sour taste receptors in rats and inhibited them
• resulted in an inability to differentiate water from other substances

Question 12

What is an example of different chemicals exciting different receptors?

Answer 12

Miracle berries activate sweet receptors in an inappropriate way which causes receptors to respond to any chemicals coming into the mouth

Question 13

What primary taste receptors are ionotropic?

Answer 13

salty and sour

Question 14

Salty taste receptors

Answer 14

• excited by Na+
• permits Na+ to cross membrane

Question 15

Sour taste receptors

Answer 15

• activated by acids
• closes K+ channels

Question 16

What primary taste receptors are metabotropic?

Answer 16

sweet, bitter, and umami

Question 17

What is the process of metabotropic taste receptors?

Answer 17

• require a messenger inside of taste receptors as their transduction pathway of effects
• molecule binds to receptor -> g-protein interacts with 2nd messenger

Question 18

distributed coding

Answer 18

pattern of distribution in which all neurons fire at different rates

Question 19

Erikson experiment pt. 1 (distributed coding)

Answer 19

• measured action potentials in a specific nerve of the chorda tympani while presenting different taste stimuli to rats
• brain activity was similar for 2 substances but completely different for one which suggests they taste similar

Question 20

Erikson experiment pt. 2 (classical conditioning)

Answer 20

• shocked rat when they drank a specific substance
• when presented with similar tasting substance, rat stayed away
• continued to drink substance that tasted different

Question 21

How was distributed coding showcased in Erickson’s experiment?

Answer 21

through both physiological responses with chorda tympani fibers firing as well as behavioral responses

Question 22

specificity coding

Answer 22

specific receptors coded for a specific taste

Question 23

Mueller experiment (PTC)

Answer 23

gave mice a PTC gene (not found in mice) and measured the amount of licks when presenting a PTC concentration

Question 24

What were the results of the Mueller experiment?

Answer 24

number of licks decreased

Question 25

Mueller experiment (Cyx)

Answer 25

- took out Cyx receptor gene which is a substance mice usually avoid - mice did not avoid cyx after is was removed

Question 26

Sato experiment (monkey's chorda tympani)

Answer 26

- recorded nerve fibers in monkey's chorda tympani - results showed that some fibers repsonded best to one of the basic tastes but poorly to the others

Question 27

How are the taste system and the visual system for color similar?

Answer 27

different parts of pathway contribute to coding

Question 28

What might cause differences in tasting?

Answer 28

- genetic basis - distribution of taste receptors - supertasters (more fungiform paillae -> stronger taste sensitivity - hormones