Chapter 15 (M. Wolfe)

Question 1

3. What happens when the chorda tympani is anesthetized?

Answer 1

When the chorda tympani is anesthetized, one cannot taste anything. This cranial nerve normally carries information from taste receptors to the brain

Question 2

What are taste buds?

Answer 2

Taste buds are globular clusters of cells that create the neural signals conveyed to the brain by taste nerves. Some of the cells in the taste bud have specialized sites on their apical projections that interact with taste stimuli. Some of the cells form synapses with taste nerve fibers.

Question 3

What is the function of the taste receptor cells?

Answer 3

Taste receptor cells within the taste bud contain sites on their apical projections that interact with taste stimuli. These sites fall into two major categories: those interacting with charged particles, and those interacting with specific structures.

Question 4

How do the microvilli help in the process of taste perception?

Answer 4

The microvilli are slender projections on the tips of some taste bud cells that extend into the taste pore. They contain sites that bind taste substances and help in the process of taste perception

Question 5

What causes something to taste sour?

Answer 5

Acidic solutions—those having a relatively higher proportion of hydrogen ions—taste sour to us.

Question 6

How is sensitivity for bitter flavors different for women than for men?

Answer 6

Sensitivity for bitter flavors is affected by hormone levels in women; this is not the case for men.

Question 7

What is cross-modality matching?

Answer 7

It is the ability to match the intensities of sensations that come from different sensory modalities. For instance, adjusting a light until it is as bright as a lemon tastes sour would be a cross-modality matching task.

Question 8

Describe the labeled lines theory.

Answer 8

The labeled lines theory states that each nerve fiber carries a particular taste quality. For example, the quality evoked from a sucrose-best fiber is sweet, that from NaCl-best fiber is salty, and so on

Question 9

One example of cross-adaptation in taste perception

Answer 9

After eating something sweet, and immediately after consuming a sour beverage such as lemonade. The lemonade tastes a lot more sour than it normally does. This is due to the sugar in the candy causing the sweet receptors to adapt.

Question 10

Basic taste

Answer 10

Any of the four taste qualities that are generally agreed to describe human taste experience: sweet, salty, sour, bitter.

Question 11

Chorda tympani

Answer 11

The branch of cranial nerve VII (the facial nerve) that carries taste information from the anterior, mobile tongue (the part that can be stuck out)

Question 12

Cranial nerves

Answer 12

Twelve pairs of nerves (one for each side of the body) that originate in the brain stem and reach sense organs and muscles through openings in the skull

Question 13

Flavor

Answer 13

The combination of true taste (sweet, salty, sour, bitter) and retronasal olfaction

Question 14

Insular cortex

Answer 14

The primary cortical processing area for taste—the part of the cortex that first receives taste information

Question 15

Labeled lines

Answer 15

A theory of sensory coding in which each nerve fiber carries a particular stimulus quality.

Question 16

Microvilli

Answer 16

Slender projections of the cell membrane on the tips of some taste bud cells that extend into the taste pore

Question 17

Nontaster (of PTC/PROP)

Answer 17

An individual born with two recessive alleles for the TAS2R38 gene and unable to taste the compounds phenylthiocarbamide and propylthiouracil.

Question 18

Papilla

Answer 18

Any of multiple structures that give the tongue its bumpy appearance. Types include fungiform, foliate, circumvallate, and filiform.

Question 19

Specific hungers theory

Answer 19

The idea that deficiency of a given nutrient produces craving for that nutrient.

Question 20

Tastant

Answer 20

Any stimulus that can be tasted.

Question 21

Taste receptor cell

Answer 21

A cell within the taste bud that contains sites on its apical projection that can interact with taste stimuli.

Question 22

Taste

Answer 22

Sensations evoked by solutions in the mouth that contact receptors on the tongue and the roof of the mouth that then connect to axons in cranial nerves VII, IX, and X.