Chapter 4 - The Chemosensory System: Taste and Smell

Question 1

olfactory system

Answer 1

chemosensory system that deals with the detection of ariborn chemicals and which produces the perceptual impressions of smell

Question 2

gustatory system

Answer 2

chemosensory system that deals with the detection of dissolved chemicals and that produces the perceptual impression of taste

Question 3

pheromones

Answer 3

chemical substance emitted by specialized glands in many animals to attract mates, singal sexual receptivity, or affect the behaviour of othe memebers of the same species

Question 4

vomeronasal organ (VNO)

Answer 4

paired chemosensory organ located in the nasal cavities of many terrestrial species. Also known as Jacobson’s organ, the VNO appears to be the primary sensory system for the detection of pheromones

Question 5

umami

Answer 5

taste common to diverse foods such as fish, meats, cheese, and some vegetables. Corresponding words in English are savoury, brothy, and meaty

Question 6

taste buds

Answer 6

specialized pear-shaped sensory structure found primarily in the skin of the tongue. Taste buds contain the cells that are responsible for genrating taste signals in response to chemicals dissovled in the saliva

Question 7

papilla (include types)

Answer 7

small mounds of tissue found of the surface of the tongue. The term is derived from the Latin word for the niple of the mammary gland. . Includes: Filiform, fungiform, foliate, circumvallate

Question 8

tastants

Answer 8

chemical stimuli derived from foods that are dissolved in saliva and which produce electrical signals in taste buds

Question 9

microvilli

Answer 9

small folds in the membrane of receptor cells where testant binding occurs

Question 10

facial, glossopharyngeal, and vagus nerves

Answer 10

cranial nerves VII, IX, and X, respectively. These nerves, expecially VII and IX, carry gustatory signals to the brain

Question 11

second messenger

Answer 11

specific chemical substance that is involved in the transduction cascade within cells

Question 12

labelled-line coding

Answer 12

notion that sensory neurons are selective to only a specific type of stimulus. In the gustatory system, this hypothesis asserts that taste neurons are selective to only one of the taste primaries

Question 13

cross-fibre coding

Answer 13

notion that sensory neurons are triggered by a broad range of stimuli. In the gustatory system, this hypothesis asserts that taste neurons can be stimulated by multiple taste primaries

Question 14

chemotopic organization

Answer 14

organized representation of different taste primaries in the gustatory system

Question 15

nucleus of the solitary tract (NST)

Answer 15

collection of neurons locted in the medulla of the brain sttem. A subset of the neurons here seves to relay taste signals to the thalamus

Question 16

ventral posterior medial nucleus (VPMN)

Answer 16

small nucleus in the thalamus that serves as the second relay for taste signals. Neurons here send their axons to the primary gustatory cortex

Question 17

insula

Answer 17

area of the cerebral cortex in the frontal lobe that is located within the Sylvian fissure. the insula are surrounding cortex together make up the primary gustatory cortex

Question 18

glomerulus

Answer 18

confined spatial unit in the olfactory bulb where several thousand axons from olfactory sensory neurons converge. Each glomerulus is believed to act as a small functional module for processing olfactory information

Question 19

concentration

Answer 19

a measure of the amount of dissolved substance per unit volume of a solution

Question 20

electrogustometry

Answer 20

application of electrical current to the tongue through an electrode to determine taste function

Question 21

chemogustometry

Answer 21

application of chemical solutions to the tongue to determine taste functions

Question 22

hedonic

Answer 22

judgment of sensory quality in terms of positive or negative appreciation (like or dislike)

Question 23

dysgeusia

Answer 23

distortion of taste sensation

Question 24

adaptation

Answer 24

reduction in perceived intensity or sensitivity due to prior or ongoing background stimulation

Question 25

cross-adaptation

Answer 25

reduction in perceived intensity or sensitivity to a compound due to the adaptation to a different one

Question 26

flavour

Answer 26

combination of sensory influences such as taste, smell, touch, and vision that together produce a complex perceptual impression during eating

Question 27

capsaicin

Answer 27

active ingredient in chili peppers, which causes the hot burning sensation

Question 28

primary olfactory cortex

Answer 28

general name given to the five brain areas that receive a direct projection from the olfactory bulb - anterior olfactory nucleus, olfactory tubercle, amygdala, piriform cortex, and entorhinal cortex

Question 29

limbic system

Answer 29

region of the brain concerned with motivation, emotion, and certain kinds of memory

Question 30

isomerism

Answer 30

difference in the spatial arrangement of atoms in an otherwise identical chemical compound

Question 31

criterion effects

Answer 31

pre-existing bias for a particular sensory quality that can affect recognition threshold measures. A discussion of this parameter was presented in Chapter 1