Sense of Taste

Question 2

What is/are the organ(s) of taste?

Answer 2

The taste buds are the receptor organs for taste

Question 3

Where are taste buds located?

Answer 3

Most of the 10,000+ tste buds are found on the tongue in papillae (raised bumps)

-additional taste buds are sparsely distributed in the cheeks, soft palate, pharynx & epiglottis

Question 4

how are taste buds shaped?

Answer 4

Taste buds are flask shaped

Question 5

What are the three major cells types consisting in taste buds?

Answer 5

Basal cells

Gustatory cells

Supporting cells

Question 6

Describe basal cells within taste buds

Answer 6

dynamic stem cells (replace gastatory cells every 7-10 days)

Question 7

Describe gustatory cells within taste buds

Answer 7

Taste cells with gustatory hair that project into a taste pore

Question 8

Describe supporting cells within a taste bud

Answer 8

Supporting cells within taste buds inculate the receptor

Question 9

What are the five basic taste sensations?

Answer 9

• sweet
• salt
• sour
• bitter
• umami (savory)

Question 10

What do sweet sensations respond to?

Answer 10

sweet - responds to sugars, saccharin, alcohol and some amino acids

Question 11

What do salt sensations respond to?

Answer 11

salt - response to metal ions

Question 12

What do sour sensations respond to?

Answer 12

sour - responds to hydrogen ions

Question 13

What do bitter sensations respond to?

Answer 13

bitter - responds to alkaloids such asn quinine and nicotine (alerts us to poisons)

Question 14

What do amami (savory taste) respond to?

Answer 14

Umami (savory taste) is elicited by amino acid glutamate

-

Question 15

how is amino acid glutamate produced?

Answer 15

by meats, meat broths, cheese (typically animal-based protein-rich foods)

Question 16

What must happen to a chemical in order for taste to occur?

Answer 16

A chemical must be dissolved in saliva & must contact gustatory hairs

Question 17

What happens when a food chemical is bound to a gustatory hair?

Answer 17

it depolarizes the membrane

Then a neurotransmitter is released which initiates a graded potential that elicits an AO

Question 18

Describe what happens when salt is bound

Answer 18

Direct Na+ influx causes depolarization

Question 19

Describe what happes when sour is bound

Answer 19

H+ ions directly open cation channels

Question 20

Which tasts involve a 2nd messenger system?

Answer 20

sweet, bitter, and umami

Question 21

Gustatory Pathway: on what route do CNVII and IX carry impulses?

Answer 21

CN VII and IX carry impulses from the tongue taste buds to the solitary nucleus of the medulla

Question 22

Gustatory Pathway: on what route do CN X carry impulses?

Answer 22

CN X carries impulses from the cheek, phyarynx and epilglottis to the solitary nucleus of the medulla

Question 23

After impulses reach the solitary nucleus of the medulla, where to they travel to?

Answer 23

To the thalamus, they then branch to:

• Gustatory cortex in the insula
• hypothalamus and limbic system (appreciation of taste and associated emotions)

Question 24

What consitutes 80% of the taste experience?

Answer 24

smell

Question 25

how does age affect smell?

Answer 25

The age-related decline in sense of smell often leads to increased consumption of sweets and salty foods:

loss of appetite and nutritional deficits

Question 26

what other receptors affect taste?

Answer 26

thermoreceptors, mechanoreceptors, nociceptors can enhance or detract from taste

Ex: Capsaicin-laden foods override the ability to distinguish “taste”