Stimulation of Taste Buds; Plotting Taste; Effect of smell and Textures on Taste

Report by:Ria Marcelle T. Vivo

A. Stimulation of Taste BudsProcedure

Subject dries his/her tongue.

Experimenter then places some granulated sugar on the tip of the tongue; notes time. Mouth should not be closed.

Note: Time it takes to taste the sugar.

A. Stimulation of Taste BudsPrinciple Involved

Results:(+) not immediately tasting the sugar(-) Not tasting the sugar/immediately

tastes the sugarWhy?Taste receptors need a liquid medium in order for the tastants to bind to them

A. Stimulation of Taste BudsPrinciple Involved

What are tastants?• Tastant – chemical that stimulate

gustatory receptor cellsthese tastants are dissolved in saliva which acts as a solvent for taste substances; these diffuse to taste receptor sites.Salivary constituents can continuously stimulate the taste receptor – alteration of taste sensitivity

A. Stimulation of Taste BudsPrinciple Involved

Negative Results may be attributed to:Salivary amylase deficiency/overproductionNervous system damage, specifically:

Facial Nerve (VII)Glossopharyngeal Nerve (XI) and Vagus Nerve (X)Somatosensory and frontal cortex, Amygdala,

Hypothalamus, and Hippocampus*Three cranial nerves that contain axons of the first-order gustatory neurons that innervate taste buds

B. Plotting Taste Bud DistributionProcedure

Mouth should be rinsed thoroughly with water before each test, dry with paper towel.

Moisten swab generously with 5% sucrose solution; touch to the center, back tip, and sides of dorsal surfaces of tongue.

Mark with O on a tongue outline on the notebook, location of the sweet receptors as reported by subject.

Repeat with coffee powder to map bitter receptors (B symbol); NaCl for salty receptors (+ symbol); vinegar for sour receptors (- symbol)

Use fresh swab for each test, discard used swabs properly.

B. Plotting Taste Bud DistributionPrinciple Involved

Results:(+)

(-) Inability to taste/distorted sense of taste

B. Plotting Taste Bud DistributionPrinciple Involved

Negative results can be attributed to the ff.:Nervous system damageDisorders:Ageuisa – inability to taste sweet, sour,

bitter, or salty substancesHypogeusia – reduced ability to taste

(sweet, sour, bitter, or salty substances)Dysguesia – dysfunction/distortion of the

sense of taste

C. Effects of Smell and Texture on TasteProcedure

Ask subject to sit with eyes closed and pinch his/her nostrils shut.

Obtain samples of food items brought in class.

Subject should ever see the foods being used in

the test.

Use an out-of-sequence order of food testing. For each test, place a cube of food in the

subject’s mouth and ask him/her to identify the

food using the ff. activities:

A. Effect of Smell and Texture on TasteProcedure

(1)Manipulate food with tongue.

(2)Chew the food.

(3)If food not yet identified at this point,

ask the subject to release pinched nostrils and to continue chewing

to determine if a positive identification

can be made.

Record Results on the chart by checking the appropriate column.

Results:(+) Food recognition ability increases as the sequence progresses (-) Ability does not change or ability decreases as the

sequence progressesWhy?Flavor = taste + smellOlfactory and Gustatory – closely related; due to

connections to the same brain centers– Hypothalamus– hippocampus

C. Effects of Smell and Texture on TastePrinciple Involved

Negative results can be attributed to the ff.:Nervous system damage; commonly in orbitofrontal area,

(Brodmann’s Area)Disorders:Anosmia – partial or complete loss of smellHyposmia–reduced ability to smell and to detect odorsDysosmia – qualitative alteration or distortion of the

perception of smell– Parosmia – altered perception of smell in the presence of an odor– Phantosmia – perception of smell without odor present– Agnosmia – inability to classify or contrast odors although able to

detect them

C. Effects of Smell and Texture on TastePrinciple Involved