1

Gustation: detect chemicals dissolved in a solution

• Four basic taste qualities– sweet, sour, bitter, salt

• Taste Mixtures– taste suppression: sugar vs. coffee– taste modification: toothpaste vs. juice– taste adaptation

• Flavor – not the same as taste

• an apple, onion, and potato all have the same taste, they differ in flavor– flavor is composed of: taste, smell, touch (texture), temperature, color, and

sometimes pain– learned preferences for flavors: previous experiences, culture.

2

Survival Significance of Tastegauge the edibility of food

Taste Stimulus Significance

SweetComplex organic

molecules(sugars and carbohydrates)

energy

Salt NACL Nerve conduction

Sour Acids (H+)Spoiled foodor vitamins

BitterOrganic alkaloids

Metallic salts poison

3

Tongue Localization

The entire surface can detect all tastes.

However, the tip is most sensitive to sweet, the sides to salt and sour, the back of the tongue and the soft palate respond most strongly to bitter.

4

Physiology of Taste

1. Molecules in solution make contact with gustatory hairs

2. Receptor releases neurotransmitter

3. Causes graded potential in sensory dendrite and leads to an action potential

5

Sensory Coding

• Across fiber pattern coding

– the pattern of activity across many receptors codes for the taste

– the same receptors may respond but with different relative amounts of activity

6

Neural pathway of taste

Specific tastes are identified in the insular cortex