1. Sponge: Set up Cornell Notes on pg. 53
Topic:
12.4: Sense of Taste
Essential Questions:
Why is saliva necessary to taste?
On the bottom ½ of pg. 52: Divide the pg. into four squares, draw pictures or labels of food that fits into each of the four major taste sensations. *5 each
12.4: Sense of Taste
2.1 Atoms, Ions, and Molecules

2. Pg. 52
Which organ in the tongue supplies your brain with the information that can then be interpreted as “taste”?
TASTE BUDS!!!

3. Sense of Taste Taste Buds Organs of taste Over 10,000 taste buds
Each taste bud has taste cells (taste receptors)
Located on the surface of tongue, roof of mouth, linings of cheeks and walls of pharynx

4. What type of receptor is used in the special sense of “taste”?
Chemoreceptors!!!!

5. A chemical to be tasted must dissolve in saliva, the watery fluid surrounding the taste buds
Secreted from the salivary glands

6. Taste Receptors Taste Receptors chemoreceptors
taste cells – modified epithelial cells that function as receptors
taste hairs –microvilli that protrude from taste cells; the sensitive parts of taste cells

7. Tastebuds on the surface of the tongue are associated with the elevations called papillae

8. Taste rapidly undergoes sensory adaptation
One can avoid the loss of taste by moving bits of food over the surface of the tongue to stimulate different receptors at different moments

9. Taste Nerve Pathways
Sensory impulses from taste receptors travel along
cranial nerves to
medulla oblongata to
thalamus to
gustatory (taste) cortex for interpretation

10. Taste Sensations Four Primary Taste Sensations:
sweet – stimulated by carbohydrates
sour – stimulated by acids
salty – stimulated by salts
Widely distributed
bitter – stimulated by many organic compounds
Extreme sensitivity to bitter taste is inherited
Alkaloids- which include many poisons; spitting out may be a protective mechanism
*umami- “savory” or “meaty”

11. What is PTC? (phenylthiocarbamide)
It's a chemical. About 3 out of every 4 people can taste it. And if you can taste it then you'll think "yuck!"
Scientists believe chemicals similar to PTC helped our ancestors stay away from some toxic plants. Now we just find chemicals similar to PTC in things like broccoli and brussel sprouts.
Sorry, broccoli isn't toxic, so you'll still have to eat it if your mom says so.

12. Draw a diagram of the taste sensations on the top ½ of pg. 52
Location of Taste Sensations
Draw a diagram of the taste sensations on the top ½ of pg. 52

13. There is a lot of discrepancy in the scientific community on whether or not there are specific locations for each type of taste receptor. Many scientists believe that each taste cell has receptors for all of the five tastes.

14. Each flavor we experience results from one of the primary sensations or from a combination of 2 or more of them
All taste cells probably respond to more than one taste sensation
one taste sensation is likely to dominate

15. Can any other type of receptor (besides chemoreceptors) be stimulated by certain types of food?
Pain receptors
Spicy food
Hot (temperature) food

16. Chemicals in some foods may activate pain receptors
Spicy foods

17. EQ: On bottom of pg. 52: Divide the pg
EQ: On bottom of pg. 52: Divide the pg. into four squares, draw pictures or labels of food that fits into each of the four major taste sensations. *5 each

18. Sweet
Sour
Bitter
Salty

19. Clinical Application 12.3 Smell and Taste Disorders
Pg. 58
In what type of situation would a poor or absent sense of smell be dangerous?
Why is the sense of smell vulnerable to damage?
List 10 ways taste disorders can be triggered.
Why did the beer and cola taste bitter to the mountain climbers?
Similar to the hikers’ experience, what are 2 other medical treatments that may cause a “metallic” taste to food and drink?
What is cacosmia? Explain what it does to your sense of taste.