31.4The Senses-2
Suri
Smell and
Taste
chemoreceptors
化学感受器
 How are the senses of smell and taste similar?
 Sensations of smell and taste are both the result of
impulses sent to the brain by chemoreceptors.
 In fact, much of what we commonly call the “taste”
of food and drink is actually smell.
Smell and
Taste
 To prove this to yourself, eat a few bites of food
while holding your nose. You’ll discover that much
of the taste of food disappears until you release
your nose and breathe freely.
Activity
1.
Set students to single and double numbers
2.
Let single number students close their eyes and pick one type
of candy.
3.
Let double number students close their eyes and pick one type
of candy.
Smell and
Taste
taste buds
 The sense organs that detect taste are the taste buds.
 Most of the taste buds are on the tongue, but a few
are found at other locations in the mouth.
 Sensory cells in taste buds respond to salty, bitter,
sweet, and sour foods.
THE
DISCOVERY
OF UMAMI
 The taste sensation umami was discovered in the early
1900s by Kikunae Ikeda, a professor of chemistry in Tokyo,
Japan. His worked was based on his observation that a
particular soup ingredient commonly used in Japan had a
taste that did not fall into the established taste categories of
salty, sweet, bitter, or sour. By isolating the chemical
compounds in this soup ingredient, he was able to
determine that the taste associated with umami is due to
glutamate, an amino acid that is found naturally in meats
and some vegetables. Ikeda developed the food seasoning,
monosodium glutamate—MSG—based on his research.
Analyzing
data