Transcript 4-Taste and smell - Science-with

Chapter 14.1
Pages 446-448
TASTE AND SMELL
 Taste receptors
 Found in diff. locations in
diff. species
 Octopuses – tentacles
 Crayfish – antennae
 Insects - legs
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Taste

 in humans, receptor cells for taste are modified
epithelial cells organized into taste buds
 there are five taste perceptions:





sweet
sour
salty
bitter
umami (savory)(elicited by glutamate)
 Once dissolved, specific chemicals stimulate
receptors
1) Taste
4 types of taste that are stimulated by dissolved
chemicals in specific taste buds:
•Sweet
•Salty
•Sour
•Bitter
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Figure 16.4
(a) Specialized hairlike receptor ends in
the tongue detect
specific chemicals,
Axons from the
sensory neurons are
shown in yellow, (b)
Taste buds of a rabbit
tongue, The taste bud
appears as a bulblike
structure,
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
 Taste receptors
http://www.mhhe.com/biosci/genbio
/espv2/data/animals/003/index.html
 Click on taste sensation
•Taste receptors and olfactory create
the perception of taste
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Smell (olfaction)

 Detection of a specific airborne chemicals that
stimulates an olfactory cell to produce action
potential that is perceived in the olfactory bulb.
 Olfactory receptor cells are neurons that line the
upper portion of the nasal cavity
 Binding of odorant molecules to receptors triggers a
signal transduction pathway, sending action
potentials to the brain
DETECTING SMELL
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
• Olfactory cells demonstrate
sensory adaptation
• People who live in cities with
pulp mills adjust to odor
• Odor seems to fade after a short
period of time
Taste
http://www.bbc.co.uk/science/
humanbody/body/factfiles/taste/
taste_ani_f5.swf
Smell
http://www.bbc.co.uk/science/
humanbody/body/factfiles/smell/
smell_ani_f5.swf
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3) Sensory receptors in human skin
•Despite an incredible collection of specialized sensory
receptors, much of environment remains undetected
•Each
mechanoreceptor is
a modified dendrite
of a sensory neuron
Skin receptors
http://www.sumanasinc.com/webcontent/animations/content/skinreceptors.html
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Senses game

 http://www.bbc.co.uk/science/humanbody/body/
interactives/senseschallenge/
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