Carolina Biological
$89.50
PERIPHERAL BLOOD FLOW KIT
Background Information
•Body temperature is the balance between heat
production and heat loss.
•The temperature of the skin plays a role in
determining the rate at which body heat is
gained or lost.
•Peripheral blood flow is blood flow to the
superficial tissues.
•Heat elimination depends on the amount of
peripheral blood flow at any given time.
•Heat exchange across the body is not uniform
depending on the amount of blood vessels in
any given area.
•Peripheral circulation is controlled by the
autonomic nervous system and influenced by
the hypothalamus.
•Peripheral circulation can conserve body heat in
cold environments (blood vessels constrict) or
eliminate excess heat in warm environments
(blood vessels dilate)
Liquid Crystals
 Special molecules
 Temperature variations alter the shapes of
the liquid crystal molecules
 The change in shape alters the wavelengths
of light the crystals reflect
 By using liquid crystals and observing color
changes we will be able to accurately
measure
 temperatures
 temperature gradients
 temperature changes
 Carolina crystals have a two degree wide
operating range
 Allows for one degree above and one degree below
event temperature on the thermographic sheets
 Thermographic sheets in this kit respond to skin
temperatures of approximately
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28 oC
30 oC
32 oC
33 oC
34 oC
How the thermographic sheets
work
 An initial brownish color appears while the
crystals are warming up
 Yellow is a transitional color
 The color transition is red-green-blue
 Green signifies when the event temperature has
been reached
 Example
 If you are using a 32 oC thermographic sheet, any green
areas will be approximately 32 oC; brownish-red areas will
be cooler than 32 oC and blue areas will be warmer than
32oC
Important Note
Do not directly touch
the thermographic
sheets
(this may alter your temperature readings)
Roles in the lab
 Experimenter
 Applies the thermographic sheet to the test
subjects hand
 Test Subject
Procedure
Part A: Regional Variations
 Experimenter selects thermographic sheet and
applies it to the back of the test subjects hand. If
the sheet turns a uniform dark blue, the
Experimenter should choose a sheet with a
higher event temperature. The goal is to select a
sheet that undergoes a gradual, distinct color
change when placed on the test subject’s hand.
 Observe the color pattern that emerges on the
sheet.
 Repeat using different body locations, such as:
the cheek, the forehead, the neck, the knee, and
the inside of the forearm
 What caused the blue lines of streaks to
appear on the liquid crystal sheet when it was
placed on the back of the hand?
 Based on your observations, which areas of
the body were the warmest?
Part B: Effects of Gravity
 Test subject to raise arm to chest level and extend outward
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to side (maintain this position)
Experiment places thermographic sheet on back of test
subjects hand
As sheet stabilizes look for blue vein patterns
With sheet still in place test subject should extend hand
straight up in the air for 1 minute
Watch for changes in color pattern in areas overlying the
veins.
Return to initial position and watch the colors stabilize
Test subject should then lower arm to side for 1 minute
Watch for changes in color pattern in areas overlying the
veins.
 What accounts for the color change when the
hand is raised above the head?
 What accounts for the color change when the
hand is lowered to the side?
Part C: Effects of Temperature
 Experimenters should place a thermographic sheet
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on test subjects hand
Look for blue vein patterns
Test subject should place fingers in a beaker of warm
water for 1 minute (Do NOT get thermographic
sheets wet)
Observe color changes
Test subject should place fingers in a beaker of cold
water for 1 minute (Do NOT get thermographic
sheets wet)
Observe color changes
Repeat this sequence 3 times
 How did the color pattern change after the
test subject’s fingers were placed in warm
water?
 What caused this color change?
 How did the color pattern change after the
test subject’s fingers were placed in warm
water?
 What caused this color change?
Possible Variations
 Have students make temperature color
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sketches
Have students make temperature data table
Graph temperature data table to compare
regions
Have students design their own experiments
to test temperature and/or gravity
Test temperature and/or gravity in different
regions of the body