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					        Linking Two Worlds: Using Animals to Learn How the Human Body Works

Purpose

Introduce students to concepts of physiology as it relates to incorporation of dietary items into
tissues and the use of these dietary nutrients to fuel metabolism

Concepts discussed

      What are Stable Isotopes?
      How nutrients are stored in the body for future use (fat and glycogen)
      How nutrients are mobilized to meet energy demands
      What does the C in the CO2 we exhale tell us about the metabolic fuels we are burning
      What do animals tell us about our own physiology


Materials (provided)

500ml nalgene bottle fitted with a                    scotch tape
one-way stopcock valve                                LabconCo gas collection vials
kimwipes                                              Black sharpie
Kool Aid                                              Beet Sugar
Cane Sugar                                            10 House Sparrows
Students

Methods

Students

At the beginning of class students will breathe into CO 2 collection vials to determine the time
zero isotope composition of each students CO 2. Students will then drink one cup of Kool Aid.
Half of the class will drink Kool Aid made with beet sugar (C3) and the other half Kool Aid
made with cane sugar (C4). Every 15 minutes for one hour a sub-sample of students from each
group (C3 or C4) will breath into CO2 collection tubes. From this we can determine the time
from ingestion, absorption, to utilization as a metabolic fuel. Tubes will be sealed and analyzed
at UW. The data will be returned to the students and posted on my website where they can
review and talk about the results.

Sparrows

While students are absorbing sugars from the recently ingested kool aid, they will be collecting
CO2 from house sparrows that have been raised on two different diets. The results will yield
very different carbon isotope ratios in exhaled CO 2 . With assistance, individual house sparrows
will be placed in a 500ml nalgene bottle for one minute. After one minute, a 50ml sample of air
will be withdrawn by placing a syringe on the one-way stopcock valve. The gas sample will then
be injected into a sealed CO2 collection vial. I will already have a dataset from this group of
sparrows for the students to see in class the same day. This data set will then be used for class
discussion about the results of the experiment.

				
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