SKILL FOCUSHypothesizingInitiating and planningPerforming and recordingAnalyzing and interpretingCommunicating resultsInvestigation
DESIGN YOUR OWN
4•AProblem
How does coffee affect the physiology of the body?Hypothesis
Create a hypothesis related to one physiological effect
of consuming coffee.CAUTION: Due to health concerns, it may not be
appropriate for some students to participate as
subjects in this investigation. Be sure that
students do not exceed their normal coffee intake.Materials
Select your own materials.Experimental Plan
1.After deciding which physiological reaction you want
to measure, design an experiment that allows you to
measure the effect of coffee.
2.Be sure to establish proper controls so you can
compare your results before and after the ingestion
of coffee.
3.Establish the amount of time required, and ask your
teacher to approve your experimental design and to
arrange for any equipment you may need.The Physiological Effects of Coffee
This investigation gives you an opportunity to explore one of the body’s feedback
systems. You will discover how coffee, which is consumed by millions of
Canadians each day, affects the homeostatic processes of the human body.
Coffee contains caffeine, a stimulant and diuretic that affects the body in a variety
of ways. Begin your investigation by using the Internet or your library to research
the positive and negative effects of coffee.118 MHR • Unit 2 Homeostasis
Biology Magazine TECHNOLOGY • SOCIETY • ENVIRONMENT
Kidney Transplants
When the first kidney transplant occurred 40 years ago,
it was a major medical breakthrough. In the year 2000
there were 1112 kidney transplants performed in Canada.
Of these, 724 used cadaveric (deceased) donors and 388
used living donors.
The major problem with transplant surgery is not in the
operating room — it is in finding suitable donors. In
Canada, most donors are victims of stroke or head
trauma (often related to motor vehicle accidents) who are
being maintained on a ventilator. Only two to three
percent of all deaths in Canada are the result of brain
death, and that pool of potential donors is further limited
by the fact that hospitals require permission from the
relatives of the donor to perform a transplant. Ninety-six
percent of relatives agree to organ donation if they know
the wishes of the potential donor, while only 58 percent
agree if the issue has not been discussed in advance.
Canada has one of the lowest organ donation rates
among industrialized countries. There are fewer than
14 donors per million in Canada, compared with more
than 30 per million in Spain. Why? This disparity is partly
due to Canada’s “opting in” policy — donors and/or theirrelatives must give permission for transplantation of
organs. In contrast, many European countries have an
“opting out” policy, in which permission is assumed
unless the potential donor has specifically requested
not to be an organ donor.What Are the Ethical Considerations?
The use of living donors is a growing trend. People can
survive with only one kidney, but the donation of a kidney
by a living donor creates a number of ethical problems for
the medical community. There are risks associated with
any surgery — should a doctor risk the life of a healthy
person in an attempt to aid someone who is ill? In
addition, there is the problem of “informed consent.” Can
a doctor be sure that a living donor is a willing participant
and is not the victim of pressure from relatives? Can a
doctor proceed with the operation if he or she suspects
that the donor is receiving some form of benefit in
exchange for donating a kidney?
An additional ethical problem is looming on the
biotechnological horizon. Pig tissue (not organs) has been
used in clinical trials to replace damaged human tissue.
Pig organs are similar in size and shape to their human
counterparts, which makes pigs good candidates for