This
activity page will offer:
- A
chance to observe fluid moving through a one-way valve
- An
opportunity to build a model of a valve.
- An
opportunity to learn more about biotechnology design.
MATERIALS
- Two
8-inch sections of clear plastic tubing,1-2 inches in diameter*
- Small
elastic band
- Scissors
- Rubber
glove (such as those used for dishwashing)
- Duct
tape
- Cup
- Water
*This
type of tubing may be found at hardware, car care, small
engine, and marine supply stores.
PROCEDURE
- Use a scissors to cut off one of the fingers from the
glove.
- Cut an "X" in the tip, with each slit about one-inch in
length. SEE DIAGRAM B & C.
- Insert the glove finger into one section of wide, clear
plastic tubing. Invert and roll a small section of the fabric
of the glove back over the tube to form a collar.
- Secure the exposed collar to the plastic tube with either
duct tape or an elastic band. SEE DIAGRAM E.
- Place the other tube section on top of the balloon end
of this tube.
- Use duct tape to secure and form a waterproof seal around
the joined edges of the two tubes. SEE DIAGRAM F.
- Fill a small cup with water. Over a sink, carefully pour
the water into the tube assembly so that is flows into the
inside of the glove finger (Labeled "TOP" in diagram). Observe
what happens as the fluid impacts the glove finger.
- Turn the tube assembly upside down and again pour a cup
of water into the tube. What happens this time? Write down
your observations.
Questions
- What did the glove represent?
- What did the plastic tubing represent?
- Why did you invert the glove in step 9?
- Describe the mechanical action of the valve.
EXTENSIONS
Veins Only
Although
there are valves in veins to prevent the backward ebb of blood,
no such parts are found in arteries. Why?
HINT: Consider the difference in pressure found within an
artery and a vein.
Who
Gets the Heart?
There are not enough hearts or other transplant organs to
meet the needs of the critically ill. Unfortunately, some
people die while they wait for an available organ. Suppose
you were in charge of deciding who was going to get the organ
and who must continue to wait. What would you base this decision
on? Would factors such as age, family, gender, finances, race,
health issues, or role in society enter into this critical
choice? If so, how?
eBay
Debate
Perhaps you've heard of eBay? It's an online auction in which
items that range from dinettes to dinosaur skulls are offered
for sale. A while back, individuals began to post "organs
for transplant" on this site. One kidney went as high as $5.7
million dollars before eBay stopped the bidding. The sale
of kidneys or any other body parts is illegal -- yet the marketing
of body parts for profit is a potential source of organs.
What do you think? Should people be able to sell one of their
organs? Why or why not? Suppose the money was needed to finance
a lifesaving operation? Would this make a difference?
Presumed
Consent?
In the US, the current organ transplantation process depends
mostly upon voluntarism. You have to "sign-up" in order to
release your organs for transplantation. In contrast, in some
foreign countries, including France, the medical establishment
assumes "presumed consent." In other words, they can access
the organs of a deceased individual without written consent.
If you do not want your organs donated, you need to file legal
paperwork stating so. Do you think that presumed consent should
replace the voluntarism policy now in place in the United
States? Why or why not? In the absence of a written statement
granting permission here in the US, surviving family members
can grant access to the deceased's organs. Often donated organs
must be harvested immediately following the death of the donor.
How might grief affect access to such organs?
WEB
CONNECTION
Interview
with Dr. Mehmet Oz
http://www.accessexcellence.org/WN/NM/ozpage1.html
An informative interview on heart-assist devices that includes
a virtual heart transplant lab.
Heart
Valve Information Page
http://www.csmc.edu/cvs/md/valve/default.htm
This site includes images about a variety of artificial heart
valves.
Heart
Transplant Program: Temple University
http://www.temple.edu/heartfailure/html/heart_
transplant.html
Information on one hospital's heart failure and transplant
programs.
The
activities in this guide were contributed by Michael DiSpezio,
a Massachusetts-based science writer and author of "Critical
Thinking Puzzles" and "Awesome Experiments in Light & Sound"
(Sterling Publishing Co., NY).
Academic Advisors for this Guide:
Corrine Lowen, Science Department, Wayland Public Schools,
Wayland, MA
Suzanne
Panico, Science Teacher Mentor, Cambridge Public Schools,
Cambridge, MA
Anne E. Jones, Science Department, Wayland Middle School,
Wayland, MA
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