Science Bus Lesson: The Immune System
This topic might seem sort complicated for one lesson, but I think we can deliver it in a
manageable way that the kids can digest. I tried to make it as simple as possible. Let me
know if you have any suggestions or corrections.
I would like to cover the four concepts related to the immune system. They will be
demonstrated through a series of hands-on activities involving little cartoonish cells I’ve
made. The terms aren’t so important as much as the general ideas of how the body
defends itself.
1) Innate immune system - white blood cells that eat anything foreign
2) Active immune system - T-cells (there are others, but we’ll just look at these) which
pick out specific germs.
3) Shots and Vaccines – why do they work?
4) Allergies (if there’s time) – Immune system gone haywire.
INTRO:
Q: Who has been sick before?
Q: What makes you sick?
A: Several levels of answers...Cold, flu, germs, viruses, allergy, etc.
Q: How do you get better?
A: Medicine? Rest?
Q: Who here has allergies?
Q: Why do you get shots?
A: We'll learn this in the lesson.
These are all related to the immune system. Does anyone know what that is? Your every
day surroundings contain lots of things that make you sick. How does your body
overcome this? Your immune system.
Your immune system is made up of cells (what are cells?) and smaller objects that are
very good at picking out bad things in your body that aren’t meant to be there. What are
those bad things again?
T
Innate (left) and Active (right) Immune
Systems…explained later.
PART I – Innate Immune System
Your body has many cells called “White blood cells.” They work by engulfing foreign
bodies, which then prevents those bodies from hurting you.
The activity: In groups, students will divide into two competing sections. One will be
cutting out paper germs, and the other will be cutting out paper white blood cells; the cut
out objects will be put on the table. I haven’t completely worked out the timing on this,
but the germs will get a head start, and the white blood cells will be cut out faster by
virtue of having a simpler shape. Each white blood cell can eat one germ by sitting on top
of it. We’ll see which side wins (by having a higher population) after some time limit.
This is relatively simple, sort of a primer.
PART II – Active Immune System
White blood cells can’t find everything that makes you sick. This is why there is another
type of cell to help you. It is called a T-Cell. A T-Cell is specifically matched to each
germ, and once you have that T-Cell in your body, you can more easily defeat that germ.
The activity: Now all students are on defense. The tutor makes the germs. The students
get blank T-Cells and now need to make specific T Cells to defeat those germs. This is
done by cutting out a mouth out of the T-Cell that then matches the germ (see below).
While the students are trying to cut out the mouth, the tutor keeps making different kinds
of germs. I will make five or six kinds of germs. Once the specialized T-Cell is cut out by
the student, he or she can then pull off all of the germs that match the mouth. This is sort
of a fun race.
One aspect of the active immune system is “memory.” The T-Cells stay in your body and
can defend against future outbreaks years later.
T Cell
T
Specialized T Cell
Germ
+
=
T
T
PART III – Shots/Vaccinations
Wouldn’t it be nice if you could train your cells to notice the germs, before you get sick?
When you get a shot, or vaccination, you are getting germs that are already dead, so they
don’t keep replicating. Then, your T-Cells can learn what to attack, and so when you get
sick, you can quickly respond.
The tutor will cut out the dead germs (denoted by the crossed-out eyes) and then give the
students time to make the T-Cells. The dead germs don’t replicate, so the students can go
at a leisurely pace. Then, when the real attack happens with live germs, the students can
quickly sweep away all the attackers with the prepared T-Cells and win.
PART IV – Allergies
Q: Who has had an allergy? What were you allergic to?
An allergy is your body’s response to some foreign body. Examples are pollen, cat
dander, peanuts, bee stings, etc.
Here, your body hurts you by over-responding. That is why allergies sometimes resemble
when you are sick.
I’m not sure I’ll do an activity here.
Pollen
Too many cells!
Conclusions:
What did we learn? About the immune system
What do these White blood cells do? They eat everything bad they can find
What do these T-Cells do? They are specialized; eat only things that match.
Why do you want to get your shots? So your T-Cells can be trained
What is an allergy? Your immune system over-responding.
If the lesson is short, I may show some pictures of various bacteria/viruses that make
people sick. I might show where all the cells are produced in the body.