290 Notes to Instructors
Notes to Instructors
Chapter 43 The Immune System
What is the focus of this activity?
Many aspects of the immune system function in a series of domino effect–like responses.
What is this particular activity designed to do?
Activity 43.1 How does the immune system keep the body free of pathogens?
What misconceptions or difficulties can this activity reveal?
Activity 43.1
Question 1: All students understand that bacterial and other infections are “bad”;
Answers
Activity 43.1 How does the immune system keep the body
free of pathogens?
Draw a Rube Goldberg cartoon-type diagram or develop a dynamic (claymation-type)
Activity 43.1 291
Here is an example of a Rube Goldberg–type drawing:
lf
Terms
bacterium or virus particle
helper T cell receptor
helper T cell
cytotoxic T cell
active cytotoxic T cell
macrophage
B cell
memory helper T cell
memory B cell
memory T cell
plasma cell
interleukins (or cytokines)
CD4 protein
MHC molecules
antibody
antigen
epitope
thymus
bone marrow
hypothalamus
fever
clonal expansion
self versus nonself
After you have completed your model or diagram, use what you have learned
to answer the questions on the next page.
1. What are pathogens? Why do we need to prevent them from colonizing our bodies?
If pathogens do manage to colonize, what effects can they have?
Pathogen is a generic term for any disease-causing organism. Pathogens include
disease-causing bacteria, viruses, fungi, and protists.
292 Activity 43.1
2. What general defense mechanisms does the body use to help prevent colonization by
pathogens? For example, what general defense mechanisms are involved in local
inflammatory responses?
The skin and mucous membranes act as physical barriers to the entry of pathogens.
3. In specific immunity, how do B cell responses differ from T cell responses?
B cell responses
Individual B cells respond to specific types
of foreign antigens by secreting antibodies
that interact with the antigen and cause cells
T cell responses
When body cells become infected with a
pathogen, a piece of foreign protein from the
pathogen interacts with an MHC molecule.
Activity 43.1 293
4. If about 105genes are available in the human genome to produce proteins, how
can we produce more than 10 ⫻106different kinds of Ab receptors (proteins)
on B cells?
Although Campbell Biology, 9th edition, doesn’t explain this in any detail, the
information that the immune system can produce more types of B cells than there are
5. How does HIV affect the immune system?
HIV (human immunodeficiency virus) targets cells that display both the CD4