Name:____________________________________________________Date:__________________Period:__________
Basics of the Immune System - Day 5
Objective: Students will be able to understand the basic differences between specific and non-specific immune responses
QUESTION: How does the body defend itself from diseases?
Answers will vary.
Part 1 - Research
1. 1st Level of Defense
What do you think the following images are of?
The images are of bacterial, viral and parasitic diseases.
Defense
Example
How you think it would stop a virus, bacteria, or parasite
Hair
Eyelashes
Hair traps foreign invaders before they can touch the skin
Skin
Skin
The skin locks out foreign invaders since it is basically water tight
Mucous
Snot
Mucous is a thick substance that traps and kicks out foreign invaders
Chemicals
Stomach Acid
The stomach acid kills any pathogens by having a harsh environment
2. 2nd Level of Defense
Take a look at the image and/or video of phagocytosis. In the space below draw and describe how our cells protect
our bodies from foreign invaders.
Answers will vary, but students should explain that the white
blood cell hunts and eats the foreign invader
How do you think a fever would help you fight off a viral, bacterial or parasitic invasion?
Your Thoughts
Notes
Fevers are induced by the body as a simple way to make
the environment less hospitable to the foreign invaders.
Many times the increase in temperature stops the
invader from reproducing or obtaining energy
3. 3rd Level of Defense
The human body has two general ways of protecting itself from
foreign invaders (viruses, bacteria, and parasites). The processes
are known as non-specific and specific defense.
Non-specific defenses start at the surface of our bodies and can
include hair, skin, sweat, mucous, tears, and even saliva. These
defenses generally block or trap foreign invaders before they get
the chance to enter the body. If by chance, these pathogens get
past the surface area, we have cells that patrol the blood stream
looking for anything that does not belong. These white blood
cells are referred to as macrophages and they eat (through a
process called phagocytosis) any foreign object. These defenses
are non-specific because they do not target any one bacterial or
viral disease.
Specific defenses are referred to as immunity. Immunity refers to
the body's ability to "learn" and target specific bacterial and viral
diseases. Each foreign invader has a marker called an antigen.
Your white blood cells (called lymphocytes) learn these antigens
and create antibodies that signal to the white blood cells that they
are dealing with a specific foreign invader and it has to be
destroyed. This level of defense is very important because many
bacteria and viruses have learned to camouflage themselves
inside the body. An amazing fact is that you have white blood
cells that are called memory cells. These cells recall all diseases
that have invaded your body and they teach other white blood
cells how to kill the pathogens before they can make you sick
again.
Read the article to the right and describe The difference
between non-specific and specific defenses:
Non-specific defenses attack any all foreign invaders,
and do not target specific diseases
Specific defenses learn to target, find and kill specific
foreign invaders.
Why would your body need a specific defense system if
you already have a non-specific defense system?
Since most foreign invaders are blocked by our nonspecific defenses, the need for specific defenses becomes
very important. The foreign cells that get past our nonspecific diseases are much savvier and need a specific
and targeted response.
Conclusion: If you were an evil bacterial cell, how would you enter the body and avoid detection in the blood?
Answers will vary, but could include:
Non-Specific Defenses: Hair, Skin, Mucous, Stomach Acid, and Phagocytosis
Specific Defenses: Immunity, learning and targeting cells, lymphocytes,
antibodies and antigens.