Transcript 31.2 Immune System

31.2 Immune System
KEY CONCEPT
The immune system consists of organs, cells, and
molecules that fight infections.
31.2 Immune System
• The immune system is the body system that fights off
infection and pathogens.
31.2 Immune System
• Think of your body as a heavily guarded castle. When
pathogens invade they must break down the outer wall or
find a way around it. If the intruders get past the physical
barriers, they must face your body’s fighters in hand-tohand combat.
• Invaders are winning= you are sick
• Your body is winning= you are healthy
31.2 Immune System
What is our first line of defense?
• SKIN!!!!!!!
– Cuts and wounds are entry points
What are the other entry points?
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Eyes
Nose
Ears
Mouth
Excretory Organs (lungs)
31.2 Immune System
– Skin is a physical barrier to infection
- It is your first line of defense!
– Mucous membranes in these openings trap pathogens
entering the body.
– The circulatory system transports immune cells.
31.2 Immune System
SKIN
• First line of defense against pathogens
– Protection from infection
– Oil glands in skin
- Inhibit the growth of bacteria
31.2 Immune System
• How do we heal?
*Discuss with your table the order in which a cut heals.
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Cut yourself
Bleed
Form blood clot
Blood clot dries out- Scab is formed
Skin cells divide and multiply- (mitosis)
Scab falls off
*Creates a barrier between bacteria on skin and the tissue below
31.2 Immune System
Six main types of white blood cells
1) phagocyte- Destroys viruses, bacterium,
and fungi by engulfing them
Ex: macrophage
31.2 Immune System
2) T cells- Destroy body
cells that are infected
3) B cells- Produce proteins
that inactivate pathogens
that haven't infected body
cells yet
31.2 Immune System
4) Complement Proteins: made by white blood cells, and
weaken pathogen’s cell membrane allowing water in so it
will burst
31.2 Immune System
5) Antibodies: made by B cells
• Attack pathogens by “binding” themselves to the
pathogen to prevent them from attacking healthy cells
• Cause pathogen’s to clump, making it easier for
phagocytes to engulf and destroy
31.2 Immune System
6) Interferons: produced by body cells infected by a virus
• Stimulate uninfected body cells to produce enzymes that
will prevent viruses from entering and infecting them
• ***If a virus can’t enter it- it can’t reproduce!
31.2 Immune System
•Body Story: Body Snatchers
•“Body Snatchers Video Notes”
• *Focus on the changes of the body after
being infected with influenza virus
• At least 10 bullets
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31.2 Immune System
1.
What does the virus do to her cells?
2.
What causes Holly’s pain symptoms? Why?
3.
Your body has a natural thermostat (98.6). Why does her body
react with a fever?
4.
Why was it “good” that Holly couldn’t find pain medicine?
5.
Why does it take the body so long to find the helper T and B
cells?
6.
The video said the specific T cell had been “waiting for 25
years” Hypothesize where you think she got it•14from?
31.2 Immune System
•1. What does the virus do to her cells?
•“Hijacks her cell”- forces it to produce more of the virus
•2. What causes Holly’s pain symptoms? Why?
•Holly’s body is creating the pain symptoms. This lets her know that something is wrong- It
is the result of her body fighting the invader. Allows her to “rest” so her body can use her
energy to fight the invader.
•3. Your body has a natural thermostat (98.6). Why does her body react with a fever?
•98.6 allows for a perfect “breeding ground” for the virus. By heating up her body the virus
cannot produce at such a fast rate.
•4. Why was it “good” that Holly couldn’t find pain medicine?
•Pain medicine would reduce her fever, allowing the virus to produce at its full rate.
•5. Why does it take the body so long to find the helper T and B cells?
•They are only 2 cells in trillions. Your body needs to locate the proper cells to fight the
virus.
•6. The video said the specific T cell had been “waiting for 25 years” Hypothesize where you
think she got it from?
•She was born with it. Passed on from her mother to her.
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