The Immune System

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The Immune System
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What is the Immune System?

• A group of defenses that protects the body
  against disease-causing organisms.
• Pathogen- Any disease causing organism.

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First Line of Defense

• Skin- The skin keeps most pathogens from entering
  into the body.
• If the skin is cut or torn, pathogens can get in.
• Respiratory System- Mucous and cilia in your
  windpipe trap pathogens.
• Sneezing and coughing gets rid of these trapped
  pathogens.

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First Line of Defense

• Digestive System- Saliva and acids work to kill
  pathogens.
• HydroChloric Acid- Digests your food and many
  pathogens you eat.
• Circulatory System- White blood cells attack and
  kill pathogens.
• Increasing your body temperature (fever) kills
  pathogens too.

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Inflammation

• When an area is infected with pathogens, it
  becomes inflamed.
• Inflamed areas become red, swollen and painful.
• White Blood Cells go to inflamed areas to fight
  off the pathogen.
• Puss- Dead white blood cells that have died
  fighting off the infection.

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Active Immunity

• 1. A pathogen (bacteria, virus) enters your
  body, and you get sick.
• 2. White Blood Cells produce Antibodies-
  Specific proteins that attack the pathogen.
• 3. The pathogen dies, and you get better.
• 4. That Antibody stays in your blood incase the
  pathogen comes back later.
• 5. If the pathogen comes back, white blood cells
  make more Antibodies to fight off the attack,
  keeping you from getting sick.

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Pathogen enters your body.
Antibodies are made.
Pathogen dies.
Active Immunity
If pathogen returns, antibodies build up again
Antibodies stays in your blood.
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White Blood Cell
Pathogens
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Antibodies
White Blood Cell
Pathogens
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The white blood cells stay in your blood for
years.
If a pathogen returns, years later
Antibodies are there, to fight off the pathogen.
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Pathogen dies before you get sick!
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Vaccination

• Process of giving a vaccine to help give active
  immunity.
• Vaccine- Preparation of dead or damaged
  pathogens.

-After you get the vaccine, your body will begin
making antibodies to fight off the pathogen. -If
you ever get the real pathogen, your body will
know how to kill it quickly with antibodies.
-Your body REMEMBERS which antibodies attack
which pathogens!
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Passive Immunity

• When antibodies are made in another person or
  animal, and then given to you.
• Newborn babies have Passive Immunity from
  antibodies in their mothers blood.
• This Passive Immunity only last for a few months,
  so the baby will need vaccines to build up their
  own Active Immunity.

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Disease-Causing Organisms

• Bacteria- Tetanus, strep throat, and pneumonia.
• Virus- A small piece of DNA surrounded by a
  protein coat.
• A virus Tricks your cells into making more
  viruses.
• Can cause the flu, AIDS, measles, mumps and
  chickenpox.

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Disease-Causing Organisms

• Protist Malaria is spread by mosquitoes and
  African Sleeping Sickness is spread by Tsetse
  fly.
• Fungi Ringworm and Athletes foot.

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Infectious Disease

• Any disease that is caused by a virus, bacterium,
  protist or fungus and is easily spread.
• Infectious Disease can be spread by contact,
  water, air or food.
• Biological Vector- Any organism that is carrying
  the disease.

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Virus
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Bacteria
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Protist
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Fungus
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