KEY CONCEPT The immune system consists of organs, cells, and molecules that fight infections.

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KEY CONCEPTThe immune system consists of organs,
cells, and molecules that fight infections.
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• The immune system is the body system that fights
  off infection and pathogens.

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• 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 bodys fighters in hand-to-hand
  combat.
• Invaders are winning you are sick
• Your body is winning you are healthy

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What is our first line of defense?

• SKIN!!!!!!!
• Cuts and wounds are entry points

• What are the other entry points?

• Eyes
• Nose
• Ears
• Mouth
• Excretory Organs (lungs)

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• 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.

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SKIN

• First line of defense against pathogens
• Protection from infection
• Oil glands in skin
• Inhibit the growth of bacteria

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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

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Six main types of white blood cells

• phagocyte- Destroys viruses, bacterium, and fungi
  by engulfing them
• Ex macrophage

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• 2) T cells- Destroy body cells that are infected

3) B cells- Produce proteins that inactivate
pathogens that haven't infected body cells yet
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• 4) Complement Proteins made by white blood
  cells, and weaken pathogens cell membrane
  allowing water in so it will burst

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• 5) Antibodies made by B cells
• Attack pathogens by binding themselves to the
  pathogen to prevent them from attacking healthy
  cells
• Cause pathogens to clump, making it easier for
  phagocytes to engulf and destroy

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• 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 cant enter it- it cant reproduce!