Fighting Diseases

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Fighting Diseases
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Causes of Disease

• many diseases are caused by microorganisms,
  called pathogens
• they enter the body (called an antigen) and
  either damage tissues or produce substances that
  toxic to the body
• the body combats disease through the immune system

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The Immune-System Response

• the human body have many defenses against
  infection
• They are categorized into THREE lines of defense
• External (integumentary system)
• Non-specific (Innate) Immunity
• Specific Immunity

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1st Line of Defense Integumentary System

• the first line of defense is an external or
  physical barrier
• the human skin, if unbroken, forms an almost
  impenetrable barrier against microorganisms
• cells in the nasal passages and pharynx secrete
  sticky mucus that traps microorganisms and
  digestive enzymes in the mucus can destroy most
  microorganisms

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2nd Line of Defense Non-specific (Innate)
Immunity

• if invaders get pass the 1st line of defense and
  enters the body, the 2nd line of defense, a
  complex network of organs, works to get rid of
  the infection

Lymphatic system
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2nd Line of Defense The Lymphatic System

• white blood cells (called leukocytes) seek out
  and destroy invaders and are produced in the
  lymph nodes
• Three types of defending leukocytes
• Macrophages (big eaters, pus) engulf antigens
• Neutrophils - engulf antigens
• Natural killer (NK) cells kill invaded cells

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Macrophage Big Eater

• fishing for bacterial with long, sticky
  cytoplasmic extensions

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Inflammatory Response

• Histamine release increases blood flow
• Increase capillary permeability
• Edema swelling, pressure on nerves pain
• Immune cells circulate better
• Elevated temperature fever, helps with attack
  against pathogens

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3rd Line of Defense Specific Immunity

• Lymphocytes (another class of leukocytes) can
  recognize antigens and direct an immune response

T lymphocyte (helper T cell)
B lymphocytes (B cell)
antigen
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3rd Line of Defense Specific Immunity

• B cells produce and display antibodies (Plasma
  B cells), and some also become memory B cells
• antibodies are protein molecules that protect the
  body from invaders by attaching to the surface of
  the invader which makes it more easily
  identifiable to macrophages
• antibodies are unique to each antigen form a
  response against antigens, the surface of an
  invader may have many different antigens

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• Helper T cells
• release cytokines that activate more B cells,
  Killer T cells, and macrophages
• Kill viruses with toxins
• After the infections is over
• - B cells and T cells die, except for memory B
  cells

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T-Killer cells a.k.a. cytotoxic T cells

• Match the template with the viral antigen and
  kill the virus with toxins also kill cancer
  cells

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Active Immunity

• lasting protection against pathogens through the
  production of antibodies
• can be acquired naturally, when a person recovers
  from an invaders and has produced antibodies
  against it OR
• artificially, by the injection of vaccines made
  of dead or weaken invaders, or even isolated
  antigens, the body will produce antibodies to
  provide immunity towards the pathogen

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Prevention of Disease Summary

• Proper sterilization and/or cleaning of
  instruments surfaces
• disinfectants (chemical that kill microorganisms
  on surfaces) E.g., bleach
• Proper use of antiseptics (chemicals that can be
  used on the skin)
• e.g. mouthwash, antibacterial soap
• Proper use of antibacterial medication
• Vaccinations (dead form of pathogen)
• Natural human immune response

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Lets see this all in action
The Immune Response

• http//highered.mcgraw-hill.com/classware/ala.do?i
  sbn0072965819alaidala_1032810showSelfStudyTree
  true

http//www.youtube.com/watch?vIWMJIMzsEMg
Why is it necessary to have so many different
types of cells in the immune system?
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Lets Act It Out!!!?