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Fighting Diseases

Fighting Diseases. 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. The Immune-System Response.

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Fighting Diseases

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  1. Fighting Diseases

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. Macrophage – “Big Eater” • “fishing” for bacterial with long, sticky cytoplasmic extensions

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. Let’s see this all in action http://highered.mcgraw-hill.com/classware/ala.do?isbn=0072965819&alaid=ala_1032810&showSelfStudyTree=true The Immune Response http://www.youtube.com/watch?v=IWMJIMzsEMg Why is it necessary to have so many different types of cells in the immune system?

  16. Let’s Act It Out!!!

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