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Published byLouisa Wilson Modified over 8 years ago
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THE IMMUNE SYSTEM The function of the immune system is to fight infection through the production of cells that fight off foreign substances
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DISEASE: ● Any change, other than injury, that disrupts the normal functions of the body.
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PATHOGEN ● Any disease causing agent ● Diseases caused by pathogens are called infectious disease.
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TYPES OF DISEASES: Some are produced by ● outside agents o Bacteria, fungus, virus ● Environmental Factors o Cigarette smoke, toxins ● Inherited o Hemophilia
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Agents of Disease: ● VIRUS : VIRUS o tiny particles that invade and replicate within living cells. o Attach to surface of cells and inject their genetic material (DNA) which takes over the cell Causes the common cold, influenza, chicken pox and warts.
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● single-celled organisms o Cause disease by Breaking down tissue of infected organism for food Releasing toxins that harm the body Tuberculosis, meningitis, botulism, anthrax Bacteria
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Protists ● any organism that is not a plant, animal or fungus o Cause numerous infectious diseases including malaria, dysentery and African sleeping sickness
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Worms ● Flatworms and roundworms o Ingested- infected food o Flatworms from streams Infection with Loa Loa is spread by biting mango flies
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Fungi Some can attack the skin causing ringworm and athletes foot
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How diseases are spread: ● Inherited ● Vectors – organisms that carry disease causing agents ● Sexually transmitted
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The Immune System ● the body’s main defense against pathogens ● “remembers” each type of pathogen that enters the body ● IMMUNITY: the body’s ability to destroy pathogens before they cause disease
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Fighting Infectious Diseases: ● Nonspecific defenses: do not discriminate between one threat and another. ● Specific Defenses attack particular disease causing agents
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Nonspecific Defense: First line of defense ● THE SKIN – the body’s most important line of defense ● Mucus, saliva, tears- contain enzymes to break down the cell walls of many bacteria ● Stomach acid – destroy pathogens that make it as far as your stomach
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Nonspecific Defense: Second line of defense ● INFLAMMATORY RESPONSE a non-specific defense reaction to tissue damage caused by injury or infection o The presence of pathogens triggers the production of millions of white blood cells to fight the infection.
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Inflammatory response
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Specific Defenses or Immune Response: The reaction of the body to particular pathogens ● ANTIGEN: substance that triggers an immune response.
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● proteins that recognize and bind to antigens. ● carried through the bloodstream to attack the pathogen causing the infection. Antibodies:
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T cells : ( a type of White Blood Cell ) provide defense against abnormal cells and pathogens ● Killer T cells track down and destroy bacteria, fungi, or foreign tissue that contains an antigen. ● Helper T cells produce memory cells that “remember” the antigen if it enters the body again.
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Killer T Cells
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VACCINATIONS ● A weakened form of a pathogen to produce immunity ● Stimulates the immune system to create cells that are ready to produce specific types of antibodies
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Immune System Disorders: ● ALLERGIES : an overreaction of the immune system to an allergen such as pollen, dust, mold or bee stings. ALLERGIES o Inflammatory response o Releases histamines that increase flow of blood and fluids to the infected area.
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Autoimmune Diseases: ● When the immune system makes a mistake and attacks the body’s own cells. o Type 1 diabetes, multiple sclerosis, rheumatoid arthritis
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AIDSAIDS: An Immunodeficiency Disease ●AIDS – Acquired Immune Deficiency Syndrome. ●HIV – Human Immunodeficiency Virus o destroys T cells so the body does not have the ability to fight off infections infection that.
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Transmission of HIV ● Sex with an infected person ● Shared needles with an infected person ● Contact with body fluids of an infected person ● Infected mother to child
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Prevention of HIV ● Safe sex ● Don’t use drugs ● Protect yourself from blood CURE for HIV ● No cure ● The virus mutates. It is drug resistant ● Treatments extend the quality & length of an infected persons life
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