The Immune System

Disease Transmission Robert Koch… “father of disease” -research focused on anthrax -Koch’s Postulates: rules for determining the cause of a disease or illness.

Human Diseases and How They Are Transmitted AIDS HIV Intercourse, contaminated syringes Common Cold many viruses air, person to person Malaria protozoan parasites mosquitoes Measles paramyxovirus air, person to person Botulism Clostridium botulinum contaminated food

Infectious Diseases -Pathogens – foreign particles Ex. Viruses + bacteria -Multiply in the body to cause infection -Come into contact with the body by: Air Food Water Person-to-person contact Animal bites

NonSpecific Defenses...First Line of Defense Skin – prevents entry Oil – traps and kills invaders Mucous Membranes – epithelial tissue that protect the interior surfaces of the body. Tears Saliva Ear wax Hair/Cilia

Second line of Defense: If a pathogen penetrates the first line of defense... 1. Inflammatory Response: series of reactions that suppress infection and speed recovery. a. Histamine released (Increases blood flow to site of injury/infection; can cause redness, swelling, warmth, and pain) b. Phagocytes – type of white blood cell. Neutrophils & Macrophages – attack pathogens Natural Killer Cells – attack pathogen infected cells. 2. Complement System – using proteins to fight off pathogens 3. Interferon - protein that inhibits reproduction of viruses 4. Fever - sign body is responding to infection; suppresses growth and reproduction; promotes action of white blood cells.

2. Thymus – gland in the chest 3. Lymph & Lymph Nodes The 3rd Line of Defense: Specific Defenses against a specific pathogen. Immune System – cells and tissues of your body that recognize and fight off pathogens. 1. Bone Marrow -Produces white blood cells lymphocytes -Two types: B cells & T cells 2. Thymus – gland in the chest -Place of maturation of T-cells 3. Lymph & Lymph Nodes -Filter pathogens, lymphocytes

-Contain lymphocytes which are important for antibody production. 4. Spleen -Filters pathogens from blood 5. Tonsils & Adenoids -Contain lymphocytes which are important for antibody production.

The Immune Response..two pronged attack! The Immune Response begins with the recognition of an Antigen (pathogen). -differing response based upon surface proteins on the antigen. -Begin with helper T-cells (lymphocyte) binding with macrophages to fight pathogens.

1. Cell-Mediated Immune Response -Cytotoxic T-cells & suppressor T-cells -destroy infected cells -shut down response after pathogens are cleared 2. Humoral Immune Response -B cells change into plasma cells and produce antibodies. Antibodies – chemicals that binds to antigen to disable the pathogen (block reproduction). -Antigen specific -Stores antibodies for the future use

Primary & Secondary Immune Responses Some B cells turn into memory cells Lymphocytes that will not respond the 1st time they meet an antigen, but will recognize and attack with later infections Explains why you get most diseases only once Primary Immune Response First time the body encounters an antigen Memory cells produced for that specific antigen Secondary Immune Response Later infection by the same pathogen Memory cells respond faster and stronger Exception: Cold and Flu viruses

Immunity & Vaccination 1. Immunity-the ability to resist an infectious disease Memory cells Vaccinations 2. Vaccine-solution that contains a dead or weakened pathogen Body produces primary immune response Booster shots

Problems of the Immune System: Allergies Asthma Autoimmune Diseases- immune system attacks your own body cells. (lupus, MS, type I diabetes, rheumatoid arthritis)

*PLAY DISCOVERYEDUCATION VIDEO* HIV and AIDS AIDS- Acquired Immunodeficiency Syndrome The immune system loses its ability to fight off pathogens and cancers AIDS results from infection by HIV HIV-Human Immunodeficiency Virus Destroys Helper T cellscripples the immune systemleads to AIDS Opportunistic Infections-illnesses caused by pathogens that produce disease in people with weakened immune systems Usually these pathogens don’t create problems in healthy people HIV does NOT cause death, but AIDS is fatal Death caused by weakened immune system’s inability to fight opportunistic infections and cancers HIV is transmitted by body fluids and contaminated needles *PLAY DISCOVERYEDUCATION VIDEO*

Summary of Cell Types: