The Immune System Sneeze Sneeze

History of Identifying Pathogens Robert Koch ( ): “father of disease” -research focused on anthrax (bacteria). Koch’s Postulates: -rules for determining the cause of a disease or illness.

Infectious Diseases Pathogens: anything foreign that enters your body and can make you sick. Examples- bacteria, viruses, protists, fungi & non- harmful substances. Modes of Transmission: Air Food Water Person-to-person contact Animal bites (vector)

Human Diseases & Conditions Disease/ConditionPathogenMode of Transmission AIDSVirus (HIV)bodily fluids Common ColdCoronavirusair, physical contact MalariaPlasmodium falciparummosquitoes MeaslesParamyxovirusair, physical contact BotulismClostridium botulinumcontaminated food TetanusClostridium tetaniphysical contact Athlete’s FootTrichophyton rubrumphysical contact

First Line of Defense: Barriers Structures: Skin Oil (sebum) Mucous Membranes Tears Saliva Ear wax Hair/Cilia

Second line of Defense: NonSpecific Immunity NonSpecific Immunity includes: 1. Inflammatory Response 2. Temperature Response 3. Proteins 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- white blood cell that ingest and destroy pathogens. Phagocytes Examples: Neutrophils, Macrophages &Neutrophils Natural Killer CellsNatural Killer Cells – attack pathogen infected cells.

2. Temperature Response-Fever: sign body is responding to infection; suppresses growth and reproduction; promotes action of white blood cells. 3. Complement System- Proteins: 20 different proteins used to fight off pathogens, Exp.: Interferon- protein that inhibits reproduction of viruses.

Third Line of Defense: The Immune System & Response Immune System Structures 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, lymphocyteslymphocytes

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

The Immune Response: Let the Battle Begin! 1. Macrophage engulfs a pathogen. 2. Helper T-cells (lymphocyte) bind with macrophages to fight the pathogen and release specialized proteins (Interleukin). 3. Specialized proteins stimulate additional protein release that stimulate additional Helper T-cells and Cytotoxic T- cells.

A. Cell-Mediated Immune ResponseCell-Mediated Immune Response -Cytotoxic T-cells & Suppressor T-cells -destroy infected cells -shut down response after pathogens are cleared B. Humoral Immune ResponseHumoral 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 -Antibodies are stored for future use - Memory Cells (lymphocytes) are produced and remain in the body long term for future pathogen attacks.

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 initiates a primary immune response. Memory cells remain for future possible infections. -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)

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*

Type of CellFunction PhagocyteIngest and destroy pathogens. NeutrophilType of phagocyte, most abundant, attacks and destroys pathogens. MacrophageType of phagocyte, attacks and destroys pathogens. Natural Killer CellsAttack pathogen infected cells, cancerous cells, and virus infected cells. B CellsLymphocyte, made in bone marrow, changes in to Plasma cells. T cellsLymphocyte, made in bone marrow, sent to thymus for maturation. Helper T cellsLymphocyte, helps with the initial steps of the immune response by binding with a macrophage. Cytotoxic T cellsLymphocyte, destroys infected cells, cancer cells, and parasites. Suppressor T cellsLymphocyte, shuts down the immune response when all pathogens are gone. Plasma cellsLymphocyte, type of B cell that makes antibodies. Memory cellsLymphocyte, attacks pathogens later, not the first time.