Summary Chapter 9 Overview of the Body s Defense Mechanisms Defense mechanisms include Barriers to entry of pathogens disease producing microorganisms Skin Stomach acid Tears Vomiting Nonspecific defense mechanisms Phagocytosis inflammation Specific defense mechanisms Immune response Antibodies T cells Pathogens Cause Disease Disease causing agents include Living Organisms Bacteria unicellular prokaryotes Fungi unicellular and multicellular eukaryotes Parasites unicellular and multicellular eukaryotes Nonliving infectious particles Bacteria Single celled Living Organisms Viruses Prions Characteristics Prokaryotic Single celled Infections etc Generally treated with antibiotics Viruses Tiny Infectious Agents Extremely small much smaller than bacteria Living Open to debate Use a variety of resources for growth and reproduction Pneumonia tonsillitis tuberculosis botulism toxic shock syndrome syphilis Lyme disease Unable to reproduce outside of a host cell No metabolic activity Structure Contain DNA or RNA not both Nucleic acid is surrounded by a protein coat Diseases AIDS Hepatitis encephalitis rabies influenza colds warts chicken pox Prions Infectious Proteins Infectious proteins Normal brain proteins that are not folded correctly This mis folding becomes self propagating filling and disabling the cell with protein debris Resist cooking freezing drying Diseases Bovine spongiform encephalitis BSE mad cow disease Creutzfeldt Jakob disease CJD Transmissibility Mode of Transmission and Virulence Determine Health Risk Transmissibility How easily a pathogen is passed form person to person Mode of transmission Respiratory fecal oral body fluids How much damage is caused by the infection Lymphatic System Defends the Body Virulence Functions Maintenance of blood volume in cardiovascular system Transport of fats and fat soluble material from digestive system Filtration of foreign material to defend against infection Lymphatic System Components Lymphatic vessels transport lymph Lymph nodes cleanse the lymph The spleen cleanses the blood Thymus gland facilitates maturation of T lymphocytes Tonsils and adenoids protect the throat Keeping Pathogens Out The First Line of Defense Skin and effective deterrent Tears and saliva contain lysozyme antibacterial enzyme Ear wax entraps microorganisms Mucus entraps microorganisms Stomach highly acidic inhibits microorganisms Vagina Slightly acidic inhibits some microorganisms Vomiting urination and defecation remove microorganisms Resident Bacteria Outcompete pathogens Nonspecific Defenses Phagocytes Engulf Foreign Cells Phagocytic cells white blood cells that surround and engulf invading bacteria Neutrophils macrophages eosinophils Inflammation Redness warmth swelling pain Complement proteins lyse invading bacteria Interferons antiviral proteins Fever Response Natural killer cells a type of lymphocyte that attacks tumor cells and virus infected cells Specific Defense Mechanisms Third Line of defense The Immune Response Characteristics Recognizes and targets specific pathogens and foreign substances Has memory remembers initial exposure and responds more quickly and aggressively on subsequent exposures Able to distinguish between Self cells and foreign invaders Healthy cells and abnormal tumor cells Specific Defense Mechanisms Immune Response Targets Antigens Antigen any substance that triggers an immune response Usually protein of polysaccahride on outer surface of invading cell or virus MHC major histocompatibility complex proteins Self antigens that are on human cell surfaces enabling recognition of self Enable immune system to distinguish self from nonself Specific Defense Mechanisms Lymphocytes Are Central to Specific Defenses B lymphocytes Antibody mediated immunity Antibodies proteins made by B lymphocytes that bind with and neutralize specific antigens Active against viruses bacteria and soluble foreign molecules T lymphocytes Cell mediated immunity Directly attack foreign cells Coordinate the immune response Active against parasites viruses fungi intracellular bacteria cancer cells cells with nonself MHC Specific Defense Mechanisms B cells Antibody Mediated Immunity B cells activated when they recognize an antigen Divide into two cell types Memory Cells store information for future immune responses Plasma Cells actively secrete antibodies which will bind to antigen T Cells Cell Mediated Immunity T cells Originate from stem cells in the bone marrow Mature in the thymus Types of T cells CD4 T cells Helper T cells and Memory T cells CD8 T cells Cytotoxic T cells and Suppressor T cells APCs include Macrophages B cells Helper T cells Secrete cytokines which stimulate other immune system cells Play a key role in directing the immune response Are target of HIV infection T cells must be presented with antigen by antigen presenting cells APCs Directly attack and destroy abnormal tumor or viral infected cells and foreign cells Cytotoxic T cells Memory T cells Reactivate during later exposures Immune Memory Creates Immunity Primary immune response Occurs on first exposure to antigen Characteristics Lag time of 3 6 days fro antibody production Peak at 10 12 days Secondary immune response Occurs on second and subsequent exposure to antigen Characteristics Lag time in hours Peak in days Active immunization Also known as vaccination Passive immunization Medical Assistance in the War Against Pathogens Immunization A strategy for causing the body to develop immunity to a specific pathogen Intentionally expose individual to a form of the antigen that doesn t produce disease Administer protective antibodies to an individual Medical Assistance in the War Against Pathogens Monoclonal Antibodies Specific antibodies produced in the laboratory by a hybrid B cell clone Commercial applications of monoclonal antibodies Home pregnancy tests Prostate cancer screening test Diagnostic testing for hepatitis influenza HIV Medical Assistance in the War Against Pathogens Antibiotics Combat Bacteria Antibiotics kill bacteria or inhibit their growth Antibiotics are selectively toxic for bacteria by targeting features of bacterial cells that are different form eukaryotic cells Antibiotics are not effective against viruses Tissue Rejection A Medical Challenge system attacks the transplanted tissue organ To minimize risk of rejection Tissue rejection May occur following tissue or organ transplant if recipients immune Must match ABO and other blood group antigens and MHC antigens 75 MHC