Bio 1005 Chapter 17 Immunity Silver

viruses alive or dead - pathogen or parasite or other viruses alive or dead - pathogen or parasite or other ? many say not alive BUT I disagree it has the best of all worlds nothing to do until it’s CM receptors finds a match and then reproduce using somebody else’s energy

no organelles, no plasma membrane, no metabolism, no reproduction BUT they have DNA or RNA and enzymes to take over a specific cell and use the cells nuclear material to make many, many, viruses

What does a virus have to do attach – penetrate – uncoat – replicate – assemble parts – release – attach – and on and on

fight infections 3 ways vaccines – antiviral drugs - immunity

vaccines – live, weak, dead drugs – inhibit vital steps in reproduction immunity – innate, adaptive, genetic

immunity innate uses the bodies systems, non specific or adaptive requires exposure, specific, memory cells

pathogen enters body – monocyte becomes macrophage macrophage kills pathogen - picks up pathogen antigens which are shown to T(thymus) and B(bones) cells which 1) kill and 2) makes antibodies pathogen enters body – WBC secrete cytokine antibodies which attach to pathogens and prevent pathogens attaching target cells infected cells secrete – cytokines – which stimulate immune cells to secrete more cytokines which stimulates immune response

lymphocytes – make natural killer cells (NK) which seek out infected cells and attach to a major histocompatibility class 1 membrane receptor on the infected cells membrane or on a macrophage infected cell is destroyed or it is stimulated to perform apoptosis programmed cell death

liver cells and macrophages continuously manufacture inactive complement proteins which circulate throughout the body complement proteins bind to pathogens especially those tagged by the immune system complement proteins rapidly coat the pathogen or lysis (breaks open) the pathogen

adaptive or acquired immunity is the result of exposure to a pathogen takes days or weeks to be fully functional B and T cells become immunocompetent (able to recognize the current pathogen) then go to spleen and lymph nodes and rest until needed (new exposure)

pathogen into body – T cell binds to antigen on pathogen - T releases cytokines – cause B to divide rapidly – and make plasma cells – which will make antibodies which will bind to – pathogens antigens - which stimulates the complement system – resulting in the pathogen not attaching, and destruction of the pathogen at the same time memory B cells are stored for further infection by that pathogen

Thelper and Tcytotoxic cells Th – stimulate macrophages and Th1 Tc – stimulate B to make antibodies & stimulates Th2 - identifies and destroys infected & cancer cells - stimulates NK cells and Th cells

lymphatic system blood minus RBC bathes all extracellular fluid spaces spleen, thymus, adenoids, tonsils, lymph nodes, lymph ducts, lymph vessels,

Spleen stores B, T, macrophages, dendritic cells, NK cells, APC cells bring antigens to stimulate immune response

lymph nodes store B, T, macrophages, dendritic, APC bring antigens to stimulate immune response

some parts of the body such as your mouth, throat, nose, GI lumen, and lungs, are constantly exposed to foreign invaders these areas are immune tolerant they use a localized immune system by Treg cells

they also use a MALT system mucosa associated lymph tissue which lines mucosal surfaces throughout the body APC deliver antigens to immune cells directly below the mucosal surface the activated T cells circulate throughout the body seeking and destroying that specific pathogen

in the 1940s with the discovery of antibiotics people saw a world free of infection but the pathogens have numerous ways to stop the immune system cell capsule, toxins, mutation rate, rapid reproduction rate,

hypersensitivity – allergy autoimmune – destroy self tissue immunodeficiency – HIV, many kinds of immunity defense