immune system

how the immune system works

1st and 2nd line defenses

1st line: dead skin barrier, mucus, saliva, tears contain lysozyme (enzyme that breaks down bacterial cell walls), acidic oil and sweat kills many bacteria

2nd line: inflammatory response, increased white blood cell production, blood vessel expansion, infectedtissue becomes swollen, painful, fever (heat kills pathogens)

recognizing the pathogen

innate immunity- a subsystem of the overall immune system that comprises the cells and mechanisms that defend the host from infection by other organisms. antigens will be produced when a recognized pathogen invades.