3 lines of defense

• The body's defense system: the body defends you against anything that it does not recognize as being part of or belonging inside you
• Common target of the defense system are pathogens and cancer cells
• Pathogens include disease-causing bacteria, viruses, prions, protozoans, fungi, parasitic worms
• what are the common targets of the defense system?

  pathogens and cancer cells
• There are 3 strategies for defending against foreign organisms and molecules or cancer cells
• Three lines of defense include physical and chemical surface barriers, internal cellular and chemical defenses, immune response
• Physical and chemical surface barries are non-specific and keep the foreign organisms or molecules out of the body
• Internal cellular and chemical defenses are non-specific and attack any foreign organisms or molecules that have gotten past the surface barriers
• The immune response is specific and destroys specific targets and remembers them