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The Body’s Army
THE IMMUNE SYSTEM
INFECTIOUS DISEASES
 Viruses
 Human body is the only thing that can defeat a
virus since it is not a living thing
 Some can be prevented with vaccinations
 Examples: flu, common cold, smallpox, chicken
pox, AIDS, viral pneumonia
 http://www.youtube.com/watch?v=Rpj0emEGShQ
INFECTIOUS DISEASES
 Bacteria
 Pathogen – organism that causes disease (not all
bacteria are pathogenic to humans)
 They affect the body by
 Producing toxins or poisons
 Killing or damaging cells in certain parts of the body
 Most can be killed by medicines such as antibiotics
since they are living organisms
 Examples: strep throat, tetanus, pneumonia, food
poisoning
 http://www.youtube.com/watch?v=tqOVYpkZ0qs&NR=1
INFECTIOUS DISEASES
 Protists
 Act like parasites as they move throughout a host
 Disease-causing protists are usually spread by
contaminated water and food or by bites or
contact with some animal
 Examples: malaria, African sleeping sickness,
amoebic dysentery

http://www.bing.com/videos/watch/video/malarialifecycle/c1f4276d8612c38f6f63c1f4276d8612c38f6f63764068627082?q=malaria+life+cycle&FROM=LKVR5&GT1=LKVR5&FORM=LKVR
INFECTIOUS DISEASES
 Fungus
 Occur when people come in contact with the
spores of the fungus
 Very difficult to treat and often will recur
 Examples: ringworm, athlete's foot, lung
infections
 Penicillin is a fungus that is used to fight bacterial
infections
INFECTIOUS DISEASES
 Parasites
 Parasite – organism that lives off of and harms
another organism
 Host – the organism that a parasite infects
 Enter the body through contaminated water or
food, direct contact with the parasite,
undercooked food, food that has not been
properly cleaned and cuts in the skin
 Examples: elephantitis, bedbug bites,
tapeworms, trichinosis
INFECTIOUS DISEASES
 Parasites
 http://www.youtube.com/watch?v=AMqtC8jXvTw
&feature=BFa&list=SP85C902E5A8A1D956&inde
x=24
 http://www.youtube.com/watch?v=90exkFR2iSM
&feature=relmfu
 http://www.youtube.com/watch?v=AdR2U0yPLc&NR=1
 http://www.youtube.com/watch?v=BqjMYEfViKA
&feature=related
IMMUNE SYSTEM
http://kidshealth.org/kid/htbw/_bfs_ISmoviesource.html
 Complex system of organs, tissues and
specialized cells whose primary function is to
defend the body from infectious organisms
and other foreign invaders
 Uses the skin, circulatory system, respiratory
system and digestive system to help protect
the body from pathogens
BODY’S DEFENSE SYSTEMS
 First Line of Defense – Barriers
 Skin – forms a physical and chemical barrier
 Breathing passages – mucus and cilia trap
potential pathogens and a sneeze or cough can
remove pathogens
 Mouth – enzymes in saliva destroy some
pathogens
 Stomach – acid in stomach destroys many
pathogens
 Pancreas and liver release enzymes that can
destroy pathogens
BODY’S DEFENSE SYSTEMS
 Second Line of Defense – Inflammatory
Response
 http://www.dnatube.com/video/342/Inflammatory-Response
 Caused by capillaries in an area enlarge to allow
more blood to flood the area.
 Fluid and phagocytes leak into the surrounding
tissue. Phagocytes are white blood cells that
engulf (eat) and destroy pathogens.
 The affected area becomes red, swollen and
warm.
BODY’S DEFENSE SYSTEMS
 Third Line of Defense – Immune Response
 http://www.youtube.com/watch?v=1tBOmG0QMbA
 Occurs when the pathogen gets in the circulatory
systems
 Fever – a rise in body temperature due to the
inability of the white blood cells to completely
destroy a pathogen
 Antigen – molecules that the immune system
recognizes as not part of the body (foreign)
BODY’S DEFENSE SYSTEMS
 Third Line of Defense – Immune Response
 Types of White Blood Cells (WBC)
 Phagocytes – engulf and destroy pathogens
 Lymphocytes – WBC that target specific pathogens
 T cells – identifies pathogens by recognizing their
antigens
 B cells – produce antibodies that bind to a pathogen’s
antigens and mark it for destruction.
IMMUNITY
 The body’s ability to destroy pathogens
before they can cause disease.
THE IMMUNE SYSTEM
 It’s a war that is fought daily for your life!