Transcript Unit 10 Chapter 39 Immunity from Disease

Unit 10
Chapter 39
Immunity from Disease
The Nature of Disease
Pathogens
 Disease producing agents, such as,
bacteria, viruses, protozoans, fungi &
other parasites
 Infectious disease
 Any disease caused by the presence of
pathogens in the body
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The Nature of Disease
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Koch’s postulates of 1884
(a procedure to establish the cause of a disease)
1) A pathogen must be found in the body of a sick
organism
2) The pathogen must be isolated & grown in the lab
to produce a culture
3) When the cultured pathogen is placed in a new
host, it should cause the same disease
4) The pathogen should be isolated from the new
host and shown to be the original pathogen
The Nature of Disease
Endemic disease
 Disease that are constantly present in a
population (ex: common cold)
 Epidemic
 When many people in a given area are
affected with the same disease at about
the same time (ex: influenza)
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The Nature of Disease
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Antibiotics
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Substances produced by microorganisms that,
in small amounts, will kill or inhibit the growth
& reproduction of other microorganisms
Ex: Penicillin, an antibiotic
produced by a fungus, has
been in use for over 50
years; many microorganisms
are now resistant to penicillin
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The Immune System
Innate Immunity
 Your body’s own built-in defense
system
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First (& best) line of defense:
– Unbroken skin
– Body secretions, such as
mucus, tears, sweat, & saliva
The Immune System
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Second line of defense is inflammatory
response:
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Fever= increased body
temperature slows or stops the
growth of pathogens
Phagocytes = white blood cells,
such as macrophages, that destroy
pathogens
Interferon = proteins that protect
cells from viruses
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The Immune System
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Third line of defense is cellular immunity:
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Lymphocytes are types of white blood cells
that defend the body against foreign
substances
T cells are lymphocytes that defend against
abnormal cells & pathogens inside livings
cells
B cells are lymphocytes that provide
immunity against antigens & pathogens in
the body fluids
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The Immune System
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Lymph
Tissue fluid (to bathe, nourish cells) after it
enters the lymph vessels that will return it to
the blood
Lymph nodes
Glands that filter pathogens from the lymph
before it returns to the bloodstream
The Immune System
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Acquired Immunity
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Defending against a specific pathogen by gradually
building up a resistance to it.
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Passive = acquired naturally when antibodies
are transferred from mother to unborn child
through the placenta
Active = acquired artificially
when induced by vaccines
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Nonspecific defense
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Cellular immunity
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