Download Unit 3 part 2 PPT

UNIT 3 PART 2: IMMUNE SYSTEM
• The blood is a liquid tissue that has three
major functions:
– Transportation of nutrients, hormones,
wastes, etc.
– Regulation of body
temperature, pH, and
water balance
– Protection from disease
and from excess loss of
blood by forming clots
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PATHOGENS
• Something foreign that enters
the body and causes disease
such as:
– Viruses (AIDS, chicken pox,
common cold)
– Bacteria (strep throat, E. coli)
– Fungi (athlete’s foot, ringworm)
– Parasites (tapeworm, leech,
malaria)
– Toxins (lead poisoning, carbon
monoxide)
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The Immune System
• The function of the
immune system is to
protect the body from
disease
• Recognizes, attacks,
destroys, and
remembers each kind
of pathogen
• Components: bone
marrow, WBCs,
lymph nodes, tonsils,
thymus, and spleen 8
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IMMUNITY
• The ability to fight infection through the
production of antibodies or the production of
phagocytic cells that kill foreign cells.
• It works because the body can distinguish
between itself and foreign substances or
“nonself” by recognizing cell markers.
• Lymphocytes (B cells and T cells) recognize
foreign antigens and either produce
antibodies or kill foreign cells. Each B or T cell
recognizes a different antigen.
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• Antigen
– A molecule on the
surface of a cell that
identifies that
particular cell. All cells
have many kinds of
antigens.
• Antibody
– Binds to the antigen
and helps destroy it
– Made by T and B cells
– Each one recognizes
a different antigen
Antigen
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Bellringer 1/4
• How does a vaccine
work?
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ACTIVE IMMUNITY
• You make your own
antibodies when exposed
to an antigen, like when
you get sick, or when you
get a vaccination. The
antigens used are dead or
weakened viruses or
bacteria. They trigger the
immune response without
making you sick.
• This type of immunity is
permanent.
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PASSIVE IMMUNITY
• Antibodies are given to
a person
– From the blood of
another person or
animal
– From your mother
during her last month of
pregnancy, or in
mother’s milk
• This type of immunity
is temporary.
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BLOOD GROUPS
• All human cells have antigens; that is how self
and nonself are recognized.
• There are 4 major blood groups that depend on
the presence or absence of 2 antigens on a
person’s RBCs.
• You are born
with
antibodies
against the
antigen that is
NOT present
on your
RBCs.
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Lab: Human Blood Groups
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What happens if you are given the
wrong blood type?
• If you are given a type that you have
antibodies for, then the blood will clump, clog
vessels, and cause kidney failure.
• Transplanted organs are also rejected
because they have nonself antigens and
your body makes antibodies against them.
• This effect can be lessened if the recipient
and donor are closely related and if the
recipient takes immunosuppressant drugs to
slow or stop the body’s immune response.
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ALLERGIES
• An allergic response is caused by
your immune system reacting to
something it thinks is harmful but
really isn’t, such as pollen, pet
dander, nuts, shellfish, or bee
stings.
• This causes special cells to
release a substance called
histamine which causes
sneezing and itchy, watery eyes.
• Severe allergic reactions can
cause swelling that closes off
airways and can cause death if
not treated immediately.
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