Transcript your body`s defense against infection lesson 2

BELL WORK
Write about the last time you were
sick. How did you feel and what
happened?
COMMUNICABLE DISEASES
THE BODY’S DEFENSES AGAINST INFECTION
OBJECTIVES
 name the body’s first line of defense against
pathogens.
 describe how the immune system functions.
 explain how antibodies protect the body.
 practice behaviors that keep your immune
system healthy.
5 MAJOR BARRIERS
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TEARS
SALIVA
SKIN
MUCOUS MEMBRANES
STOMACH ACID
YOUR BODY DEFENDS ITSELF
If a pathogen gets past one of
the five major barriers, your
body’s immune system takes
over.
immune system A combination
of body defenses made up of
the cells, tissues, and
organs that fight off pathogens
and disease
YOUR BODY DEFENDS ITSELF
Your immune system’s two main responses are
the nonspecific response and the specific
response.
Together, these responses provide immunity.
immunity Your body’s ability to resist germs
that cause a particular disease
NONSPECIFIC IMMUNE RESPONSE
The nonspecific response begins
with inflammation.
inflammation The body’s
response to injury or disease,
resulting in a condition of
swelling, pain, heat, and redness
NONSPECIFIC IMMUNE RESPONSE
With inflammation, the body starts producing a
protein called interferon to stimulate the body’s
immune system.
SPECIFIC IMMUNE RESPONSE
Each specific response is
customized to attach a
particular pathogen and its
toxins.
Our immune system can
“recognize” pathogens it has
already battled.
THE LYMPHATIC SYSTEM
The fluid circulation in
the lymphatic system is
called lymph (LIMF).
lymphatic system A
secondary circulatory
system that helps the
body fight pathogens
and maintains its fluid
balance
THE LYMPHATIC SYSTEM
The two types of lymphocytes
are B cells and T cells.
lymphocytes The white blood
cells in the lymphatic system
B cells form in the bone marrow.
T cells develop in the thymus
gland.
THE LYMPHATIC SYSTEM
Macrophages are found in the lymph.
Their purpose is to attach themselves to
invading pathogens and destroy them.
ANTIBODIES AND ANTIGENS
Lymphocytes react to antigens.
antigen Any substance released by invading
pathogens
ANTIBODIES AND ANTIGENS
The immune system responds to antigens by
producing antibodies.
antibodies Proteins that attach to antigens,
keeping them from harming the body
ANTIBODIES AND ANTIGENS
• B cells produce a specific antibody for each
specific antigen.
• T cells either stimulate the production of B
cells or attack pathogens directly.
• The two types of T cells are helper cells and
killer cells.
IMMUNITY
Everyone is born with a natural
immunity.
Immunity also develops when a
vaccine is used.
vaccine A preparation of dead
or weakened pathogens that
causes the immune
system to provide antibodies
IMMUNITY
To keep your body healthy, it is important to
keep vaccinations current.
Vaccines protect not only you but those around
you.