Transcript How does the immune system protect the body against disease?

TOPIC: Immunity
AIM: How does the
immune system protect
the body against
disease?
Topic: Immunity
Aim: How does the immune
system protect the body against
disease?
Do Now:
What causes strep throat?
Strep throat is a
contagious disease
caused by infection
with group A
streptococci bacteria.
The symptoms of
strep throat include
sore throat, fever and
stomach pain, along
with red and swollen
tonsils.
Immune
system
• Protects the body
against disease
What is a • Materials that cause
pathogen? disease (germs)
• Microorganisms
• Bacteria, viruses,
parasites, fungi…
Immune • How the body
recognizes
and
Response
defends itself from
pathogens
Antigen • Any substance
that starts an
immune response
• It can be:
• Pathogens (germs)
• Other materials
(dust, food…)
The Body’s Lines of
Defense
Immune
System
Pathogen
Your immune system patrols and protects
your body from harmful invaders. If your
immune system finds an invader, it takes
care of the problem.
st
1
line • Physical barriers 
• keep pathogens out of
the body
• skin,
• mucus,
• cilia,
• sweat,
• tears,
• saliva,
• digestive enzymes
•
1.
Inflammatory
response:
2nd
• WBC’s destroy pathogens
line
• 2. Interferons =
• proteins that help other
cells from being attacked by
viruses
Antibodies • Proteins that
(3rd line)
help destroy
pathogens
• Made bc of an
immune response
• Attach to antigen & slow it
down so WBC’s can destroy
them
How are • 2 types of WBC’s
antibodies • T cells tell B cells to
make antibodies
made?
1. Pathogen enters the body
2. Inflammatory response occurs
(WBC’s kill germs) OR infection occurs.
3. If infection occurs, the body's immune
system produces antibodies and white
blood cells to attack the pathogens.
4. Antibodies attach themselves to the pathogens,
slowing them down and making it easier for the
white blood cells to identify them.
5. White blood cells attack and destroy
the pathogens.
• 1. Infectious =
2
types of • pathogens spread to
another person
disease
• Ex: cold, flu, AIDS
• 2. Noninfectious = cannot be
spread
• (not caused by pathogen)
• Ex: Diabetes, cancer
AIDS
• Acquired Immune
Deficiency
Syndrome
• Infectious
disease
• Caused by HIV (Human
immunodeficiency virus)
Damages immune system by
destroying T cells
(body can’t fight off pathogens)
How is
HIV
transmitted?
1. Contact with
infected blood
2. Sharing
intravenous
needles
3. Sexual contact
4. Motherfetus
Allergies • An immune response or
reaction to substances
you are allergic
(sensitive) to
• Allergen = what you are
allergic to
• (pollen, dust, etc)
• Histamines produced
(chemicals released by cells that
cause symptoms)
Review:
1. What is a pathogen?
2. Explain what makes up your body’s first
line of defense.
3. How are antibodies produced?
4. How are infectious diseases different
from noninfectious diseases?
5. How does HIV affect the body?
6. What is an allergy?