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Human Body Lesson 8
The Immune System: Specific and Non-Specific Responses to Pathogens
Standard 10a. Students know the role of the skin in providing nonspecific defenses
against infection.
Standard 10b. Students know the role of antibodies in the body’s response to
infection.
Vocabulary
1. __________________________: the ability of an organism to resist a particular
infection or toxin
2. _________________________ _________________________: a non-specific defense reaction
to tissue damage caused by injury or infection
3. _________________________: elevated body temperature
4. _________________________: proteins produced by virus-infected cells that help
other cells resist infection
5. ___________________________ _______________________: specific defenses that attack
specific disease-causing agents
6. _________________________: a substance that causes an immune response
7. ___________________-_________________________ __________________________: defense
against abnormal cells and pathogens living inside cells, provided by T-cells
8. _________________________ _________________________: defense against pathogens and
antigens in body fluids, provided by B-cells
9. _________________________: proteins that recognize and bind to antigens
10. _________________________: injection of a weakened form of a pathogen to
produce immunity
11. __________________________ _________________________: immunity that occurs after
exposure to a pathogen
12. _________________________ __________________________: the short-term immunity that
results from the introduction of antibodies from another person or animal
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What is the function of the immune system?
•
The immune system protects your body from
_________________________, preventing infections whenever possible
and fighting off infections that do occur.
•
Without your immune system, you would die from even the
tiniest _________________________ because you would have no way to fight them
off (unless you lived in a bubble that absolutely no pathogens could enter)
Non-Specific Defenses: The First Line of Defense
• Your body’s most important non-specific defense is the
_________________________. The skin acts as a barrier to pathogens
•
When the skin is broken, pathogens can enter your body and
_________________________
•
_________________________ is another non-specific defense. Pathogens get stuck in
the mucus in your nose and throat and cannot enter your cells
•
The _________________________ that line your nose and throat help
_________________________ pathogens _________________________ from the lungs.
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Non-Specific Defenses: The Second Line of Defense
• If pathogens do get past your skin, such as through a cut, the
_________________________ _________________________ is activated.
•
The inflammatory response is a ____________ -_________________________ defense
reaction to _________________________ _________________________ caused by injury or
_________________________.
•
Blood vessels near the wound _________________________ and white blood cells
exit the blood vessels to _________________________ (eat) the invaders. The
infected tissue may become _________________________, _________________________, and
_________________________.
Fever is a Non-Specific Defense
• The immune system also releases _________________________ that
_________________________ your body _________________________. When your
body temperature is higher than normal, you have a
_________________________.
•
Fevers can _________________________ some pathogens.
•
Fevers also increase your _________________________ _________________________,
which increases the speed of your blood flow, which allows white
_________________________ cells to get to the site of infection faster!
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Interferons are a Non-Specific Defense
•
When _________________________ enter the body,
sometimes the virus-infected cells produce
_________________________, a group of proteins
that help other cells resist infection.
•
Interferons got their name because they
_________________________ with a the ability of a
virus to replicate – they block the
_________________________ (translation) of viral
_________________________.
Specific Defenses
•
Specific defenses attack specific pathogens.
•
Any pathogen that triggers a specific immune
response is called an _________________________.
•
Both _________________________ and
_________________________ -_________________________
immunity are specific defenses
Humoral Immunity
•
When a pathogen invades the body, cells in your
bloodstream called ____-_________________________
recognize the pathogen and start dividing rapidly
•
Plasma cells are B-cells that produce
_________________________. Antibodies recognize and
_________________________ to specific pathogens.
Antibodies act as a _________________________ for
other cells of the immune system to destroy
the antigen they are attached to (either by
killing the cell with antibodies on it or by
“eating” the antibody-antigen complex)
•
After an infection, most _________________________
cells die and stop producing antibodies, but
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_________________________ B cells remain in your bloodstream. If the same
pathogen invades your body again, the memory B cells will start to divide,
antibodies will be produced, and you will be able to fight off the pathogen
much more quickly than the last time.
Antibody Structure
•
Antibodies are _________-shaped. At the ends of the Y, there are identical
_________________________ -_________________________ sites that are
_________________________ to only one antigen. For example, an
antibody to the chicken pox virus would not bind to the polio
virus.
Cell-Mediated Immunity
•
When viruses or pathogens get _________________________ living cells,
antibodies alone cannot destroy them.
•
During a cell-mediated immune response, cells in your blood
called _________________________ ____-_________________________ hunt down infected
cells of the body and kill them.
•
There are other kinds of T-cells, including helper T-cells, memory T-cells, and
suppressor T-cells
•
_________________________ T-cells activate _________________________ T-cells and help
them learn to _________________________ the cells that
are infected.
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Acquired Immunity
•
_________________________ immunity
occurs naturally in the body
_________________________ you have been
_________________________ to a
_________________________. It is your
body’s way of
“_________________________” the
pathogens it has seen before so it
can fight them off quickly if they
ever invade again.
Active Immunity
•
_________________________ immunity is
a type of acquired immunity that
occurs after you have an infection
OR after you are given a vaccine
•
Your body _________________________
memory T and B cells that will
fight off the pathogen in the future.
Passive Immunity
•
_________________________ immunity is when the body is _________________________
making antibodies or memory cells, but you are still immune from certain
pathogens.
•
Babies have passive immunity because antibodies pass
across the _________________________ during development and
are in breast milk.
•
Sometimes, people are given _________________________ or
infusions of _________________________ that can help them fight
off diseases.
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