2. THE THREE LINES
OF
DEFENCE

3. There are “Three lines of Defense” that all
contribute to the Immune System ,each an
important part in the destruction of Pathogens
(Pathogens are any foreign substance found in the body that causes an
Immune Response)

4. First Line
of
Defense

5. Skin
Thick layers of Skin make
the penetration of
Pathogens nearly Impossible

6. The First Line of Defense
Sweat and Oil on your skin kill most Pathogens they come in
contact with due to the fact that your Sweat is acidic.

7. Mucus Membranes

8. Thick walls of Mucus line your Nose, Throat , and
Stomach. Mucus acts as a kind of glue that traps
any Pathogens that happen to be going by . The
Cilia (little hairs) then move the Pathogen filled
Mucus out of the body

12. Secretion
Mucus
Tears
Saliva
Sweat

13. The various secretions push
out pathogens and also
contains a chemical called
Lysozyme that breaks
through the cell walls of
Bacteria therefore killing
them.

14. Mucus

15. Tears

16. Saliva

17. Sweat

18. Second line
of
Defense

19. Innate Immune
Response
There are four important non-
specific (Innate) defenses that come
into action once a pathogen has
entered the body.
Inflammatory Response
Temperature Response
Proteins
White Blood Cells

20. The Inflammatory
Response
A series of events that
repress infection and speed
healing through dilation of
blood vessels.

21. Histamines dilate blood
vessels and bring white
blood cells to the area of
infection thus causing
Inflammation

22. Swelling ,Redness, and Puss
may also occur
(Puss—A build up of millions of dead
white blood cells )

23. Temperature
Response
To fight pathogens the body will
raise its temperature a couple
degrees above normal to try and
kill them.

24. Fever helps to combat bacteria
due to the fact that Pathogens
cannot survive high
temperatures.

25. Proteins
A variety of proteins
provide a non-specific
defense from Pathogens

26. Interferon is a protein release
by cells infected with a virus.
(Its causes nearby cells to create an
enzyme that prevents Viruses from
making proteins and RNA)

27. White Blood Cells
(Phagocytes)
Neutrophils , macrophages and
natural killer cells wait within
tissue for pathogens to
annihilate.

28. Neutrophils overwhelm and
destroy pathogens by sacrificing
themselves for wellbeing of the
rest of the body

31. Macrophages consume and
kill pathogens as well as
clear the body of dead cells
and debris.

33. Natural killer cells puncture
the cell membranes of
pathogens, allowing liquid to
rush in and make the cell
burst

35. The Third Line
of
Defense

36. Acquired Immune
Response
The 3rd line of defense is Called “The
Acquired Immune Response” is a specific
Immune response unlike the first and
second line of defense. Its is an Immune
response that you gain by being infected
with pathogens or virus’ and combating
them.

37. Helper T-Cells activate
both cytotoxic T cells and
B cells

38. Helper T-Cell

39. The helper T Cells
recognize Virus’s that
would otherwise go un-
noticed. It then alerts the
B-Cells. The B cells first
analyze the virus then
they construct a antibody
that is specifically for that
one virus.

41. After the Virus is smothered
in antibodies and cannot
infect anything other cells
the killer t cells are called to
the seen to dispose of the
incapacitated virus and kill
the infected cells.

44. Armed Memory B-Cell

45. Antibodies are Immune
System proteins that
destroy pathogens

48. The
End!!!
By:Johnathan Baekgaard