Defence mechanisms against
pathogenic diseases.
And other stuff.
Pathogens
Pathogens are bacteria and viruses that
cause disease.
Infection is a daily event. Sickness
however is not because not all infections
cause disease.
The human body is constantly exposed to
pathogens from the very moment of birth.
You probably contact many potential
pathogens every day.
The immune system is our
primary defense against
microorganisms that cause
disease, and consists of NonSpecific and Specific Defenses
against infections.
Non-Specific Defenses.
Non-Specific Defenses guard against
pathogens in general. Harmful or not.
These defenses are the first line of
protection (after the skin) against
pathogens in the body.
White Blood cells are a non-specific
defense.
Specific Defenses.
Specific defenses are put into action when
the Non-Specific Defenses fail.
These Defenses are attempts by the body
to fend of particular pathogens, usually
harmful ones.
They are the second line of defense. Well
duh!
Circulatory System.
 White Blood cells (lymphocytes) in the
circulatory System help the body fight off
pathogens, when an infection occurs your
body makes more white blood cells to fight
the infection.
There are two types of lymphocytes, B
and T. B produces anti-bodies while T
attacks pathogens directly.
The Lymphatic System.
 The lymphatic system is the taxi of the immune
system, it carries the white blood cells around to
all parts of the body.
 Lymph is the fluid that flows through the
lymphatic system. It carries the white blood cells.
 Lymph nodes are situated along the lymphatic
system and their job is to produce phagocytes
which engulf bacteria and poisonous
substances.
Different ways of acquiring Immunity.
 Active: When the body is
actively producing its own antibodies due to vaccination or
infection. The body will
continue to make the antibodies after the infection is
gone.
 Passive: When the body
receives anti-bodies from the
mothers placenta or when
injected, the anti-bodies
gradually disappear.
New Zealands Immunisation program.
 The NZ immunisation program is free for
everyone.
 Most of the immunisations are just dead or
weakened cultures of the disease.
 Sometimes this isn’t enough for some diseases
so actual anti-bodies for the disease are injected
into the body. (passive immunity)
 The injected anti-bodies don’t last very long and
are gradually broken down and destroyed.
Tetanus.
Tetanus is a bacteria which enters the
body through a wound.
Symptoms are Contraction of muscles
(which hurts), especially the jaw and neck
muscles.
Tetanus injections hurt. Lots.
Treating Tetanus.
 Sometimes Tetanus develops too quickly and
the body fails to create enough anti-bodies,
sooooooooooo, anti-bodies are injected into the
body instead (passive immunity).
 But other times the body creates its own antibodies to fight the disease.
 The dead and infected tissue must be removed.
 Antibiotics are part of the treatment.
A sick orange!!!
Your lovely
presenters:
 Michelle, Anna, Sarah and Soraya.
Incase you missed that it was,
Michle, Ana,
Saraoh and Sorya.
That’s Michelle, Anna, Sarah and
Soraya.