Immunology

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Immunology

• Pasterik 2006

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Your immune system is designed to defend against
a constant barrage of viruses, bacteria, fungi,
toxins and parasites.
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You can see it in action when

• You get a cut, the opening provides entrance for
  bacteria and viruses
• When a mosquito bites you, the itchy bump is a
  sign of your immune system at work
• When you breathe, you take in thousands of germs,
  a cold or flu is an indication your immune system
  failed to stop one
• When you eat, you take in hundreds of microbes,
  some of them harmful, if your immune system fails
  to neutralize them, you could get food poisoning
• Allergies are signs that your immune system is
  working inappropriately, signalling defenses for
  harmless particles like dust, or cat dander
• When you get a blood transfusion or organ
  transplant, your immune system may work against
  the process by treating the transplant (or blood)
  as a harmful invader
• When you die, your immune system shuts down, all
  the things that bombard your body now have free
  access. Decomposition occurs in weeks as all
  these microbes consume your tissue
• Some diseases called Autoimmune Diseases occur as
  a direct result of the body's immune system not
  working properly. Example arthritis, Lupus

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The first Line of defense is the skin and mucous
membrane, which also lines the gastrointestinal
and respiratory passageways. The skin is tough
and the high acidity of the stomach acts as an
excellent disinfectant.
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The Lymph System

• Includes lymph nodes and lymph fluid.
• Lymph fluid is blood plasma (liquid that makes up
  the blood minus the red and white cells).
• Bacteria or other pathogens that enter the body
  find their way into this fluid, which is filtered
  through the lymph nodes.
• The lymph nodes then filter the fluid and remove
  these dangerous particles.
• These lymph nodes may swell when fighting an
  infection, hence you can feel those bulges at
  your neck when you're sick.

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The Thymus

• this organ lays between your breastbone and your
  heart. It is responsible for making T-cells.

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Spleen

• filters blood and removes any foreign particles
  and old blood cells in need of replacement.
• A person missing a spleen may get sick more often
  than one with a spleen.

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Bone Marrow

• Produces new blood cells, both red and white.
• The bone marrow produces all blood cells from
  STEM CELLS, which mature into different types of
  white blood cells.

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White Blood Cells - also known as
Leukocytes.Neutrophil - suicide bomber cells
that destroy cells infected by a
virus.Macrophages - consume pathogens.B Cells
- mature into plasma cells when
stimulated.Plasma Cells - produce antibodies
specific to an invader.Cytotoxic (Killer) T
Cells - bump into infected cells, poke holes in
them and destroy them.Helper T Cells - activate
Killer T cells and B cells.Phagocytes --
converge on the invaders and proceed to literally
"eat them up." Generally the phagocytes will
build up in one place, causing what we call puss
-- in order to eliminate the waste.
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Antigens and Antibodies

• Antigens are substances that trigger an immune
  response.
• Cells infected by viruses displace antigens on
  their surfaces.
• These antigens are recognized by other cells.

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• Antibodies are the bodies best defense against
  viruses.
• However, antibodies are specific in their
  actions, that is that a chickenpox antibody will
  only attack a chickenpox virus.
• Thus a particular virus stimulates the production
  of a particular antibody.

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The immune system activated
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