The Immune System

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What it is…•The immune system enables an animal to avoid or limit any infections.

•The Immune System has 2 different defense systems– Innate and Acquired

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Innate Immunity

Barrier Defenses:• Skin- an outer covering

which provides a significant obstacle to invasion by the microbes that are present on the body.

• Mucous membranes- Form physical barriers that bar the entry of microorganisms and viruses

Internal Defenses:• Phagocytic cells(types of White

Blood Cells)- A cell that ingests microorganisms and foreign particles.

• Inflammatory response- the changes brought about by signaling molecules released upon injury or infection

• Natural killer(NK) cells- help recognize and eliminate certain diseased cells in vertebrates

Acquired(Adaptive) Immunity

• Humoral response

– Antibodies defend against

– Infection of body fluids

• Cell-mediated response

– Cytotoxic lymphocytes defend against infection in body cells

http://hplusmagazine.com/sites/default/files/images/articles/jan10/influenza-virus-antibodies.gif

Acquired Immunity Defends against infection of body cells and fluids

• Helper T Cells- makes CD₄- a response to nearly all antigens

• Cytotoxic T Cells-make CD₈- response to infected cells

• B Cells- generate antibody-secreting plasma cells- response to extracellular pathogens

• Active Immunization- vaccine which is a nonpathogenic form of a microbe

• Passive Immunity- provides immediate, short term protection

• Immune Rejection- certain vaccinations could be rejected due to persons blood type