Mr. Bombick 7th Grade Science Immune System Mr. Bombick 7th Grade Science

Immune System Definition Immune system protects the body from harmful viruses and organisms (bacteria to parasites). Immune system protects the body from foreign matter from molecules to microscopic and macroscopic materials.

Initial Lines of Defense Not true immune responses Skin acts as a protective barrier to foreign materials Respiratory tract clears foreign materials with nasal filtration and mucociliary movement helped by sneezing and coughing Digestive tract starts to kill foreign organisms with saliva and stomach acid.

Second Line of Defense White blood cells attack foreign organisms and bacteria Inflammatory response results as a way of “recruiting” more white blood cells Interferon is a substance that is released by some immune cells that prevent some viruses from replicating

Third Line of Defense Antibody production by immune cells Antibodies are made in response to an antigen (foreign proteins) found on a foreign substance or invading organism T (from thymus) and B (from bone marrow) cells involved in antibody production Certain T cells activate some B cells to produce antibodies Combination of the antibody and antigen begins various cellular processes to destroy the source of the antigen

Immunity Immunity is the bodies resistance to a disease causing organism or a harmful substance The two basic types of immunity are active immunity and passive immunity

Active Immunity Results when antibody production occurs in the same individual exposed to an antigen Vaccination is an example of active immunity Memory B cells can react to the specific antigen years after the vaccination (the memory B cells can initiate the production of a large amount of antibodies in a short period of time

Immune Disorders Allergies are the result of antibodies formed in response to various allergens (dust, feathers, fur, pollen, or types of foods) Histamine is produced in the allergic response (antihistamines help alleviate some of the symptoms) Severe allergic responses can result in anaphylactic shock

Immune Disorders (cont.) AIDS (Acquired Immune Deficiency Syndrome) occurs in some individuals exposed to HIV (Human Immunodeficiency Virus) In these individuals the virus attacks a type of T cell that results in decreased immune function Decreased immune function eventually leads to death