Immune SystemImmune System

Mr. BombickMr. Bombick

77thth Grade Science Grade Science

Immune System Immune System DefinitionDefinition

• Immune system protects the body Immune system protects the body from harmful viruses and from harmful viruses and organisms (bacteria to parasites).organisms (bacteria to parasites).

• Immune system protects the body Immune system protects the body from foreign matter from from foreign matter from molecules to microscopic and molecules to microscopic and macroscopic materials.macroscopic materials.

Initial Lines of Initial Lines of DefenseDefense

• Not true immune responsesNot true immune responses• Skin acts as a protective barrier to Skin acts as a protective barrier to

foreign materialsforeign materials• Respiratory tract clears foreign Respiratory tract clears foreign

materials with nasal filtration and materials with nasal filtration and mucociliary movement helped by mucociliary movement helped by sneezing and coughingsneezing and coughing

• Digestive tract starts to kill foreign Digestive tract starts to kill foreign organisms with saliva and stomach organisms with saliva and stomach acid.acid.

Second Line of Second Line of DefenseDefense

• White blood cells attack foreign White blood cells attack foreign organisms and bacteriaorganisms and bacteria

• Inflammatory response results as a Inflammatory response results as a way of “recruiting” more white blood way of “recruiting” more white blood cellscells

• Interferon is a substance that is Interferon is a substance that is released by some immune cells that released by some immune cells that prevent some viruses from replicatingprevent some viruses from replicating

Third Line of Third Line of DefenseDefense

• Antibody production by immune cellsAntibody production by immune cells• Antibodies are made in response to an Antibodies are made in response to an

antigen (foreign proteins) found on a antigen (foreign proteins) found on a foreign substance or invading organismforeign substance or invading organism

• T (from thymus) and B (from bone T (from thymus) and B (from bone marrow) cells involved in antibody marrow) cells involved in antibody productionproduction

• Certain T cells activate some B cells to Certain T cells activate some B cells to produce antibodiesproduce antibodies

• Combination of the antibody and antigen Combination of the antibody and antigen begins various cellular processes to begins various cellular processes to destroy the source of the antigendestroy the source of the antigen

ImmunityImmunity• Immunity is the bodies Immunity is the bodies

resistance to a disease causing resistance to a disease causing organism or a harmful organism or a harmful substancesubstance

• The two basic types of The two basic types of immunity are active immunity immunity are active immunity and passive immunityand passive immunity

Active ImmunityActive Immunity• Results when antibody Results when antibody

production occurs in the same production occurs in the same individual exposed to an antigenindividual exposed to an antigen

• Vaccination is an example of Vaccination is an example of active immunityactive immunity

• Memory B cells can react to the Memory B cells can react to the specific antigen years after the specific antigen years after the vaccination (the memory B cells vaccination (the memory B cells can initiate the production of a can initiate the production of a large amount of antibodies in a large amount of antibodies in a short period of timeshort period of time

Immune DisordersImmune Disorders• Allergies are the result of antibodies Allergies are the result of antibodies

formed in response to various formed in response to various allergens (dust, feathers, fur, allergens (dust, feathers, fur, pollen, or types of foods)pollen, or types of foods)

• Histamine is produced in the allergic Histamine is produced in the allergic response (antihistamines help response (antihistamines help alleviate some of the symptoms)alleviate some of the symptoms)

• Severe allergic responses can result Severe allergic responses can result in anaphylactic shockin anaphylactic shock

Immune Disorders Immune Disorders (cont.)(cont.)

• AIDS (Acquired Immune Deficiency AIDS (Acquired Immune Deficiency Syndrome) occurs in some Syndrome) occurs in some individuals exposed to HIV (Human individuals exposed to HIV (Human Immunodeficiency Virus)Immunodeficiency Virus)

• In these individuals the virus In these individuals the virus attacks a type of T cell that results attacks a type of T cell that results in decreased immune functionin decreased immune function

• Decreased immune function Decreased immune function eventually leads to death eventually leads to death