The Immune System  Repels disease-causing organisms  Removes dead/damaged cells  Destroys malfunctioning cells

Non-Infectious Diseases…  Are NOT caused by microorganisms (germs like bacteria and viruses)  Such as cancer and diabetes mellitus

Infectious Diseases…  Are transmitted (carried) among people by disease-causing microorganisms.  Bacteria, viruses  Can be contagious

Immunity…  The resistance to a disease- causing organism or a harmful substance.

Active Immunity…  The body produces the necessary antibodies either because a person caught a disease or a person is vaccinated against it.

Passive Immunity…  Antibodies come from a source other than yourself.  (a mother to an unborn baby)

Vaccines are effective because…  The weakened or dead viruses do not make you sick, but they stimulate your body to make antibodies against them.  Once the antibodies are made the 1 st time, the body is ready to make them again on short notice if the same kind of invader returns.

A Booster Shot…  Is a vaccine (shot) that increases the production of antibodies in the body.

1 st Line of Defense  Skin, mucus, cilia, saliva  Coughing, sneezing, tears, sweat, stomach acid

The Respiratory System…  Is defended by mucus and cilia  Organisms get trapped in the mucus and are swept out of air passages by the cilia

2 nd Line of Defense…The Inflammatory Response  1. Disease causing organism enters skin.  2. Body increases blood supply to the affected area  3. WBC leave blood vessels and move into tissues, where they gobble up invading organisms  “Wheel and Flare”

Antibodies…  Proteins made by the immune system  Responsible for destroying harmful invaders  3 rd line of defense  Are SPECIFIC for certain antigens

Antigens…  The invading organism or substance that triggers the action of an antibody  “producer of antibodies”

The shape of an antibody…  Changes from a “T” to a “Y”  The two “arms” of the “Y” attach and bind to the antigen  This prevents invaders from attaching to our cells

B cells and T cells…  Are both special white blood cells  T cells alert B cells to make antibodies

Cancer is…  A disease in which cells multiply uncontrollably, destroying healthy tissue.

AIDS  A disease caused by a virus that attacks, hides in, and destroys helper T cells.  Helper T cells signal the presence of a disease-causing organism.  Without helper T cells, the immune system is crippled and diseases that normally would be destroyed are free to attack the body.

Allergies…  Result when the immune system is sensitive to certain substances.

Allergens…  Substances that cause an allergic reaction.  Dust, feathers, animal hair (dander), pollen, foods

Diabetes Mellitus is…  A disease that occurs when the body either makes too little insulin or is not able to use the insulin that it does make.