Immune SystemThe cells and tissues that recognize and

attack foreign substances in the body

Causes of DiseaseNoninfectious Disease: Cannot be spread

from one individual to anotherInfectious Disease: Caused by a pathogen

and can be spread from one individual to another

Pathogen: A microorganism, a virus, or a protein that causes a disease

Pathways to PathogensAirContaminated ObjectsPerson to personAnimalsFood and Water

Putting Pathogens in their placePasteurizationVaccines & ImmunityAntibiotics

Immunity: The ability to resist or to recover from an infectious disease

Cells of the Immune SystemMacrophages: Engulfs pathogens and other

materialsT cell: Coordinates the immune system and

attacks many infected cellsB cell: A white blood cell that makes

antibodiesAntibody: A protein made by B cells that

binds to a specific antigen.Antigen: Substances that stimulate an

immune response

Memory B CellsA B cell that responds to an antigen more

strongly when the body is reinfected with an antigen than it does during its first encounter with the antigen.

FeversFevers of a couple degrees help immune cells

reproduce and help your body fight infections

Fevers more than a couple degrees can be dangerous however.

Challenges to the Immune SystemAllergies (When the immune system overreacts to

antigens that are not dangerous to the body.Autoimmune diseases (A disease in which the

immune system attacks the organism’s own cells; ex: rheumatoid arthritis, diabetes, multiple sclerosis)

Cancer (A disease in which the cells begin dividing at an uncontrolled rate and become invasive)

AIDS (acquired immune deficiency syndrome); When HIV (human immunodeficiency virus) kills helper T cells. People with AIDS rarely die from AIDS itself, rather from other diseases they cant fight off)