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Immune System


Immune System Body’s defense against disease-causing organisms (pathogens)


Immune System First line of defense:

– Barriers that keep pathogens from entering the body Skin Hair and mucus in nose Sneezing and coughing Saliva Stomach acids


Immune System Second line of defense:

– General defense when body cells are damaged

Inflammatory response—fluid and white blood cells leak from blood vessels into surrounding tissue


Immune System Second line of defense:

– General defense when body cells are damaged

Inflammatory response—fluid and white blood cells leak from blood vessels into surrounding tissue – White blood cells— attack invaders and eat them Phagocyte—white blood cells that engulf pathogens and destroy them by breaking them down


Immune System Second line of defense:

– General defense when body cells are damaged

Inflammatory response—fluid and white blood cells leak from blood vessels into surrounding tissue – Interferons—substances produced by body cells when they are attacked by viruses Interfere with the production of new viruses


Immune System Third line of defense:

– Immune response distinguishes between different kinds of pathogens

Macrophages—white blood cells that patrol the body looking for invaders – They send off chemical signals to helper T-cells


Immune System Third line of defense: – Immune response

Helper T-cells have many jobs:

– Make macrophages better able to kill – Call other cells in the immune system to the battle This causes fever, swelling and aches Signs that your body is working to fight a disease – Send chemicals that increase production of B-cells – Signal killer T-cells where the invader is hiding


Immune System Third line of defense: – Immune response

B-cells produce antibodies—

– Proteins produced by the immune system which destroy certain kinds of pathogens – Antigen—the part of the pathogen that the antibody recognizes and binds to


Preventing Disease No cure for viral disease Prevention is the key

– Vaccine—made from damaged particles that can’t cause disease anymore


Preventing Disease First Vaccine

– 1798—Dr. Edward Jenner

Developed a vaccine for smallpox from the cowpox virus

The arm of Sarah Nelmes, a dairy maid, who had contracted cowpox. Jenner used material from her arm to vaccinate an eight year old boy, James Phipps (1798).


Immune System