Immune Immune SystemSystem

Immune SystemImmune SystemBody’s Body’s defensedefense against disease- against disease-causing organisms (causing organisms (pathogenspathogens))

Immune SystemImmune SystemFirstFirst line of defense:line of defense: – BarriersBarriers that keep pathogens from that keep pathogens from

entering the bodyentering the bodySkinSkinHair and mucus in Hair and mucus in nosenoseSneezing and Sneezing and coughingcoughingSalivaSalivaStomach Stomach acidsacids

Immune SystemImmune SystemSecondSecond line of defense:line of defense:– General defenseGeneral defense when body cells are when body cells are

damageddamagedInflammatoryInflammatory response—fluid and white response—fluid and white blood cells leak from blood vessels into blood cells leak from blood vessels into surrounding surrounding tissuetissue

Immune SystemImmune SystemSecond line of defense:Second line of defense:– General defense when body cells are damagedGeneral defense when body cells are damaged

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

– WhiteWhite blood cells— blood cells—attack invaders and eatattack invaders and eatthemthem

PhagocytePhagocyte—white —white blood cells that engulf blood cells that engulf pathogens and destroy pathogens and destroy them by breaking them by breaking them downthem down

Immune SystemImmune SystemSecond line of defense:Second line of defense:– General defense when body cells are damagedGeneral defense when body cells are damaged

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

– InterferonsInterferons—substances—substances produced by body cells produced by body cells when they are attacked by viruseswhen they are attacked by viruses

Interfere with the production of new Interfere with the production of new virusesviruses

Immune SystemImmune SystemThirdThird line of defense:line of defense:– Immune responseImmune response distinguishes distinguishes

between different kinds of pathogensbetween different kinds of pathogensMacrophagesMacrophages—white blood cells that patrol —white blood cells that patrol the body looking the body looking for invadersfor invaders

– They send They send off off chemicalchemical signals to signals to helper helper T-cellsT-cells

Immune SystemImmune SystemThirdThird line of defense:line of defense:– Immune responseImmune response

Helper T-cells have many Helper T-cells have many jobs:jobs:

– Make macrophages better able to Make macrophages better able to killkill– CallCall other cells in the immune system to the battle other cells in the immune system to the battle

This causes This causes feverfever, swelling and aches, swelling and achesSignsSigns that your body is working to fight a disease that your body is working to fight a disease

– Send chemicals that increase production of Send chemicals that increase production of B-cellsB-cells– Signal killer T-cells where the invader is Signal killer T-cells where the invader is hidinghiding

Immune SystemImmune SystemThird line of defense:Third line of defense:– Immune responseImmune response

B-cells produce B-cells produce antibodiesantibodies——– ProteinsProteins produced by the immune system which produced by the immune system which

destroy certain kinds of pathogensdestroy certain kinds of pathogens– AntigenAntigen—the —the

part of the part of the pathogen that pathogen that the antibody the antibody recognizes andrecognizes andbinds tobinds to

Preventing DiseasePreventing DiseaseNo cure for No cure for viralviral disease disease

Prevention is the keyPrevention is the key– VaccineVaccine—made from damaged particles —made from damaged particles

that can’t cause disease anymorethat can’t cause disease anymore

Preventing DiseasePreventing DiseaseFirst VaccineFirst Vaccine– 1798—Dr. Edward 1798—Dr. Edward JennerJenner

Developed a vaccine for Developed a vaccine for smallpox smallpox from the from the cowpox viruscowpox 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).