phagocytic leukocyte Fighting the Enemy Within Immune System

phagocytic leukocyte “Fighting the Enemy Within” Immune System AP Biology lymphocytes attacking cancer cell lymph system 2006 -2007

Avenues of attack § Points of entry digestive system u respiratory system u urogenital tract u break in skin u § Pathways for attack circulatory system u lymph system u Regents Biology

Why an immune system? § __________________ u u lots of organisms want you for lunch! we are a tasty vitamin-packed meal § cells are packages of macromolecules § no cell wall u __________________ § ___________ w HIV, flu, cold, measles, chicken pox, SARS § ___________ w pneumonia, meningitis, tuberculosis § ___________ w yeast § ___________ w amoeba, Lyme disease, malaria u __________________ Regents Biology What’s for lunch? !

How are invaders recognized? § __________________ u ____________________________________ § “self” vs. “invader” one of your own cells disease-causing virus disease-causing bacteria antigens say: “I belong here” antigens say: “I am an invader” Regents Biology

Lines of defense § ______________ u broad, external defense § “walls & moats” u ______________ § ______________ u broad, internal defense § “patrolling soldiers” u ______________ § ______________ u specific, acquired immunity § “elite trained units” u ______________ Regents Biology § B & T cells

1 st line: Physical Barriers § non-specific defense § external barrier u ___________________ § ____________________ w respiratory system w digestive system w urinary system w genitals Regents Biology Lining of trachea: ciliated cells & mucus secreting cells

1 st line: Chemical barriers on skin § Skin & mucus membrane secretions u __________ § p. H 3 -5 u __________ § p. H 2 u __________ § washing action u __________ § traps microbes u __________ § anti-bacterial = “lick your wounds” u anti-microbial proteins § lysozyme w digests bacterial cell walls Regents Biology

2 nd: Generalist, broad range patrols § Patrolling ____________ u _________________ § ___________________ w surface name tag u phagocyte cells § __________ § “big eaters” Regents Biology Macrophage “eating” bacteria

Lymph system Production of white blood cells & traps “foreign” invaders lymph vessels (intertwined amongst blood vessels) Regents Biology 2 nd “circulatory” system lymph node

Phagocytes macrophage bacteria white blood cells that eat macrophage Regents Biology yeast

Why do injuries swell? § Inflammation u injured cells release chemical signals Pin or splinter § histamines w increases blood flow w brings more white blood cells to fight bacteria w brings more red blood cells & clotting factors to repair Regents Biology Bacteria Blood clot Swelling Chemical alarm signals Phagocytes Blood vessel

Fever § When a local response is not enough u full body response to infection u raises body temperature u higher temperature helps in defense § slows growth of germs § helps macrophages § speeds up repair of tissues Regents Biology

3 rd line: Lymphocytes § Specific defense u responds to specific invaders § recognizes specific foreign antigens § ___________________________ w ___________________________ Regents Biology B cell

B cells & antibodies § ______________ white blood cells that attack invaders in blood u mature in Bone marrow u § Plasma B cells u __________________ § Memory B cells u __________________ u can make antibodies quickly the next time § protects you from getting disease more than once Regents Biology

Antibodies § Proteins made by B cells that tag invaders in the blood so macrophages can eat them u tag says “this is an invader” gotcha! u _________________ Y Y Y Y Y Regents Biology Y Y YY Y Y B cells releasing antibodies invading germs tagged with antibodies macrophage eating tagged invaders

Y release antibodies patrol blood forever Y Y “reserves” Y YY Y Y Y Y 10 to 17 days Y Y Regents Biology Y Y Y Y Y Y memory B cells Y Y Y Y Y recognition B cells Y Y YY Y B cells Y Y (foreign antigen) Y Y Y invader Y Y B cells immune response Y

Vaccinations § ____________________________________ u rapid response if future exposure u § Most successful against viral diseases Regents Biology

Jonas Salk § Developed first vaccine u against polio April 12, 1955 Regents Biology 1914 – 1995

Polio epidemics 1994: Americas polio free Regents Biology

Protecting you from disease § Vaccinations u advantage § don’t get illness § long term immunity w produce antibodies for life § works against many viruses & bacteria § IMPORTANT PROTECTION u disadvantage § not possible against all invaders antibodies pass from mother to Breastfeeding baby in breast milk u mother’s milk gives baby antibodies & keeps baby healthy Regents Biology

What if the attacker gets past the B cells in the blood & infects some of your cells? You need trained assassins to kill off these infected cells! T AP Biology Attack of the Killer T cells! 2006 -2007

T cells § T cells mature in Thymus § Helper T cells u sounds the alarm for rest of immune system § Killer T cells u _______________ § Memory T cells u remembers invader & reacts against it again quickly Where’s that? Regents Biology

Thymus Regents Biology

Attack of the Killer T cells § _________________ T cell binds to invaded cell u secretes perforating protein u § punctures cell membrane of infected cell § cell bursts Killer T cell Cell membrane Perforin punctures cell membrane Regents Biology Vesicle Cell membrane Invaded cell

Immune response invader skin Y Y Y Regents Biology Y Y Y Y invaders infect cells Y Y invaders in blood skin

Protecting you from disease § _______________ u advantage § kill bacteria that have successfully invaded you w make you well after being sick u disadvantage § use only after sick § only good against bacteria § possible development of resistance by bacteria (if don’t use correctly) § can get sick again Regents Biology

Immune system malfunctions § _____________ u immune system attacks own cells § lupus w antibodies attack many different body cells § rheumatoid arthritis w antibodies causing damage to cartilage & bone § diabetes w beta-islet cells of pancreas attacked & destroyed § multiple sclerosis w T cells attack myelin sheath of Regents Biology brain & spinal cord nerves

Immune system malfunctions § Allergies u __________________ § allergens w proteins on pollen w proteins from dust mites w proteins in animal saliva § body mistakenly thinks they are attackers Regents Biology

Diseases of the immune system § HIV: Human Immunodeficiency Virus _____________ u helper T cells can’t activate rest of immune system u § body doesn’t hear the alarm § AIDS: Acquired Immuno. Deficiency Syndrome __________________________ u death usually from other invading diseases or cancer u Regents Biology

How to protect yourself… Regents Biology

It’s safe to ask Questions! AP Biology 2006 -2007