“Fighting the Enemy Within” http://www.youtube.com/watch?v=lrYlZJiuf18 phagocytic leukocyte Immune System lymphocytes attacking cancer cell lymph system 2006-2007

Avenues of attack Points of entry Pathways for attack digestive system – mouth – saliva/acid respiratory system – nose – hairs/mucus urinary system – urethra (shorter in females) genitals break in skin – cut eyes Pathways for attack circulatory system lymph system = How pathogens move around your body

Why do we need an immune system? Attack from the outside & inside cells are packages of proteins, carbohydrates & fats no cell wall – plasma membrane – semi permeable organisms must defend themselves against (pathogens) invaders viruses – NOT LIVING ( http://www.youtube.com/watch?v=Rpj0emEGShQ ) HIV, flu, cold, measles, chicken pox, SARS bacteria pneumonia, meningitis, tuberculosis, strep throat fungi yeast, ringworm, athlete’s foot protists amoeba (disentary) , Lyme disease, malaria cancer cells – come from within abnormal body cells – “starve” healthy cells

How are invaders recognized? Antigens chemical name tags on the surface of every cell – Protein “self” vs. “invader” – ALL BASED ON SHAPE one of your own cells disease-causing virus disease-causing bacteria antigens say: “I belong here” antigens say: “I am an invader” antigens say: “I am an invader”

1st line: Physical Barriers non-specific defense external barriers skin & mucus membranes excretions sweat stomach acid tears mucus saliva “lick your wounds” Lining of trachea: ciliated cells & mucus secreting cells

2nd: Generalist, broad range patrols White blood cells attack invaders that get through the skin recognize invader by reading antigen surface name tag – BASED ON SHAPE phagocyte cells macrophages “big eaters” that engulf via endocytosis, then fuse with lysosome, and finally exocytosis) Macrophage “eating” bacteria

Why do injuries swell? Inflammation - injured cells release chemical signals histamines increases blood flow (red and warm) brings more white blood cells to fight bacteria (pus) brings more red blood cells & clotting factors to repair

Fever When a local response is not enough full body response to infection raises body temperature – 37 C or 98.6 F TOO high = dangerous higher temperature helps in defense slows growth and metabolism of pathogens helps macrophages speeds up repair of tissues Certain bacterial infections can induce an overwhelming systemic inflammatory response leading to a condition known as septic shock. Characterized by high fever and low blood pressure, septic shock is the most common cause of death in U.S. critical care units. Clearly, while local inflammation is an essential step toward healing, widespread inflammation can be devastating.

3rd line: Lymphocytes Specific defense responds to specific invaders B cell Specific defense responds to specific invaders recognizes specific foreign antigens white blood cells B cells & antibodies T cells

B cells & antibodies ACTIVE IMMUNITY white blood cells that attack invaders in blood mature in Bone marrow Patrolling B cells make antibodies against invader immediately Memory B cells remembers invader can make antibodies quickly the next time protects you from getting disease more than once

Antibodies Proteins made by B cells that tag invaders in the blood so macrophages can eat them tag says “this is an invader”  gotcha! biological “handcuffs” antibody attaches to antigen of invader – they “FIT” Y invading germs tagged with antibodies B cells releasing antibodies Y Y macrophage eating tagged invaders

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

B Cells T Cells

Vaccinations Jonas Salk Exposure to harmless version (“dead”, weakened, or part) of a pathogen (“germ”) stimulates immune system to produce antibodies to invader - ACTIVE IMMUNITY rapid response if future exposure Most successful against viral diseases Ex: flu, chicken pox, HPV, MMR, swine flu, whooping cough, polio, small pox Jonas Salk Developed first vaccine against polio

Curing you of disease Antibiotics = medicine advantage disadvantage kill bacteria that have successfully invaded you make you well after being sick disadvantage use only after sick only good against bacteria possible development of resistance by bacteria (if don’t use correctly) – ALWAYS TAKE THE ENTIRE Rx can get sick again

Diseases of the immune system HIV: Human Immunodeficiency Virus infects helper T cells helper T cells can’t activate rest of immune system body doesn’t hear the alarm AIDS: Acquired ImmunoDeficiency Syndrome immune system is weakened infections by other diseases death from other invading diseases or cancer

Immune system malfunctions Auto-immune diseases immune system attacks own cells lupus antibodies attack many different body cells rheumatoid arthritis antibodies causing damage to cartilage & bone diabetes insulin-making cells of pancreas attacked & destroyed multiple sclerosis T cells attack myelin sheath of brain & spinal cord nerves fatal

Immune system malfunctions Allergies produce histamines over-reaction to harmless antigens allergens proteins on pollen proteins from dust mites proteins in animal saliva body mistakenly thinks they are harmful attackers (antigens)

http://www.youtube.com/watch?v=lrYlZJiuf18 Watch the video again… Can you see the flow or steps to an Immune Response?