“Fighting the Enemy Within”

1. phagocytic leukocyte “Fighting the Enemy Within” Immune System lymphocytes attacking cancer cell lymph system

2. Avenues of attack • Points of entry • 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

3. 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 • 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

4. How are invaders recognized? • Antigens • chemical name tags on the surface of every cell – Protein • “self” vs. “invader” – ALL BASED ON SHAPE disease-causingbacteria one of yourown cells disease-causingvirus antigens say:“I am an invader” antigens say:“I belong here” antigens say:“I am an invader”

5. 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

6. 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” • “eat” like amebas • engulf (endocytosis, then fuse with lysosome, and finally exocytosis) Macrophage “eating” bacteria

7. Why do injuries swell? 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 • Inflammation - injured cells release chemical signals

8. 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 – remember enzymes???? • higher temperature helps in defense • slows growth and metabolism of pathogens • helps macrophages • speeds up repair of tissues

9. 3rd line: Lymphocytes B cell • Specific defense • responds to specific invaders • recognizes specific foreign antigens • white blood cells • B cells & antibodies • T cells

10. B cells & antibodies ACTIVE IMMUNITY • B cells • 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

11. Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y 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” invading germs tagged with antibodies B cells releasing antibodies Y macrophageeating tagged invaders

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

13. Vaccinations • 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

14. Protecting you from disease • Vaccinations – Active Immunity • advantage • don’t get illness • long term immunity - produce antibodies for life • works against many viruses & bacteria • disadvantage • not possible against all invaders • Breastfeeding - Passive Immunity • mother’s milk gives baby antibodies & keeps baby healthy

15. Curing you of disease • Antibiotics = medicine • advantage • 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

16. 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

17. 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

18. 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 harmfulattackers (antigens)