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Today is Thursday, February 19 th, 2015 Pre-Class: How many tiers does the immune system have? (take a guess) Also, whats the best way to make your immune system more effective? In This Lesson: Immunology (Lesson 3 of 3)

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Todays Agenda The Immune System Including all three levels of response. Antibodies Immunity Where is this in my book? Chapter 43.

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By the end of this lesson You should be able to narrate the immune response to a pathogen with details for each of the three levels. You should be able to distinguish between five general types of white blood cells with detail given to the four main types of lymphocytes. You should be able to describe the five classes of immunoglobulins.

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Perspective This is the part where I try to give you guys inspiration or motivation to learn. Ill be honest with you and this is not a joke to me this is one of the most beautiful things in biology. Think about it weve learned about evolution and all the amazing ways organisms have developed to become more efficient at life. Now we look at a part of the body that has had, by far, the most intense selective pressures for the longest evolutionary time.

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Perspective Now youre going to witness conflict on a molecular scale. Quite literally, this is a battle for resources between an invader and the body. Watch as cells interact with one another with one side trying to outdo the other and exploit weaknesses. The best part? Nothing is actually conscious. Its nothing short of brilliant. Its nothing short of amazing.

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The Germ Theory Today, were well aware of germs. We know that things we cant see can hurt us. However, there was a time when the idea of a microscopic pathogen was laughable. Its the 1860s. Enter Louis Pasteur.

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The Germ Theory Louis Pasteur (same dude as the pasteurization process) takes on a centuries-old debate about the nature of disease. He shows that disease is caused by bacteria through: Breakdown of tissue. Toxin release. Further, disease can be transmitted by: Air Water Food Contact Invertebrates (especially insects) Louis Pasteur

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The Germ Theory So the Germ Theory is born. The Germ Theory simply states that microscopic organisms are capable of causing disease. So, no more is it the vapors making women ill. http://www.broadsheet.ie/wp-content/uploads/2011/06/mlady.gif

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Fast forward to 1890 Robert Koch, considered the father of modern bacteriology, puts forth Kochs Postulates to connect a pathogen to a disease. A researcher must: Find the same pathogen in all diseased organisms. Isolate and grow the pathogen in a lab. Sicken healthy animals with the pathogen. Isolate the same pathogen from the newly- infected organism and grow it again. http://upload.wikimedia.org/wikipedia/commons/thumb/8/8d/RobertKoch_cropped.jpg/190px-RobertKoch_cropped.jpg Robert Koch

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Kochs Postulates

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Disease Transmission With the Germ Theory comes five modes of disease transmission: Direct contact Example: Infectious mononucleosis, chlamydia. Indirect contact A surface that transfers disease like a doorknob a sick person touches that infects someone else is a fomite. Example: The common cold. Aerosol [large water/mist droplet] Example: Respiratory viruses. Airborne [small droplet] Example: Measles, tuberculosis, chicken pox, smallpox. Vector [other organism or food] A vector is another organism that transfers a disease. Example: E. coli, listeria, bubonic plague. http://phprimer.afmc.ca/Part3-PracticeImprovingHealth/Chapter11InfectiousDiseaseControl/Modesandcontroloftransmission

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Case-in-Point: Typhoid Mary This is Mary Mallon (1869-1938), better known as Typhoid Mary. Let me tell you why she doesnt look happy. She carried typhoid fever but was completely asymptomatic. She also happened to work as a private cook for families. Whoops. Because of her job, she continuously made people ill. Over the course of her career she infected 51 and is linked to at least 3 deaths, but possibly up to 50. She is also quoted to have said she did not understand the purpose of hand washing and refused to give up her job as a cook. She was forcibly quarantined by the City of New York twice and died after almost 30 years in isolation. It appears that Salmonella typhi may hide in white blood cells called macrophages. http://upload.wikimedia.org/wikipedia/commons/e/eb/Mary_Mallon_%28Typhoid_Mary%29.jpg Mary Mallon

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Immune System So along with the advancement of bacteriology, science also began to turn its attention to immunology (how your body defends itself). Whats your bodys first line of defense? The first line of the immune system? The boundaries of your body.

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Infection Thus, the points of entry for a pathogen include: Digestive system Respiratory system Urogenital tract Breaks in skin (including cuts, eyes, ears) Infection can then spread via: The circulatory system The lymphatic system

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Lines of Defense Summary Slide 1 st Line: Barriers Skin, mucus membranes, secretions. 2 nd Line: Non-Specific Broad, internal defense. Known as the innate response. 3 rd Line: Specific Acquired immunity specific to the pathogen. Known as the adaptive/acquired response.

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First Line of Defense: External Examples The trachea/windpipe is lined with cells that have cilia (to sweep out pathogens) and mucus (to stop them). Tears and saliva wash pathogens away and have lysozymes (enzymes that damage bacterial cell walls). Sweat (pH 3-5) and stomach acid (pH 2) denature proteins.

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Infection Once a pathogen enters your body, its up to your immune system to fight it off. After all, youre a nice environment for a pathogen. Youre warm. Youre packed with nutrients. You dont even have cell walls! Pathogens can then circulate viathe circulatory system. Luckily, you have an alternate circulatory system for the immune system called the lymphatic system.

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The Lymphatic System

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Production of Red/White Blood Cells Inflammatory Response Fight ParasitesShort-lived Phagocytes (most white blood cells) Become Macrophages

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Second Line of Defense: Internal White blood cells, broadly known as leukocytes, are actually several different cells. Furthermore, they have equivalents that exist within tissues that dont circulate but play similar roles. Theres also other stuff that floats around, plus the blood liquid itself. Heres a guide Mast Cell Macrophage Neutrophil Natural Killer Cell

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Blood Plasma and Blood Serum Blood plasma is the liquid in blood, not including the blood cells. It includes clotting factors like fibrinogens. Blood serum does not include fibrinogens.

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Blood Components Fibrinogens Proteins that help in clotting. Platelets Cells that help in clotting. Erythrocytes Red blood cells [RBC] carry oxygen. 4.8-5.2 million RBC per milliliter of human blood. Leukocytes White blood cells [WBC] immune system. 4000-10,000 WBC per milliliter of human blood. Five major classes. http://bme.virginia.edu/ley/leukocytes.html

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The Five Types of Leukocytes 1.Neutrophils (40%-75% of WBC) Live for about three days. Find their way to infection site by chemoattractants. Ingest and destroy bacteria. 2.Eosinophils (1%-6% of WBC) Live for weeks. Move to infection site via chemoattractants and kill bacteria. Defend against multicellular invaders (like worms). http://bme.virginia.edu/ley/leukocytes.html

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The Five Types of Leukocytes 3.Basophils (