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The immune system

The immune system. Andrea Duncan. Non-specific defenses. (innate). Physical barriers. Skin and mucous membranes Bark. Biochemical barriers. Stomach Saliva, sweat, tears Fever inflammation Phagocytes: Consume foreign or aged materials in bloodstream and lymphatic system

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The immune system

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  1. The immune system Andrea Duncan

  2. Non-specific defenses (innate)

  3. Physical barriers • Skin and mucous membranes • Bark

  4. Biochemical barriers • Stomach • Saliva, sweat, tears • Fever • inflammation • Phagocytes: Consume foreign or aged materials in bloodstream and lymphatic system • Leukocyte (white blood cell)—natural killer cell, kills virus-infected cells

  5. Specific defenses (adaptive)

  6. Components of blood • erythrocytes (red blood cells) • leukocytes (white blood cells) • platelets

  7. Leukocytes • Granulocytes • Eosinophils—focus on parasites of the skin and lungs • Neutrophils—Most common leukocyte, short-lived, respond to inflammation in an injury (chemotaxis), macrophagial and cytotoxic to foreign bodies • Basophils—cause inflammation and produce histamine • Monocytes—turn into specified macrophages, ingest dead neutrophils

  8. Leukocytes continued • Lymphocytes • Develop in primary lymphoid organs and live in secondary lymphoid organs (lymph nodes, spleen, appendix, tonsils, intestinal tract, under skin) • Bone marrow—produces stem cells, which differentiate into different types of blood cells • Travel through both blood and lymphatic systems, pass from blood through lymph nodes, pass from lymphatic system through thoracic duct • Two types

  9. B cells • Produced and Develop in bone marrow • Antibody-mediated immune response • Produce antibodies (protein) when they encounter an antigen

  10. B cell Antibodies • Each B-cell is covered with the same antibody, therefore can only bind to that specific antigen • Structure: 4 polypeptide chains, two identical sides, 2 binding sites; many different amino acid sequences on binding sites for different purposes, different combinations of antibody chains account for more types of antibodies than there are genes (antibody diversity) • Antibodies mark antigen for non-specific destruction by binding to them • May bind multiple antigens together for easy destruction, or mark them for other cells to destroy—complement system

  11. Once bound to an antigen, cell multiplies into 2 types of cell: • Plasma cells • Produce more of the same antibody to fight specific antigen, short lifespan • Memory B cells • Exist to respond if antigen returns to body, less of these made

  12. T cells • Produced in bone marrow, Develop in thymus (just above heart) • Cell-mediated immune response • Produce chemicals that produce and maintain an immune response • T-cell receptors on surface • activate when parts of an antigen are recognized on an MHC protein—both occur on the surface of a cell that is infected by a virus • Differentiate between foreign and self by recognizing HLA molecules on a cell…all cells of the body except for red blood cells have a different combination of these molecules on their surface—tolerance • Organ transplant—more successful if HLAs of donor and recipient are mostly identical (lesser immune response)

  13. Types of T cell: • CTLs—Cytotoxic T lymphocytes • Limit viral infections by killing virus-infected cells • TH—Helper T cells • Produce cytokines, which stimulate other lymphocytes to reproduce • Speeds up production of B plasma cells, which in turn boosts release of specific antibodies into the bloodstream • Th1—stimulate cytotoxic response • Th2—stimulate antibody response

  14. video

  15. Immune memory • Long-term resistance to repeat offenders—clonal selection • Primary immune response—when first exposed to antigen • Secondary immune response—reaction using memory B cells • Antiviral drugs—prevent virus from reproducing • Antibiotics—attack bacteria

  16. Vaccines • dead or weakened organisms that make body create immunity without organism actually getting infected • Inactivated=unable to reproduce • Attenuated=unable to cause disease • Chicken pox, smallpox, measles, mumps, Hepatitis A and B, rabies, rubella, typhoid, tuberculosis • Edward Jenner—cured smallpox • Louis Pasteur—vaccine for rabies and others • Currently research occurring for a vaccine for AIDS

  17. Immune system malfunctions • Immune suppression • Medication and illegal drugs • Infectious agents—HIV • Immune hyperactivity • Allergic reactions—poison ivy, metallic, asthma, seasonal allergies • Autoimmunity • Body attacks its own cells—rheumatoid arthritis, MS, diabetes • Caused by combination of genetic susceptibility and environmental factors • Leukemia • Lymphocytes turn cancerous, malfunctioning lymphocytes crowd out normal ones and decrease immune system • May break off into bloodstream or bone marrow

  18. HIV/AIDS • HIV=human immunodeficiency virus • AIDS=acquired immunodeficiency syndrome

  19. HIV/AIDS • Affects helper T cells, sometimes macrophages and nerve cells • Attachment site: CD4 protein, attaching protein: gp 120 • Viral infection…(steps review?) • Result: decrease in helper T cells, greatly weakens immune system; constant war between helper T cells and HIV

  20. Why no cure? • Retrovirus—RNA material, mutation • Most of life cycle inside cells • video

  21. Works Cited "Discovery Health "How Your Immune System Works"" Discovery Health "Health Guides" Web. 13 June 2011. <http://health.howstuffworks.com/human- body/systems/immune/immune-system11.htm>. Greenberg, Jon. BSCS Biology: a Molecular Approach. New York: Glencoe McGraw-Hill, 2001. Print. "HIV, AIDS and the Immune System." Information Technology. Web. 13 June 2011. <http://people.ku.edu/~jbrown/hiv.html>. Leukocyte functions. Digital image. Immune Cell Survival: Walking a Tightrope. Web. 13 June 2011. <http://lpi.oregonstate.edu/sp-su98/images/immune1.gif>. "Untitled Document." University of Virginia | Department of Biomedical Engineering (BME). Web. 13 June 2011. <http://bme.virginia.edu/ley/leukocytes.html>. YouTube - 3D Medical Animation: Antibody Immune Response‬‏. YouTube - Broadcast Yourself. Web. 13 June 2011. <http://www.youtube.com/watch?v=lrYlZJiuf18>. YouTube - HIV Destroys Helper T-cells | Biology | Anatomy | Immunology‬‏. YouTube - Broadcast Yourself. Web. 13 June 2011. <http://www.youtube.com/watch?v=U2h0ECyMWhE>. YouTube - Introduction to How the Immune System Works | Biology | Anatomy | Immunology‬‏. YouTube - Broadcast Yourself. Web. 13 June 2011. <http://www.youtube.com/watch?v=IWMJIMzsEMg>. YouTube - Macrophages, B-cells, Pathogens, Antibody Immune Response‬‏. YouTube - Broadcast Yourself. Web. 13 June 2011. <http://www.youtube.com/watch?v=iDYL4x1Q6uU>.

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