Unit 31 Immune System


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Unit 31 Immune System

  1. 1. KEY CONCEPT Germs cause many diseases in humans.
  2. 2. <ul><li>Germ theory states that microscopic particles cause certain diseases. </li></ul><ul><li>Germ theory proposes that microorganisms cause diseases. </li></ul><ul><ul><li>proposed by Louis Pasteur </li></ul></ul><ul><ul><li>led to rapid advances in understanding disease </li></ul></ul>
  3. 3. <ul><li>Disease-causing agents are called pathogens. </li></ul><ul><li>Koch’s postulates support the theory. </li></ul>
  4. 4. <ul><li>There are different types of pathogens. </li></ul><ul><li>Bacteria are single-celled organisms. </li></ul><ul><ul><li>cause illness by destroying cells </li></ul></ul><ul><ul><li>release toxic chemicals </li></ul></ul>
  5. 5. <ul><li>Viruses are genetic material surrounded by a protein coat. </li></ul><ul><ul><li>force host cells to make more viruses </li></ul></ul><ul><ul><li>very small </li></ul></ul>
  6. 6. <ul><li>Fungi can be multicellular or single-celled. </li></ul><ul><ul><li>take nutrients from host cells </li></ul></ul><ul><ul><li>occur in warm and damp places </li></ul></ul>
  7. 7. <ul><li>Protozoa are single-celled organisms. </li></ul><ul><ul><li>use host cells to complete their life cycles </li></ul></ul><ul><ul><li>take nutrients from host cell </li></ul></ul>
  8. 8. <ul><li>Parasites are multicellular organisms. </li></ul><ul><ul><li>grow and feed on a host </li></ul></ul><ul><ul><li>possibly kill the host </li></ul></ul>
  9. 9. <ul><li>Different pathogen cause common infectious diseases. </li></ul>
  10. 10. <ul><li>Pathogens can enter the body in different ways. </li></ul><ul><li>Pathogens can be transferred by direct or indirect contact. </li></ul><ul><li>Indirect contact does not require touching an infected individual. </li></ul><ul><ul><li>touching an infected surface </li></ul></ul><ul><ul><li>breathing in infected air </li></ul></ul>
  11. 11. <ul><li>Direct contact requires touching an infected individual. Includes: </li></ul><ul><ul><li>kissing </li></ul></ul><ul><ul><li>sexual intercourse </li></ul></ul><ul><ul><li>hand shaking </li></ul></ul><ul><li>Vectors carry a pathogen and transmit it into healthy cells. </li></ul>tick
  12. 12. KEY CONCEPT The immune systems consists of organs, cells, and molecules that fight infections.
  13. 13. <ul><li>Many body systems protect you from pathogens. </li></ul><ul><li>The immune system is the body system that fights off infection and pathogens. </li></ul><ul><li>Many other tissues and systems help the immune system. </li></ul><ul><ul><li>Skin is a physical barrier to infection. </li></ul></ul><ul><ul><li>Mucous membranes trap pathogens entering the body. </li></ul></ul><ul><ul><li>The circulatory system transports immune cells. </li></ul></ul>
  14. 14. <ul><li>Cells and proteins fight the body’s infections. </li></ul><ul><li>White blood cells attack infections inside the body. </li></ul><ul><ul><li>Phagocytes engulf and destroy pathogens. </li></ul></ul><ul><ul><li>T cells destroy infected cells. </li></ul></ul><ul><ul><li>B cells produce antibodies. </li></ul></ul>
  15. 15. <ul><li>Three types of proteins fight off invading pathogens. </li></ul><ul><ul><li>Complement proteins weaken pathogen membranes. </li></ul></ul><ul><ul><li>Antibodies make pathogens ineffective. </li></ul></ul><ul><ul><li>Interferons prevent viruses from infecting healthy cells. </li></ul></ul>antibody pathogens
  16. 16. <ul><li>Immunity prevents a person from getting sick from a pathogen. </li></ul><ul><li>In all immunity, pathogens are destroyed before you get sick. </li></ul><ul><li>Passive immunity occurs without an immune response. </li></ul><ul><ul><li>mother’s milk </li></ul></ul><ul><ul><li>genetics </li></ul></ul><ul><li>Active immunity occurs after a specific immune response </li></ul>
  17. 17. KEY CONCEPT The immune system has many responses to pathogens and foreign cells.
  18. 18. <ul><li>Many body systems work to produce nonspecific responses. </li></ul><ul><li>Nonspecific responses are the same for every pathogen. </li></ul><ul><li>In inflammation, blood vessels become leaky. </li></ul><ul><ul><li>white blood cells move toward infection and damaged tissue </li></ul></ul><ul><ul><li>characterized by swelling, redness, and pain </li></ul></ul>capillary wall extracellular space white blood cell
  19. 19. <ul><li>In fever, body temperature increases. </li></ul><ul><ul><li>High fevers can cause seizure, brain damage, and even death. </li></ul></ul><ul><ul><li>Low fevers stimulate white blood cells to mature. </li></ul></ul>
  20. 20. <ul><li>Cells of the immune system produce specific responses. </li></ul><ul><li>Specific immune responses begin with the detection of antigens. </li></ul><ul><ul><li>Antigens are surface proteins on pathogens. </li></ul></ul><ul><ul><li>Each pathogen has a different antigen. </li></ul></ul>virus antigens
  21. 21. <ul><li>There are two specific immune responses. </li></ul><ul><ul><li>Cellular immunity uses T cells to destroy infected body cells. </li></ul></ul>pathogen antigens T cell receptors activated T cells antigens memory T cells
  22. 22. <ul><li>There are two specific immune responses. </li></ul><ul><ul><li>Humoral immunity uses B cells to produce antibodies. </li></ul></ul>memory B cells activated B cells antibodies B cell T cell pathogen
  23. 23. <ul><li>Both responses produce memory cells. </li></ul><ul><ul><li>specialized T and B cells </li></ul></ul><ul><ul><li>provide acquired (active) immunity </li></ul></ul>B cell T cell
  24. 24. <ul><li>The immune system rejects foreign tissues. </li></ul><ul><li>Tissue rejection occurs in organ or tissue transplants. </li></ul><ul><li>Tissue rejection is the result of an immune response. </li></ul><ul><ul><li>immune system detects protein markers on the donor tissue </li></ul></ul><ul><ul><li>makes antibodies against the donor’s tissue </li></ul></ul>
  25. 25. KEY CONCEPT Living in a clean environment and building immunity help keep a person healthy.
  26. 26. <ul><li>Many methods are used to control pathogens. </li></ul><ul><li>Antibiotics and antiseptics cause pathogens to burst. </li></ul>
  27. 27. <ul><li>Antiseptics kill pathogens outside of the body. </li></ul><ul><ul><li>do not target specific pathogens </li></ul></ul><ul><ul><li>examples include vinegar and soap </li></ul></ul><ul><li>Antibiotics kill pathogens inside the body. </li></ul><ul><ul><li>target one specific bacterium or fungus </li></ul></ul><ul><ul><li>not effective against viruses </li></ul></ul>
  28. 28. <ul><li>Antibiotic resistance can cause medicines to become ineffective. </li></ul><ul><ul><li>Some bacteria in a population have genes that make them immune to antibiotics. </li></ul></ul><ul><ul><li>These bacteria spread the gene, making the antibiotics useless. </li></ul></ul>A bacterium carries genes for antibiotic resistance on a plasmid. A copy of the plasmid is transferred through conjugation. Resistance is quickly spread through many bacteria.
  29. 29. <ul><li>Vaccines artificially produce acquired immunity. </li></ul><ul><li>Vaccines also control pathogens and disease. </li></ul><ul><ul><li>given to prevent illness </li></ul></ul><ul><ul><li>contain the antigen of a weakened pathogen </li></ul></ul>
  30. 30. <ul><li>Vaccination provides immunity. </li></ul><ul><ul><li>stimulates a specific immune response </li></ul></ul><ul><ul><li>allows immune system to respond quickly to infection </li></ul></ul><ul><ul><li>causes memory cells to be produced </li></ul></ul><ul><ul><li>has such a fast response, a person will not get sick </li></ul></ul>A memory B cell is stimulated when the real pathogen binds to it. 2 The B cell quickly activates and makes antibodies that fight the pathogens before you get sick. 3 Antigens in a vaccine trigger an immune response, and memory B cells are made. 1 memory B cells
  31. 31. KEY CONCEPT An overactive immune system can make the body very unhealthy.
  32. 32. <ul><li>Allergies occur when the immune system responds to harmless antigens. </li></ul><ul><li>An allergy is an response to a harmless antigen. </li></ul><ul><li>Allergies are caused by allergens. </li></ul><ul><ul><li>Allergens are antigens that cause an allergic reaction. </li></ul></ul><ul><ul><li>Allergens cause inflammation responses. </li></ul></ul>
  33. 33. <ul><li>There are many different allergens. </li></ul><ul><ul><li>food, e.g. peanuts, milk, wheat, etc. </li></ul></ul><ul><ul><li>airborne, e.g. pollen, dust mite feces, mold, etc. </li></ul></ul><ul><ul><li>chemical, e.g. nickel, medicine, bee stings, etc. </li></ul></ul>
  34. 34. <ul><li>Allergens can cause anaphylaxis. </li></ul><ul><ul><li>Anaphylaxis is an extreme inflammation response. </li></ul></ul><ul><ul><li>Blood vessels and airways become too porous. </li></ul></ul><ul><ul><li>If not treated immediately, anaphylaxis can cause death. </li></ul></ul>
  35. 35. <ul><li>In autoimmune diseases, white blood cells attack the body’s healthy cells. </li></ul><ul><li>Autoimmune diseases are failures of the immune system. </li></ul><ul><ul><li>White blood cells cannot recognize healthy cells. </li></ul></ul><ul><ul><li>White blood cells attack healthy body cells. </li></ul></ul><ul><ul><li>Tissues fail because of attack. </li></ul></ul>
  36. 36. <ul><li>There are over 60 autoimmune diseases. </li></ul>
  37. 37. KEY CONCEPT When the immune system is weakened, the body cannot fight off disease.
  38. 38. <ul><li>Leukemia is characterized by abnormal white blood cells. </li></ul><ul><ul><li>characterized by immature white blood cells </li></ul></ul><ul><ul><li>causes weakened immune system </li></ul></ul><ul><li>Leukemia is cancer of the bone marrow. </li></ul>
  39. 39. <ul><li>Leukemia leads to opportunistic infections. </li></ul><ul><ul><li>occur because white blood cells cannot fight infections </li></ul></ul><ul><ul><li>if immune system were healthy, would fight these infections </li></ul></ul>
  40. 40. <ul><li>HIV targets the immune system. </li></ul><ul><li>The human immunodeficiency virus (HIV) is a retrovirus. </li></ul><ul><ul><li>attacks and weakens the immune system </li></ul></ul><ul><ul><li>is transmitted by mixing infected blood with a bodily fluid </li></ul></ul>
  41. 41. <ul><li>HIV infection leads to AIDS. </li></ul><ul><ul><li>HIV reproduces in and destroys T cells. </li></ul></ul><ul><ul><li>The body cannot replace T cells fast enough. </li></ul></ul><ul><ul><li>T cells cannot help in immune responses. </li></ul></ul>HIV T cell dead T cell antibody activated B cell
  42. 42. <ul><li>AIDS is acquired immune deficiency syndrome. </li></ul><ul><ul><li>several opportunistic infections </li></ul></ul><ul><ul><li>very low amount of T cells </li></ul></ul>
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