BIOL 118 1st Edition Lecture 32 Outline of Last Lecture I Introduction to Animal Reproduction II Asexual Sexual Reproduction III Mechanisms of Sexual Reproduction Gametogenesis IV Fertilization Egg Development V Role of Sex Hormones in Sexual Reproduction VI Pregnancy Birth In Mammals Outline of Current Lecture I Introduction to the Immune System of Animals II Innate Immunity Adaptive Immunity Current Lecture Introduction to the Immune System of Animals All organisms are targets for diseases from pathogens disease causing organisms o Bacteria parasites viruses fungi protists Immune system of the animal fights off the pathogens keeps the animal healthy Immunity resistance to protection against disease causing pathogens o Prevents individuals from contracting a disease more than once Immunization conferring of immunity to a particular disease o Vaccination introduction of a weakened or altered pathogen to prime the body s immune system so it fights later infections effectively Innate Immunity Adaptive Immunity Innate immunity immune system cells that are ready to respond to foreign invaders at all times o Is nonspecific responds in the same way to all antigens Antigen any foreign molecule that can initiate an immune response Cells that require activation confer adaptive immunity o These cells respond in an extremely specific way to the particular strains of bacteria viruses or fungi that enter the body Innate immune response body s nonspecific response to pathogens involves leukocytes such as mast cells macrophages These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Alerted to the presence of foreign invaders by antigens that are found on the surfaces of pathogens but not on host cells o Steps When skin breaks pathogens enter a wound Platelets release blood clotting proteins at the wound site Wounded tissues macrophages at the wound site secrete chemokines signaling molecules that recruit immune cells by forming a gradient to mark the path to the site Mast cells release chemical messengers that constrict blood vessels near the wound reducing blood flow thus blood loss Also secrete histamine other signaling molecules which dilate blood vessels slightly farther away from the wound making them more permeable Neutrophils macrophages remove pathogens by phagocytosis engulfing digesting of foreign particles Macrophages secrete cytokines chemicals that attract other immune system cells to the site activate cells involved in tissue repair Also induce fever elevated body temperature that aids in healing Adaptive immune response based on interactions between specific immune system cells a specific antigen o Antibodies proteins produced secreted by certain lymphocytes bind to only a specific part of a specific antigen o Four key characteristics Specificity antibodies other components of the adaptive immune system bind only to specific sites on specific antigens Diversity adaptive response recognizes an almost limitless array of antigens Memory can be reactivated quickly if it recognizes antigens from a previous infection Self nonself recognition molecules that are produced by an individual do not act as antigens so the adaptive immune system can distinguish between self nonself o Lymphocytes cells involved in adaptive immune response Produced in bone marrow tissue that fills that cavities in bones Can also originate in spleen lymphatic organ located in abdominal cavity B cells mature in bone marrow T cells mature in the thymus Lymphocytes recognize antigens become activated in the spleen lymph nodes small oval organs located throughout the body Circulate through the blood the secondary organs of the immune system lymph nodes spleen lymphatic ducts Lymphatic ducts thin walled branching tubules that transport lymph throughout the body in the lymphatic system Self from Nonself or Autoimmunity If a B cell receptor or T cell receptor responded to a self molecule molecule belonging to the host the receptor would trigger an immune response o Autoimmunity anti self reaction which can lead to self destruction To avoid anti self T B cells are destroyed before they mature Examples of autoimmunity o Multiple sclerosis results from the production of anti self T cells that attack the myelin sheath of nerve fibers resulting in muscular coordination problems o Rheumatoid arthritis develops when T cells antibodies alter the lining of joints o Type 1 diabetes mellitus occurs when T cells attack kill insulin secreting cells in the pancreas resulting in an inability to regulate blood sugar levels
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