Chapter 43 Quizzes: Self Activities Chapter Cum. Animations     Words   Appendix    Summary   Art    Art 

Unit 7: Animal Form and Function The Immune System Review
  1. Animals have two major kinds of defense against pathogens such as , , or other foreign substances.
    • immunity is acquired at birth before any exposure to pathogens and involves rapid, responses.
       
       
    • (adaptive) immunity develops only after exposure to the inducing agent and involves slower, responses involving and .
     
     
  2. Innate immunity:
    • External defenses
      • The skin provides a physical barrier; secretions from (oil) and glands provide an environment with a pH between 3 and 5 to prevent colonization of many microbes. Proteins such as digest the cell walls of many bacteria.
         
         
      • Cells of the mucous membranes produce , a viscous fluid that traps microbes and other particles. In the trachea, ciliated cells sweep mucus and entrapped matter upward, away from lungs.
       
       
    • Internal defenses
      • Phagocytes are types of blood cells which ingest invading microorganisms by .
         
         
      • The system contains a type of phagocyte called , as well as cells and , which carry out various defensive actions at nodes.
         
         
      • Natural (NK) cells attack virus-infected body cells and cancer cells by , or programmed cell death.
     
     
  3. Acquired immunity:
    • Lymphocytes circulate through the and have antigen receptors called membrane or membrane made of chains whose regions bind to the epitopes of . There are two main types of lymphocytes.
      • cell receptors have two of chains that bind to specific, intact .
         
         
      • cell receptors have one and one chain, and bind to small fragments of antigens, which in turn bind to (Major Histocompatibility Complex) proteins involved in nonself recognition.
       
       
    • (antibody-mediated) immunity:
      • In a immune response, binding of antigen to a mature induces selection, resulting in the proliferation of cells into long-lived cells and short–lived cells that secrete .
         
         
      • The clonal selection of cells generates plasma cells that secrete , or , resulting in elimination of foreign particles by and complement-mediated .
         
         
      • In the immune response, cells facilitate a faster, more efficient response.
       
       
    • mediated immunity is similar to humoral immunity, but involves the clonal selection of T cells.
      • T cells are activated upon exposure to antigens and secrete that stimulate other lymphocytes.
         
         
      • Cytotoxic T cells attack infected and cells, and also tissues by secreting and other enzymes that destroy the target cell.
     
     
    Review: Immune Responses
     
     
  4. The ABO blood group is a result of antibodies to nonself on blood cells.
     
     
  5. Allergies are exaggerated (hypersensitive) responses to antigens called .
     
     
  6. Acquired Immunodeficiency Syndrome (AIDS) is caused by the Human Immunodeficiency (HIV ) whose genome is single-stranded , and results in a loss of T cells. impairing both and -mediated immune responses.
bio1152 Home May 25, 2007 Print Print