Pathophysiology Exam 1 Questions & Answers Latest Updated

What is the purpose of the immune system? - Answer protect us from microbial agents and cancer cells What is an antigen? - Answer a substance which reacts with products of the immune response (antibodies and T cell receptors) What is an antibody? - Answer glycoprotein which specifically binds to an antigen and carries out immune functions such as activating the complement pathway Name three characteristics of innate immunity - Answer 1. Acts within minutes; immune defense we are born with 2. No specific recognition of invader 3. Response is not improved with 2nd exposure to the same invader (no memory cells) Name three characteristics of adaptive/acquired immunity - Answer 1. Takes days to become effective 2. Highly specific response to millions of antigens from different invaders 3. Memory cells are made: allow for faster and more effective immune response upon 2nd response to same invader cellular immunity - Answer Part of adaptive immunity. mediated by T lymphocytes. Most active in response to intracellular infections and cancer cells humoral immunity - Answer part of adaptive immunity. mediated by b lymphocytes. antibody mediated immune defense; most active in response to extracellular infections (bacteria) Name 5 components of innate immunity - Answer 1. natural barriers 2. neutrophils and macrophages 3. complement activation 4. Natural killer cells 5. interferons Examples of natural barriers of infection - Answer skin; cilia and mucus in respiratory tract; mucus in GI tract; gastric juice with acid to kill microbes What is the function of neutrophils and macrophages? - Answer these are phagocytic cells which can engulf and kill microbial organisms intracellularly Describe complement activation - Answer Upon contact with microbial surfaces, complement proteins: 1. form membrane attack complex (MAC) and drill holes in invaders 2. help phagocytic cells recognize and engulf invaders 3. attract neutrophils to invader site to kill invader Natural Killer (NK) cells - Answer directly ill virus-infected cells and cancer cells by perforating membrane of invader Interferons - Answer a cytokine released by virally infected cells. Stimulate production of proteins which prevent replication and formation of virus within surrounding uninfected cells. What are the cells of adaptive/acquired immunity? (4) - Answer 1. Macrophages 2. B lymphocytes 3. Cytotoxic T cells 4. Helper T cells What is the function of macrophages in adaptive immunity? - Answer present antigen to T lymphocytes What is the function of B lymphocytes in adaptive immunity? - Answer transform into plasma cells and make antibodies What is the function of cytotoxic t cells in adaptive immunity? - Answer directly kill infected cells and cancer cells Where do B cells originate and mature? - Answer originate and mature in the bone marrow (primary lymphoid organ) Where to T cells originate and mature? - Answer originate in the bone marrow and mature in the thymus (primary lymphoid organ) What are secondary lymphoid tissues? - Answer tissue in which lympocytes come into contact with antigens of invaders. killing of invaders occurs in these tissues. Products of immune response are developed to fight the same invaders infecting other body tissues What happens in the lymph nodes? - Answer Invaders in the lymph go to the lymph nodes. memory B cells, helper T cells and cytotoxic T cells are made so that future exposure to same invader will be faster and more effective. Macrophages kill invaders in lymph nodes. What happens in the spleen? - Answer invaders from blood filter through spleen. Similar activities as lymph nodes MALT - Answer mucosal associated lymphoid tissue. B and T cells distributed in the epithelial lining of resp, GI, urinary tracts to protect from invaders. What is the purpose of the immune system? - Answer to protect the body from foreign invaders and cancer. Name 2 characteristics of innate immunity - Answer - acts within minutes but never improves because memory cells are not made. - skin, mucus barriers, acidic fluids Cellular vs. Humoral immunity - Answer - Cellular Immunity: dependent on T Lymphocytes- (cell mediated immunity) - Humoral Immunity: dependent on B lymphocytes which make antibodies- (antibody mediated immunity) Components of Innate Immunity and their functions - Answer - neutrophils phagocytose bacteria and macrophages phagocytose viruses and bacteria - When compliment proteins are activated - they help phagocytic cells kill invaders and they form the MAC-kill invading cells. - Interferons- released by infected cells to protect healthy neighboring cells - they stimulate proteins that inhibit reproduction of viral DNA - NK cells: granular lymphocytes that directly kill the invading cells by noticing the absence of a specific protein. Components of acquired immunity and their functions - Answer - T Lymphocytes: made in the bone marrow and develop in the thymus - Helper T Cells: Release cytokines to direct cytotoxic T cells to directly kill invaders and direct B lymphocytes to make antibodies. the generals of acquired immunity. - B Lymphocytes: make antibodies and memory cells - Basophils: release histamine Primary vs. Secondary Lymphoid Organs - Answer - Primary: where lymphocytes are made/matured. - bone marrow: makes B and T cells, B cells mature here. - thymus: where T cells mature. T cells -> helper T or cytotoxic T cells. - Secondary: where invaders are killed by T and B cells: - lymph nodes and Spleen: Macrophages chop up invader--> present peptide to helper T--> order cytotoxic T cells to kill and B cells to make antibodies. - MALT: mucosa full of IgE antibodies that protect from invaders entering the body through openings of the tracts.