Chapter 24- Immune System
Chapter 24- Immune System 70955 - BIOL 104 - 001
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This 4 page Class Notes was uploaded by Aimee Castillon on Friday September 4, 2015. The Class Notes belongs to 70955 - BIOL 104 - 001 at George Mason University taught by TBA in Fall 2015. Since its upload, it has received 35 views. For similar materials see Introductory Biology II in Biology at George Mason University.
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Date Created: 09/04/15
Organization name St u d e n t n a m e student email address BIOL 104 0 Spring 2015 allgifiuigu f ImmMme Learning objectives 1 Compare innate defenses and acquired immunity 2 Describe structure and functions of lymphatic system 3 Analyze how an antigen and antibody interact 4 Compare a primary immune response to a secondary immune response 5 Explain causes of immunodeficiency diseases and allergies What are the two main functions of the lymphatic system Innate Defenses Against Infection 241 Both invertebrates and vertebrates have innate defenses against infection 0 innate defensesfirst line of defense 0 found in animals 0 includes I skin I mucous membranes I phagocytic cells I antimicrobial proteins saliva 0 same response to invaders each time o invertebrates have only innate immunity 0 vertebrates have innate AND acquired immunity see table in PPT and textbook 242 The inflammatory response mobilizes innate defenses 0 tissue damage trigger the inflammatory response 0 inflammatory response can 0 disinfect tissues 0 limit further infection 243 The lymphatic system becomes a crucial battleground during infection 0 lymphatic system is a network of lymphatic vessels and organs 0 lymph organs 0 such as the spleen and lymph nodes 0 are packed with white blood cells that fight infections 0 as lymph circulates through lymphatic organs it o collects I microbes I parts of microbes I microbe toxins o transports them to lymphatic organs I macrophages in lymphatic organs engulf the invaders I lymphocytes may mount an acquired immune response 0 two main functions of lymphatic system 0 return fluid from interstitial spaces to the circulatory system 0 combat infection Antibody specific immunity Inflammatory nonspecific humora specific Acquired Immunity 244 The Acquired immune response counters specific invaders 0 our immune system lymphatic system both Tcells specific macrophages nonspecific humoral immune response whole body noninfected areas cellmediated immune response specific for infectinginfected cells Bcells bone marrows Tcells thymus gland Antibodies attach to the surface of antigens which inactivate them This is called an effector mechanism How are inactivated antigens eliminated from the body Nonspecific defenses such as macrophages and 0 respond to foreign molecules called antigens o acquired immune system 0 reacts to antigens o and remembers an invader 0 infection or vaccination triggers active immunity 0 we can temporarily acquire passive immunity by receiving premade antibodies 245 Lymphocytes mount a dual defense 0 two kinds of lymphocytes carry out the immune response 0 B cells secrete antibodies amp mount humoral immune response 0 T cells attack cells infected w bacteria or viruses I cellmediated immune response 0 millions of kinds of B cells and T cells 0 each w different membrane receptors 0 wait in lymphatic system 0 where they may respond to invaders 246 Antigens have specific regions where antibodies bind to them 0 an gens 0 not usually part of the host 0 most are proteins or large polysaccharides on the surfaces of I vhuses I foreign cells 0 antigenic determinants 0 specific regions on an antigen 0 to which antibodies bind 247 Clonal selection musters defensive forces against specific antigens 0 steps of clonal selection 0 primary immune response clonal selection I produces effector cells I memory cells that may confer lifelong immunity 0 secondary immune response I memory cells are activated by a second exposure to the same antigen I this initiates a faster and stronger response 0 primary vs secondary immune response 0 primary immune response I occurs upon first exposure to an antigen I slower than secondary immune response 0 secondary immune response I occurs upon second exposure to an antigen I faster and stronger than the primary immune response 248 Antibodies are the weapons of the humoral immune response 0 antibodies are secreted by plasma effector B cells into the blood and lymph 0 antibody molecule is Yshaped with 2 antigenbinding sites specific to the antigenic determinants that elicited its secretion 249 Antibodies mark antigens for elimination 0 antibodies promote antigen elimination through several mechanisms 0 mark invaders which triggers mechanisms to neutralize or destroy invaders complementation remove the inactive antigen How can one helper T cell stimulate both humoral and active immunity By releasing stimulatory proteins that activate both cytotoxic T cells and B cells 0 all effector mechanisms have specific recognition and attack phase followed by a nonspecific destruction phase indicating that the humoral immune response works with the innate defenses 2411 Helper T cells stimulate the humoral and cellmediated immune responses 0 cellmediated immune response T cells on surface of or inside of body cells many viruses 0 humoral response ID and help destroy invaders outside of body cells bloodstream interstitial fluid etc o Helper T cells and cytotoxic T cells 0 primarily responsible for cellmediated immune response 0 helper T cells also stimulate humoral response 0 For one helper T cell to stimulate both humoral and active immunity it releases stimulatory proteins that activate both cytotoxic T cells and B cells 0 in cellmediated immune response an antigenpresenting ce displays 0 foreign antigen nonself molecule and one of the body s own self proteins to a helper T cell c Helper T cell s receptors recognize the selfnonself complexes 0 can then activate cytotoxic T cells and B cells 2412 Cytotoxic T cells destroy infected body cells 0 cytotoxic T cells are the only T cells that kill infected cells 0 bind to infected body cells and destroy them 2413 CONNECTION HIV destroys helper T cells compromising the body s defenses 0 AIDS acquired immunodeficiency syndrome 0 results from infection by HIV human immunodeficiency virus 0 bt 1981 and 2007 AIDS killed more than 27 million people 0 most AIDS death occur in nonindustrialized countries 0 In some African nations about 40 of adults are HIV positive 0 The AIDS virus usually attacks helper T cells impairing the o cellmediated immune response and humoral immune response 0 opening the way for opportunistic infection 0 AIDS patients typically die from opportunistic infections and cancers that would normally be resisted by a person with a healthy immune system 2414 CONNECTION rapid evolution of HIV complicates AIDS treatment HIV mutates faster than any pathogen ever studied New strains may be resistant to AIDS drugs Drugresistant strains now infected new patients evolution of AIDS virus is the number one obstacle to eradicating AIDS 22715 Disorders of the Immune System 2416 CONNECTION Malfunction or failure of the immune system causes disease 0 In autoimmune diseases 0 immune system turns against the body s own molecules 0 Examples include I lupus I rheumatoid arthritis I insulindependent diabetes mellitus I multiple sclerosis In immunodeficiency diseases 0 immune components are lacking o recurrent infections are frequent immune system may be weakened by 0 physical stress 0 emotional stress 0 students are more likely to be sick during a week of exams 2417 CONNECTIONS Allergies are overreactions to certain environmental an gens allergies are hypertensive exaggerated responses to antigens allergens in our environment allergic reactions typically occur 0 very rapidly in response to tiny amounts of an allergen allergic reactions can occur in many parts of the body 0 nasalpassages o bronchi 0 skin antihistamines interfere with histamine s action provide temporary relief and often make people drowsy anaphylactic shock o extreme lifethreatening allergic reactions I peanuts shellfish bee venom etc o can be treated with injections of epinephrine