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Ch 43 Notes - Chapter 43 The Immune System Immune...

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Chapter 43 The Immune System 4-3-06 Immune system -internal defense system; protects against certain toxins and disease causing organisms; made of many types of cells and tissues throughout the body; pathogens -disease-causing organisms; include viruses bacteria fungi protozoa immunology -study of internal defense systems of humans and other animals -immune system depends on ability to distinguish self from nonself resulting from macromolecules on surface of cells (or bacteria) ranging from 10-1000. This model is limited though. Better one is danger model danger model -which hypothesizes that the immune system does more than distinguish between self and nonself. It responds to danger signal from injured tissues, such as proteins released when cell membranes are damaged. (THUS, Immune system has abilty to distinguish self from nonself and respond to injured cell chemicals) cell signaling -communication among cells; directly though means of surface molecules and indirectly by releasing messenger molecules -AIDS affects T cells which are an important part of the immune system -allergic reactions are caused by over functioning of immune system NONSPECIFIC AND SPECIFIC IMMUNITY: AN OVERVIEW 1. Distinguish between specific and non specific immune responses 2. compare, in general terms, the immune responses of invertebrates and vertebrates immune response - process of recognizing dangerous or foreign macromolecules and responding to eliminate them. Two main types of responses. nonspecific immune response - or innate immunity ; provide general protection against pathogens, parasites, toxins, cancer cells Includes skin protection, phagocytosis. pathogen-associated molecular patterns are taken advantage of. important aspect includes immunological memory specific immune responses - aka adaptive or acquired immunity ; are highly specific antigen - molecules that the cells of the immune system specifically recognize as foreign; proteins are most powerful antigens. also are polysaccharides and lipids antibodies -highly specific proteins that recognize and bind to specific antigens immunological memory -the capacity to respond more effectively the second time foreign molecules invade the body. Invertebrates launch non specific immune responses -include hard exoskeletons, mucus, phagocytes phagocytes -amoeba-like; engulf and destroy everything
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antimicrobial peptides -developed very early in evolution; more than 800 peptides, which inactivate or kill pathogens, have been described; are very effective due to small size ( a dozen or few amino acids) allowing diffusion and rapid production Toll group - important family of signaling receptors; first found in drosophilia; Toll receptors recognize some common molecular features of classes of pathogens called pathogen associated molecular patterns or PAMPs pathogen associated molecular patterns - or PAMPs; include double stranded RNA of certain viruses and peptidoglycan in Gram-positive bacteria * most invertebrates have primarily nonspecific immune system with limited specific.
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