Chapter 22 Immune System Part II Reading 2(1) PDF

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Chapter 22 Immune System Part II: Major Concepts/Reading #2 Readings: pp. 864- 877, p. 878, pp. 880- 883(Section 22.4- Section 22.7,Section 22.8b, Section 22.9) 1st exposure - takes 3-6 days to make antibodies, 2nd exposure; faster and more effective - 1-2 days ● Distinguish between the three basic characteristics of the adaptive defense system - Responds in strong ways tailored to particular antigens. a. Differs from the innate system in that it’s specific, systemic, and it improves/memory, Third line of defense attacks particular foreign substances (takes longer to react than innate) - Humoral immunity - makes antibodies; - Cell-mediated immunity - recognize and respond to process antigens; Cell mediated immunity refers to how the body deals with microorganisms that have invaded cells (e.g., viruses, certain bacteria and fungi). - Antigen types: complete, incomplete, self - Antigens - Substances that can provoke the adaptive immune system and cause a response. a. Large, complex molecules not normally found in the body. (Nonself/foreign  antigens.) b. Self antigens are molecules produced by the body that stimulate the adaptive immune system. They can result in autoimmune disease. ● Distinguish between complete & incomplete antigens - •Immunogenicity- ability to stimulate proliferation of specific lymphocytes & antibodies - •Reactivity- ability to react with activated lymphocytes & antibodies released by immunogenic reactions o What is a hapten? What does it cause to occur in the body? - formed when small molecules link with body’s own proteins, body recognizes as foreign, results in hypersensitivities ● Explain major histocompatibility complex - cells surface proteins that mark cell as self, creates problems associated with transfusion reactions and tissue rejections - class I - found on virtually all body cells, in infected cells, bind fragments of foreign antigens that come from within the cell except RBCs - inside,  endogenous - class II - displays foreign antigens from outside the cell, exogenous ● Define immunocompetence & self-tolerance - Involves lymphocytes; originates in red bone marrow, Principal cells of adaptive immunity. 2 main types: B’s and and T’s. - Immunocompetence - each lymphocyte must be able to recognize one specific antigen by binding to it - Self- tolerance - each lymphocyte must be unresponsive to self-antigens so it doesn’t attack the body’s own cells - B lymphocytes/cells - humoral immunity - T lymphocytes/cells - cell - mediated immunity - Each lymphocyte has many copies (10^4- 10^6) of a receptor on its cell surface. The presence of one specific type of receptor allows each clone to bind/recognize and interact with 1 specific type of antigen - Once a B or T cell has become immunocompetent, the naïve cells will travel to the lymph nodes, spleen, or other lymphoid organs to await antigens. ● Explain the function of antigen-presenting cells

Antigen presenting  cells = Dendritic cells and macrophages. a. Engulf antigens and present antigen fragments to Helper T cells. b. Identifying the invading antigens and then displaying it to the specific appropriate lymphocyte and saying – “Hey these invaded us. Find them, build an army, & kill ‘em!” ● Describe B cell clonal selection: activation, proliferation, & differentiation Activation - B cell binds with it’s antigen Proliferation - that one B cell makes clones of itself Differentiation - cells become specialized; plasma cells (are antibodies) or memory b cells (are long lived, can last for years) In Secondary response you skip proliferation and make way more plasma cells or antibodies, better equipped *KNOW HOW TO DRAW -

● Distinguish between the primary & secondary immune responses of the humoral immune system - Primary immune response - occurs on 1st exposure to particular antigen - Secondary immune response - occurs if re-exposed to same antigen, faster and more effective a. The initial encounter with a particular antigen is termed the primary immune response. b. It typically has a lag period of 3-6d  btwn the time of exposure to the antigen and the appearance of antibodies specific for that antigen in the plasma.

c. During this lag period clonal selection and antibody production both take place. d. Plasma antibody levels peak at about 10d and then decline. e. In the secondary response, the presence of memory cells primed for the original antigen will result in : i. A shorter lag time. ii. Plasma cells that live and function for a much longer time. iii. Achievement of higher antibody levels in a shorter time. iv. Higher efficiency of binding between antibodies and antigens. ● Distinguish between active & passive humoral immunities and identify examples of each - Active humoral immunity - when B cells encounter antigens and produce antibodies against them - Naturally acquired - bacterial or viral infection - Artificially acquired - vaccinations - Passive humoral immunity - antigens from donor - Immunological memory does not occur, protection ends when they naturally degrade in body - Naturally acquired - fetus, breast milk - Artificially acquired - rhogam, rabies/tetanus/snake bite treatments ● What is another term for antibodies? - Immunoglobins(Ig’s) five types - IgM, IgA, IgD, IgG, and IgE - Part of blood proteins, gamma globulin - Synthesized and released by plasma cells in response to an antigen - Capable of binding specifically with that antigen ● Explain the mechanisms used by antibodies (“PLAN”) - P - precipitation - L - lysis; - A- agglutination - N - neutralization ● ●

Distinguish between Class I & Class II MHC proteins and how they function Class I - displayed by almost all body cells (except RBCs) Recognized by cytotoxic T cells (CD8) Displayed on plasma membrane (endogenous antigen) Class II - only on surfaces of cells that present antigens to CD4 cells dendritic cells, macrophages, B cells Exogenous antigens (antigens from outside cell) Describe T cell clonal selection: activation, proliferation, differentiation

● What is the function of

● helper T cells - help activate B & T cells, induces B &T cell proliferation, helps macrophages to become more potent killers, releases cytokinese to recruit other immune cells, w/o it no adaptive immune response ● ● Cytotoxic T cells ● Regulatory cells -...