2.Describe the effects of aging on the immune system. oImmune function decreases d/t changes in lymphocyte functionoDecreased T cell activity d/t decrease thymus sizeoDecreased B cell function d/t decrease in antibody production in response to antigenic challenge, increases in circulating immune complexes and in circulating autoantibodies (antibodies against self-antigens)3.Explain the physiologic differences in fetal and neonatal immune function. Stage of Development Immune Function Differences
Fetal Antibody production deficient-Last trimester, fetus capable of producing a primary immune response (IgM only), but is unable to produce a significant IgG response-Active transport facilitates the passage of maternal antibodies into the fetal circulation (d/t size of immunoglobulin, unable to diffuse across cellular layer) NeonateAt birth, total IgG levels in umbilical cord= adult levels, but when cord severed, antibody titers begin to drop (IgG levels, antibody titers)-Causes recurrent mild respiratory tract infections Inflammation 4.Examine the process of inflammation. 2ndline of defense, rapid, nonspecific and short-liveda.Analyze the role and function of the key players in the inflammatory process and describethe implications for clinical practice. Key PlayerRole and Function **Mast Cell*Major step & has effect on every other aspect of inflammatory cascadeoFound in loose connective tissues close to blood vessels- central cell inflammation (most important activators of inflammation) oFound in skin, gastrointestinal, respiratory tractsoDegranulation leads to: activation of acute phase reactants (coagulation proteins, kinin, and complement)oRelease of 4 main items: Histamine, cytokines, leukotrienes, prostaglandinsoCauses of mast cell activation:physical injury (heat, mechanical trauma, ultraviolet light, xrays), chemical agents (toxins, snake/bee venoms, proteolytic enzymes, antimicrobial peptides), immunologic means (anaphylaxtoxins released during activation of complement components or particular types of antibody- IgE- produced by cells of the adaptive response), activation of TLRS (toll-like receptors) by bacteria and viruses -Involved in initiating allergic responsesHistamine 1Pro-inflammatory-Present on smooth muscle- especially bronchi (causes muscle to contract=bronchorestriction)Histamine 2Anti-inflammatory (suppresses leukocyte function)-Found on parietal cells of stomach mucosa and induces secretion of gastric acid as part of normal physiology of the stomachCytokinesSecreted for regulation of innate/adaptive resistance by affecting other cells-Pro-inflammatory or anti-inflammatory-May react quickly (IL 4) or delayed (IL 13)-Diffuse over short distances, bind to appropriate target cells, affect function of the target cell-Some diffuse over long distances (systemic induction- ie: fever)LeukotrienesAcidic, sulfur-containing lipids that produce effects similar to those of histamine -Released when the mast cell degranulates, slower/ more prolong inflammatory response *important for later stages-AKA reaction substances of anaphylaxis (SRS-A)
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