PNB 2275 1st EditionExam # 2 Study Guide Lecture 1 2/17Immune System1. Lymphatic System:- Produces and maintains immune cells- Removes excess fluids from body tissue to maintain body fluid homeostasis- Transports fat and large proteins2. Vessels of the Lymph System:- Lymphatic Capillaries- different than the circulatory system, it is not continuous, it originates as apocket. Has thin walls and a large diameter to maintain a low resistance- The lymphatic capillaries then drain into lymphatic vessels, which are similar to veins but have one-way valves. - They then finally drain into collecting vessels which is the last vessel before it drains into the venous system.- Lymph flow is done by skeletal muscle pumps and peristaltic smooth muscle contration3. Lymphatic Tissue:- Diffuse collection of lymphocytes- No capsules (differentiates it from lymph organs)- They are specialized extensions of skin- Examples are nodules, tonsils, mucosa lymph tissue (MALT)- They are located at sites in which the body secretes or absorbs stuff, which is an avenue for infection hence why they are located at these sites. 4. Lymph Organs: structure is specific to screening fluid for pathogens- They are encapsulated- Macrophages- specialize in phagocytosis- Dendritic cells- antigen presenting cells that commence the immune response- Efferent lymphatic vessels- Examples are lymph nodes, thymus, and spleen- Germinal center- the core of each lymph organ. Contains actively dividing B cells.5. Spleen: specialized lymph organThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Screens lymph fluid- occurs in the white pulp, contains dendritic cells- Red pulp filters blood, stores iron, and has a fixed amount of macrophages*major sites of leukopoeisis (production of leukocytes) are red marrow and thymus *Interleukin-7 drives lymphoid stem cells to become B cells and natural killer cells*B-cells & T-cells are a part of the specific immune system & Natural killer cells are non-specific*Thymus has a blood thymic barrier which prevents T-cells from being exposed to antigens until they are mature. 6. Roles of Immune Responses- Defend against pathogens- Immune surveillance- Eliminates damaged self-cells- Can causes allergies, autoimmune diseases, and transplant rejections7. Examples of Pathogens- Bacteria, Parasites, Fungi- Living cells containing all machinery needed for reproduction- Viruses- Not living and uses the host for reproduction- Toxins- Also not living, peptides or proteins released by living cells that can lead to disease- Pathogens have control points-point of entry, they must bind to the host cell in order to infect it-during the reproduction cycle you can slow the growth of pathogens until the immune system destroys it.-interfere with the release of toxins8. Nonspecific Defenses- General defense that is not targeted against a specific, unique, a specific, unique pathogen or toxin.1. Skin: first line of defense-contains protective chemicals such as lysozyme of saliva, antimicrobial peptides, sticky mucous, cilia, mucous (traps pathogens, transports out of body) 2. Phagocytes: Microphages (neutrophils and eosinophils) & Macrophages (fixed in lymph organs or circulation)-they are capable of recognizing foreign pathogens because they have receptors that recognize the difference between host and pathogen 3. Immunological Surveillance- Monitor normal cells for presence of abnormal markers- Natural killer cells attack any cells that express abnormal markers (produced bylymphoid stem cells in the bone marrow). They are activated by targeting cells that are marked as damaged by Fc-receptors which bind the Fc portion of antibodies. They are also activated by the release of cytokines by infected cells. Activation of NK cells involves kinase signaling. *cooperation between NK (non-specific) and cytolytic T-cells (specific) is important in early phases of infection or if pathogen down regulates MHC I thus preventing T-cell mediated immunity. 4. Interferons: made by host cells which are created to interrupt viral life cycle.-Small proteins produced in response to viral infection-Released to protect neighboring uninfected cells-It is used with chemotherapy to treat many cancers 5. Complement System: complement antibodies- They circulate as inactive zymogens-activated by protease cleavage (two pathways) C3b attachment*activation initiates to the formation of the cell-killing membrane attack complex (MAC)- 1. Classic Pathway (antibody dependent) 2. Alternative Pathway *every cell in the body is protected by surface bound CCP’s (complement control proteins) by blocking C3b 6. Inflammation- Increases flow of plasma and leukocytes into tissue causing symptoms such as edema, redness, and heat.- Triggers phagocytosis of foreign material- Activation of hemostasis and the complement system- Eliminates foreign material ends responseRecognition of microbes and damaged self by the innate immune system (nonspecific)- The innate system recognizes a limited number of structures common to various types of pathogens- Examples are PAMPs and DAMPsPathogen-Associated Molecular Patterns: nucleic acids, unique protein features, complex lipids and carbohydratesDamage-Associated Molecular Pattern: stress proteins (heat shock proteins)9. Toll-Like Receptors: TLR- Found on the plasma membrane (which sample what occurs in extracellular space) and in the endosome (which sample damaged DNA and viral nucleic acid)- TLR 1 &2 = bacterial lipids- plasma membrane- TLR 2 = bacterial peptides- plasma membrane- TLR 3= dsRNA- endosome- TLR 4= LPS- plasma membrane- TLR 5= bacterial flagelin- plasma membrane- TLR 6= lipopeptides- plasma membrane- TLR 7= ssRNA- endosome- TLR 8= ssRNA- endosome- TLR 9= CpG DNA- endsome- TIR signal into cytosol which lead to: 1. Activate NF-kB-mediated inflammation in the cell membrane 2. Drive production of interferons in the endosome*Key inflammatory cytokines: IL-1, IL-6, and TNF (tumor necrosis factor)- inflammation is a factorin increasing phagocytosis, increase adhesion of molecules by endothelial cells, and endogenous pyrogen (they stimulate fever).*neutrophils are the body’s first responders to bacteria. *babies are immunologically naïve*Natural induced immunity is being exposed by environmental means and Induced is purposely being exposed such as a vaccine. Lecture 2