BY 124 1st Edition Lecture 18Outline of Last Lecture Chapter 42 I. ElectrocardiogramII. Systems of blood flowIII. Different types of circulatory systemsIV. Differences in fetal circulationV. BloodVI. Blood Compositiona. Plasmab. Cellular elementsi. RBC1. Hemoglobin ii. Plateletsiii. WBCOutline of Current Lecture Chapter 43I. Things that the immune system must doII. Types of immunitya. Innateb. AcquiredIII. Lymphatic systemCurrent LectureChapter 43These 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.I. Things that immune system must doa. MUST recognize selfb. Must recognize non-selfc. Must remember non-selfII. Types of immunity (Figure 43.2)a. Innate – doesn’t care what you are, just knows that it is non-selfi. All animalsii. Rapid responseiii. Broad range of pathogen recognitioniv. Barriers (external):1. Skin2. Mucous membranes a. Mucous membranes – traps stuff so it cannot enter into cell3. Secretionsa. Chemicals in tears and saliva called lysozymes – breaks down thingsb. Sebum c. HCl in stomach kills bacteria in food in stomachv. Internal defenses:1. Phagocytic cells – all WBCsa. Neutrophils – 1st on sceneb. Macrophages – biggest help; “big eater”i. Activated monocyteii. Figure 43.31. Takes in through vacuole → vacuole breaks down → released iii. Figure 43.61. Macrophages look for Toll-like receptors to aid in recognition of things to “eat”2. Mmacrophage will also recognize flagellin – humans do not have flagellin so obviously it will be a prokaryotic cell3. Macrophages recognize lipopolysaccahrides/ helper proteins4. Recognize double stranded RNA 2. Natural killer cells – type of cytotoxic lymphocyte that is importantin innate systema. Important in going after cancer cells & virus-infected cellsb. Sends out blast of granules that causes cells to lyse3. Antimicrobial proteins – complement importanta. Have zymogensb. Pokes holes in cells and causes to lysec. Attracts WBCs to come in and fight battled. Interferons – specific to virusese. ** bridge between acquired and innate responses4. Inflammatory responsea. Figure 43.8b. Basophils and mast cells create histamine c. Direct response of histamine: vasodilation i. Areas get hot and red because there is increased blood flow due to vasodilation ii. Swelling – capillaries get more permeable and fluid leavesd. Prostaglandins – make more blood get into areae. Macrophages come in and act as “clean-up crew” and will clean up everything left over after the “battle”f. Fever – chemicals are released by macrophages and other chemicals are released called pyrogens and both of these will “reset” thymus which increases temperature. Temperature increases because it is another defense against the pathogens because they do not like/cannot function at higher temperaturesb. Acquiredi. Only occurs in vertebratesii. Very specific pathogen recognitioniii. Slower responseiv. Depends on lymphocytesv. Humoral response:1. Antibodies defend against infection in body fluids2. Will respond to a pathogen that is free within the blood/tissue fluid3. B cellsvi. Cell- mediated response:1. Cytotoxic cells defend against infection in body cells2. Very specific 3. “suicide bombers” – kills our cells in order to kill bad cells4. T cellsvii. Lymphocytes (Figure 43.10)1. Starts as Lymphoid stem cells → can specify into T cells (matures in thymus or B cells (matures in bone marrow)2. B cells are found in Bursa of Fabricus3. Found in blood, lymph, and lymphoid tissues4. Antigen receptors (membrane bound)a. Binds to something on protein/bac/venom/poison/foreign substance → responds and becomes activated → producesantibodiesb. Specificc. B cell receptor (Figure 43.9)i. Disulfide bridges holds chains togetherii. Y shaped iii. 2 heavy chains and 2 light chains1. Constant regions and variable regionsa. Variable regions only found on light chains and tells cell what to bind to b. V region will bind to epitope of a protein on pathogen and will then trigger release of receptorsd. T cell receptor (Figure 43.11)i. Alpha and beta chainii. Held together with a disulfide bridgeiii. Do NOT release receptorsiv. T cell will bind to a self-marker and a non-self markerv. Major histocompatibility locus (MHC molecule)1. Two classes:a. Class 1 – important in distinguishing self and non-selfb. Class 2 – found on cells of immune system – how they communicate with each other e. Two types of T cells i. Cytotoxic T cell – kills itself in order to destroy bad cellsii. Helper T cell – calls other cells in to helpIII. Lymphatic system (Figure 43.7)a. Edemab. Swelling is excess of fluid (from fluid that does not return into venous side from arterial side of capillary beds)c. 1 way, not circuitd. Veins (no arteries)e. Valvesf. Skeletal muscles help push stuff throughg. Fluid in lymphatic system = lymphi. Carry into chest → R lymphatic duct or thoracic duct → empty into subclavian duct → into circulatory system through subclavian veinh. Lymphatic organs → have/ produce lymphocytes (WBCs)i. Adenoidsii. Tonsilsiii. Thymus – right above heart; as you age, thymus gets smalleriv. Spleen – sorts RBCsv. Appendix – vestigial organvi. Peyer’s patches – patches in small intestine and lungsLymph