BIOL 252 1st Edition Lecture 16 Outline of Last Lecture I. LiverII. Adrenal GlandsIII. Lymphatic SystemIV. Lymphatic Vessels and LymphV. Lymphatic tissuesOutline of Current LectureI. Lymphatic OrgansII. Nonspecific DefensesIII. Specific DefensesCurrent LectureI. Lymphatic Organsa. Tonsilsb. Thymusi. Where T cells maturec. Spleeni. Filters blood d. Lymph nodesi. Where lymphocytes gather to come in contact w/ pathogensii. Lymph comes from excess interstitial tissue fluidiii. Filter lymphII. Nonspecific Defensesa. Difference versus specifici. Nonspecific: react the same way regardless of what pathogen is b. Physical Barriersi. Skin1. Keratinized stratified epithelium2. Secretions (acid mantle, dermicidin)ii. Mucous membranes:1. Acid, mucus, lysozyme (breaks down bacteria) iii. Beyond the epithelium1. Hyaluronic acid: viscous component of ECMc. Leukocytes (white blood cells) and macrophagesThese 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. Made in red bone marrowii. Phagocytes1. Macrophages (big cells); phage – engulfs (work in part by engulfing bacteria)2. Neutrophils and eosinophils – engulf pathogens through phagocytosis iii. Basophils, mast cells1. Signal to phagocytes and lymphocytes2. Blood cell = basophil3. Mast cell = connective tissue cell4. Release hormones and attract other cells to site of injury or injectiona. By dilating or hemo-attraction (release chemicals)5. Histamine: vasodilator6. Leukotrienes: attract leukocytes7. Heparin: anticoagulant d. Natural killer cellsi. Non-selective lymphocytes that destroy cancerous or infected cellsii. Releases perforins – pokes holes in cell membraneiii. Releases granzymes that flow through pores and kill cell iv. Cells die by apoptosis v. Present in blood, lymph, lymphatic tissue/organse. Defensive proteinsi. Interferons: newly infected cells send warning message to neighbors; response includes antiviral proteins (AVPs)ii. Limits infection rather than stopping itiii. Complement: 1. Lyse bacteria through formation of pore complexes (part of non-specific)2. “Label” bacteria for destruction by antibodies (part of specific response)3. Enhance inflammatory response 4. Work with antibodies – hence “complement” f. Inflammationi. Signs: swelling, heat, redness, pain, itchinessii. Result of inflammatory responseiii. Inflammatory chemicals cause RBC to move into areag. Feveri. Raise in body’s temperature ii. Hypothalamus in charge and keeps body temperature hovering around 37Ciii. Infection and pyrogen secretion => hypothalamic thermostat is reset to higher set point1. Benefits: chemical reactions go faster 2.iv. Onset – body temperature risesv. Body temperature oscillates around new set pointvi. Infection ends, set point returns to normal => body temp returns III. Specific Defensesa. Includes: T and B cells, antigen presenting cellsb. T cellsi. Cytotoxic (CD8)1. Cell killers ii. Helper (CD4)1. Facilitate Tc cell and B cell activationiii. Regulatory T cells1. Terminate immune responseiv. Memory T cells1. Descend from activated Tc; responsible for memory in cellular immunityc. Can potentially respond to anything d. Make T cells in bone barrowe. Travel to thymus through the bloodi. Learn self tolerance and immunocompetenceii. Self tolerance: do not attack yourself (only virus-infected you)iii. Get rid of one’s that are not self tolerantiv. Immunocompetence: ability to function in the immune system1. Ability to respond to MHC (major histocompatibility complex) on antigen presenting cells v. Somehow a T cell never makes it to the thymus and grows up happily in the spleen. Which is a consequence of this scenario?1. T-cell will be able to bind MHC, but not recognize foreign antigens2. T-cell will be able to bind MHC, and recognize foreign antigens3. Answer: T-cell will be unable to bind MHC, but not recognize foreign antigensa. If we go to thymus, come out with ONLY Immunocompetent cellsb. If it doesn’t go to the thymus, we can’t conclude anythingi. Mixture of both Immunocompetent and