PSIO 202 1st EditionExam #2 Study GuideLymphatic System:Study Questions Lecture 12:Summary of the Immune System Defenses:Innate Defenses Acquired DefensesPhysical barriers B Lymphocytes (Antibody-mediated immunity)– Humoral (body fluid) – (10-15%)PhagocytesFeverInflammation T lymphocytes (80%)-Helper T cellsCytotoxic T cells (cell-mediated immunity)ComplementNatural Killer Cells (5-6%)What do Lymphatic Vessels do? Drain excess ISF and return it to the blood streamWhere do they originate? They originate in “close-ended” lymph capillaries that lie adjacent to the blood capillaries in the tissue spacesAre they larger or smaller than blood capillaries?Slightly largerHow are they similar to blood vessels? They have “one-way” valvesWhere can Lymph nodes be found? Lymph nodes are found at irregular intervals along the lymph vesselsWhat are the Lymphatic system functions? Return excess ISF to circulation; immune responses-protect body from infection; transportation of dietary fatsWhat are lymphatic tissues made out of? Reticular connective tissue-3D meshworkWhat occupies the space within the meshwork?Large numbers of lymphocytes and phagocytesWhat organs contain significant lymphatic tissue?Red bone marrow; thymus; lymph nodes; and the spleenWhich are the primary lymphatic organs? Red bone marrow; thymusWhich are the secondary lymphatic organs? Lymph nodes; spleenWhat do mucosal associated lymphoid tissuestake care of?The GI tract; the Respiratory tract; the Urinary tract; the Reproductive tractWhat do cutaneous associated lymphoid tissues take care of?The skinWhere can lymphocytes be found? They reside in the spleen and lymph nodes where immune responses are often initiatedWhere do B cells reach maturation? In the bone marrowWhere do T cells reach maturation? In the thymusWhat is the first line of defense against invasion by pathogens?Non-specific (innate) immune systemWhat are the innate defenses? 1. Physical barriers2. Fever3. Inflammatory responses4. Antimicrobial substances and cells that can kill and/or orchestrate the killing o pathogensWhat are those antimicrobacterial substances?Phagocytes, complement proteins, interferons,and natural killer (NK) cellsHow does a lysozyme act as a response fighter?It degrades the cell wall of a microbe by making it susceptible to destructionWhat are some of the physical barriers to pathogenic invasion?The skin, mucus membranes, hair, acid, and tearsHow is the skin a physical barrier? It contains sebaceous glands, sudoriferous glands (sweat glands), and lysozymesHow are mucus membranes barriers? Mucus is secreted by specialized epithelial cells called goblet cells that make microbes difficult to infiltrate the body and make foreignwaste easier to digestHow is the hair a barrier? Nose hairs; cilia on special epithelial cells that line the trachea capture material and bring it up to the throat to swallow and digestHow is acid a barrier? The pH of the stomach is about 2.0 and destroys bacteriaHow are tears barriers? They contain lysozymesHow is a fever a defense? An abnormally high body temperature is in response to invading microorganisms. The body’s thermostat is reset in response to pyrogensWhat are pyrogens? Chemicals that are secreted by phagocytes exposed to bacteria and other foreign substancesHow can high fevers be dangerous? They can “denature” enzymes How can moderate fever be beneficial? The liver and spleen sequester iron and zinc (needed by microorganisms); it increases metabolic rate which speeds up tissue repair, and then triggers production of interferons that signal to macrophages to destroy the microbeHow does inflammatory response act as a defense?This is a response triggered whenever body tissues are injured. It prevents the spread of damaging agents to nearby tissues, disposes cell debris and pathogens, and sets the stage for repair processesWhat are the four cardinal signs of acute inflammation?Redness, heat, swelling, and painWhat are the phases of phagocyte mobilization?1. Leukocytosis2. Margination3. Diapedesis4. ChemotaxisWhat is leukocytosis? Neutrophils are released from the bone marrow in response to leukocytosis-including factors released by injured cellsWhat is margination? Neutrophils cling to the walls of capillaries in the injured areaWhat is diapedesis? Neutrophils squeeze through capillary walls and begin phagocytosisWhat is chemotaxis? Inflammatory chemicals attract neutrophils to the injury siteHow do antimicrobial substances enhance the innate defense?Attack microorganisms directly and hinder its ability to reproduceWhat are the most important antimicrobial proteins?Interferons and complement proteinsWhat are interferons? Proteins that are produced by natural killer cells, macrophages, virus-infected body cells, and T-lymphocytesWhat are cytokines? Interferons and other chemical messengers that warn adjacent cells and alter cellular activitiesWhat are complement proteins? They provide a second line of defense against invasion of pathogensWhat does the complement system refer to? At least 11 proteins that complement or enhance the action of antibodiesHow do complement proteins work? Complement proteins attach to antibody-antigen complexes and result in the formation of a “membrane attack complex” (MAC) and then attract phagocytes, stimulate phagocytes,and inflame infected tissuesHow do natural killer cells work? They are specialized T-lymphocytes that kill tumor cells and some viruses via cytolysis – some AIDS patients have a lowered NK cell count in their bloodWhat do NK cells secrete? They secrete a perforin which perforates the cell membrane and makes is susceptible to destructionWhat is the process that NK cells kill microbes?1. Recognition/adhesion2. Rearrangement of Golgi apparatus3. Secretion of perforin, granulysin, andgranzymes4. Lysis of abnormal cells*Study Questions Lecture 13What are the two types of adaptive immunity?Antibody-mediated immunityCell-mediated immunityWhat are antigens? Specific foreign proteins that alter cellular reaction and form an immune responseWhat is immunogenicity? The ability to stimulate proliferation of specificlymphocytes and antibodiesWhat is reactivity? The ability to react with the activated lymphocytes and antibodies released in response to themWhat are the complete antigens? Foreign proteins, nucleic acids, some lipids, large polysaccharidesWhat is cell-mediated immunity specificity? Specific T-cell receptors expressed on the surface of